Features

Jim Wallace of Seaward looks at developments in PAT data management software systems

With a competitive portable appliance testing market forcing all contractors and PAT contractors to work more efficiently, linking the test functions of tester to effective results programs has taken on increased importance.

Fortunately, advances in portable appliance testing instrumentation and test data management software means that there are now integrated PAT solutions available that meet the needs of all levels of electrical safety testing.

In very basic terms PAT testers could be regarded simply as test data collection tools that measure and check the safety of electrical appliances. For fully effective risk management programmes and compliance with workplace safety protocols, how this data is acquired, managed and presented takes on even greater importance.

As a result, considerable work has also gone into the development of PAT record keeping software systems to enable the user to build and maintain computerised records of test results so that the collected data can be interrogated and used to control electrical safety programmes in a professional and orderly manner.

In addition, the HSE Memorandum of Guidance on the Electricity At Work Regulations 1989 advises records of maintenance and safety test results should be kept throughout the life of the equipment.

Software controlled safety testing record systems enable ‘real-time’ records to be maintained, which are easily amended and updated. This enables new equipment to be added and the movement of equipment from one location to another to be tracked.
Programs used for asset management purposes in this way can search through records very easily and display the record details significantly faster than making changes to a manual paper based system – and with reduced chances of mistakes being made.

Another advantage is the ease with which re-test schedules can be planned. As the re-test periods for individual items could be anything from three months to four years, it is comparatively easy for test situations and work schedules to become unmanageable. It becomes particularly unwieldy to have someone monitoring a paper record system looking for items which may have remained in use beyond their next test date, particularly when large workplaces or testing contracts can include thousands of appliances.

Now, matching the availability of different testers, a range of results recording programs possess different features and varying levels of sophistication to meet the needs of all types of PAT testing organisations and personnel.

Manual data entry systems
In their most basic form, PAT record keeping programs provide database packages capable of storing and presenting large numbers of test records.

Because most entry-level PAT testers provide simple pass/fail readings and do not have an internal memory for results storage, complementary software programs at this level permit manual entry of results.

With these systems, once test results have been entered there can be a range of data manipulation options available that allow different test report templates to be produced – for example, as PDF, TIF or jpeg files.

In addition some of these elementary or basic level programs also allow different reporting options including the presentation of test histories for individual appliances for comparison or trend analysis purposes.

More elaborate entry level packages also have the ability to link testing carried out to the automatic generation of invoices – including the option to include the costs of any repairs carried out.

Once testing has been undertaken and all data entered, it is also possible to produce special ‘certificates of testing’ that can be displayed in workplaces to highlight the electrical safety measured undertaken.

Direct data download
For those PAT testers equipped with a memory to record results, basic software packages are also available that enable the direct download of test results into database systems.
Of course one of the most important considerations for users of PAT testers incorporating an internal memory is the compatibility between the test instrument and the PC program. Most software packages are compatible with different safety tester output formats – although as the range of test instruments has increased over the years it is worth checking with the supplier of your preferred results recording program that your tester will be compatible.
Some of these types of programs allow both manual and direct download input of data and in broad terms provide the same range of test report options and administrative functions as those described earlier.

However there are some differences that may be attractive to different types of PAT contractor or user: For example some programs enable test results to be downloaded into existing customer or site specific files – while some download programs produce multiple databases with new results listings being created every time a new set of results is entered.

Uploading test data
As PAT testers have become more sophisticated, some have the ability to ‘pre-program’ the instrument with a special testcode (a test routine defined by a numeric sequence) at the start of the working day.

This is referred to as an upload capability and involves the ability to send an appliance number and testcode from PAT records held on a PC program to the instrument. By uploading this information into the tester, re-testing in the field can be speeded up considerably and detailed test histories can be maintained very easily.

As a result software programs that combine data upload and download features can be used to create fairly sophisticated asset registers for customers, grouping appliances by type or location and helping to track the movement of equipment between departments or different parts of a building.

Such high level programs also come with a host of other functions and test templates – including the inclusion of ‘view only’ CD files that enable others to have copies of test records from a parent program that can be viewed without having a copy of the original record-keeping program software.

Other features include sophisticated presentation and reporting options and the ability to link electrical safety testing records with other asset management or maintenance functions - extending the use of these programs for more general facilities management tasks.

For contractors carrying out PAT testing as part of more general facilities management functions, software programs are available that include the ability to include reports and details of other health and safety related checks on equipment such as emergency lighting, fire alarms and fire extinguishers.

Networking options have also been developed for these higher level PAT programs - enabling more than one user to access the program at the same time.

Special programs
In addition to the range of record keeping database programs a number of special software packages are available to provide specific test management or PAT administrative functions.
One example is an e-scheduler module that systematically interrogates the PAT test database and automatically identifies when equipment will be overdue for re-test – issuing e-mail alerts to notify customers or departments immediately of all re-test requirements or overdue warnings.

In this way this special software can be used to highlight and plan re-test schedules, enabling workloads to be managed efficiently. For testers with an upload capability this program can also directly transfer the appropriate test data into test instruments in preparation for on-site testing.

The system can also be configured to submit formal re-test price quotations with the alerts for a complete test scheduling and costing proposal, boosting repeat business and enhancing the levels of customer support provided.

Another example of ancillary is special time manager software that provides information on the test activity of individual users and engineers – providing such details as time of test, number of tests undertaken and time between jobs.

Analysis of such information enables service or contract managers to understand how often testers are being used, identify improvements in staff training and help field staff to test faster and work more efficiently.

With developments such as these, PAT results recording and data management solutions are available for all organisations involved in portable appliance testing whatever their requirements.

At all levels PAT record keeping programs provide real practical benefits to contractors – reducing costs, increasing revenue and productivity, improving safety and providing a truly professional approach to test data management that can only help in the long term development of their business.


Footnote: To help employers learn more about portable appliance testing Seaward has published a free booklet -
‘A Common Sense Approach to Electrical Safety in the Workplace’. This describes the importance of implementing inspection and testing measures that are appropriate to the particular working environment and which are in keeping with the specific risks posed. Further details call 0191 586 3511 or visit www.seaward.co.uk

Escalating energy costs coupled with a drive to reduce carbon footprints have resulted in a number of changes in the UPS industry. An initial development was the introduction of modular, scalable UPS solutions which enabled higher system efficiency through ‘rightsized’ power protection. However, recent product introductions boast up to 99% efficiency. While such numbers may be eye catching to potential purchasers, ‘high efficiency’ options can increase potential risk to the critical load. Shri Karve, director of business development, APC by Schneider Electric provides a guide to plus points and pitfalls when specifying UPS for data centres and critical loads

There has been a general assumption all UPS designs and technologies are born equal. It’s not difficult therefore to see why there has been a certain tendency to conclude all UPS topologies afford similar levels of protection. Essentially there are two generic types of UPS available at present - Static and Rotary covering various topologies (VFI,VI & VFD)- although it is important to understand that Static UPS enjoy the lion’s share of a global market forecast to grow in 2010 to $7.3b (IMS Research, Uninterruptible Power Supply Sourcebook, July  2010).

Static units range from 200 VA to 1600 KVA as single modules which can be connected in parallel to achieve larger outputs and or redundancy of N+1 or N+N. Rotary UPS are mainly available from 500 KVA to 1600 KVA as single modules and suitable for paralleling to reach larger ratings. There are a number of key areas to consider when selecting which type of UPS system will provide optimum protection at a competitive price. Criteria include criticality, UPS type, configuration/ availability, load rating/ battery autonomy, maintainability & installation/ structural considerations.

Criticality
The very first question is one of mission criticality, in other words what are the consequences for an organisation if a mains disruption or outage crashes its computer system or renders IT services unavailable. Depending on the application consequences may extend from a temporary inconvenience to the paralysis of the entire business. Apart from just continuity of power, quality of power is also very important for IT equipment.

Appropriate UPS selection should therefore provide protection from grid related disturbances including blackouts, brownouts (sags), dynamic overvoltage, overvoltage, undervoltage, transients (surges), frequency variations, voltage distortion Hf (burst) and harmonics. In addition, power disturbances generated within data centres, caused by lifts, HVAC, inrush current from printers or even a loose neutral connection must also be mitigated.

UPS types and codes
Industry standards have been developed to describe the technical characteristics and therefore protection afforded by various UPS topologies. IEC  62040-3 provides very clear definitions for each UPS type complete with typical block diagrams :

1. VFI –  the UPS output is independent “of Input mains supply Voltage and Frequency variations”, i.e., the primary power path is the inverter and not the AC mains for true double conversion on-line topology.

2. VI  -  the UPS output is dependent “on Input supply frequency variations, but Mains supply Voltage variations are conditioned (independent)...”.

3. VFD  -  the UPS output is dependent  “ on Mains Input Voltage and Frequency variations”.

Ensuring the correct balance between efficiency and resilience.
Double conversion (VFI) UPS systems protect the load continuously (with no switching risks) against voltage/frequency variations from the utility. However, in the recent past a number of UPS manufacturers are trying to reach unrealistic high (99%!) efficiency by sacrificing electrical power quality demanded by Servers and adding risk of unwanted source switching right at crucial moment of UPS operation. In other words such UPS systems are expected to switch between various modes of operation –VFD, VI and VFI. This kind of operational switching can impact on system resilience (due to prolonged switching periods) and reduce MTBF resulting in very low Availability values due to increased MTTR.

In addition to availability implication, high efficiency UPS also sacrifice power quality demanded by IT equipment. It’s essential never to expose the IT load to raw mains by running the UPS in bypass mode. Even if the bypass path has a harmonic conditioner and choke, it does not provide clean, conditioned and isolated power required by IT equipment. A series choke within the UPS bypass path will limit fault clearing capacity, increase losses due to load harmonics and make discrimination more difficult.

A typical diesel rotary UPS is not double conversion and does not correct frequency swings during normal operation. Furthermore, Rotary units have a very high component count resulting in very low MTBF. When utilised for IT loads, the units need a 150% oversized neutral to handle a high level of Triple ‘n’ harmonics. Blade servers impose a leading power factor load on UPS and therefore this must be a key factor during selection of larger UPS systems. However, UPS systems can be highly underutilised making it necessary for input harmonic filters to hold the distortion level (THDI) at 5% right across the load range. There is a trend to utilise a PFC type active charger resulting in very low (4%) input harmonics and almost unity input power factor.

From a scalability point of view, static units are easily retrofitted within a building, but the same cannot be said for rotary UPS, mainly due to structural issues and noise problems. Further complications may have to be addressed due to vibrations, fuel storage, fire risk, wet stacking (caused due to light load running) and exhaust fumes.

Load rating / battery bank
Sizing of UPS needs to account for Crest Factor and harmonics from the PCs and servers, not ignoring blade servers which have leading power factor and very high inrush currents. Generally all UPS units are rated for specific KVA of load at 0.8 lagging power factor. Battery autonomy must be adequate to protect the load during blackout and batteries need to be monitored as they are the weakest link in any power protection system. For larger systems it is worth sizing the battery for end of life and to meet ENBS6290 Pt.4 1997. Multiple battery strings are advisable for critical applications.

It’s common practise to have up to 15 minutes autonomy backed by diesel generators capable of handling leading power factor loads presented by blade servers. Sites without secondary generators may need a minimum of 30 minutes’ autonomy plus software to ensure a graceful IT shutdown and to protect against data corruption or loss.

Configuration / availability
In order to achieve high levels of availability, built-in system redundancy (N+1 or greater) and fast service from manufacturers are recommended. It may be worth using static transfer switches near the PDU since this improves both availability, maintainability and limits fault propagation.

Installation / maintainability
These disciplines are subject to an article in their own right as the siting and installation of equipment is a complex subject. Static UPS does not require air-conditioning but battery room needs to be maintained at temperature range - 10 to 25 C for extended life. From a maintenance point of view, this should be carried out on a regular basis either by the manufacturer’s own team to protect product liability insurance cover, or at the very least by factory-trained personnel if using a third party for this function.  Maintainability and spare parts provision are important as these have a profound effect on availability.

Conclusions
When selecting UPS systems for critical applications, the specifier must consider the impact of a loss of IT services on the organisation, since this will almost certainly cause financial loss or damage to brand. Newer, high efficiency static UPS may achieve 99 % efficiency, but only momentarily and with all the associated risks to the IT load posed by VFD operation. Rotary UPS pose a number of problems, limited scalability, the noise they create and their long maintenance period requirements.

Double conversion (VFI) UPS systems are up to 97% efficient and will protect an IT load continuously (with no switching risks) against mains events and outages. A small trade-off, perhaps, but compensated by a great deal of peace of mind where IT continuity and resilience is vital.

Our grumpy old man is seeing red. But it’s not Santa’s suit in his sights, but the fact our power distribution is now under Chinese control that’s got him hot under the collar

It’s Christmas and we’ve gifted our power to the Chinese. I have prattled on (and on) in this column about the concerns I have about the security of Britain’s electricity supply. Now I am starting to spit feathers with the news that Cheung Kong Infrastructure (CKI) and Hongkong Electric has bought Eléctricité de France's (EDF) UK electricity distribution networks for £5.78bn.

As a kid, most of my plastic Christmas toys came from Hong Kong. Now it’s our power that comes courtesy of that province.

That we should be dependent for one of our most vital resources on the policy, ethos and ethics of completely remote overseas business more than sits uncomfortably with me… it bloody terrifies me!

We all know how creaking our power distribution infrastructure is – yesterday I had another hour long outage (in spite of being 10 minutes from Dungeness B and the windfarm at Little Cheyne Court) – and I very much doubt CKI and Hong Kong Electric will be too enamoured about the costs of infrastructure renewal in our congested metropolises.

When will GB Limited and our illustrious new coalition leaders grasp that we must absolutely be masters of our own destiny against the backdrop of rapidly increasing demand and diminishing affordable power supplies? I am in despair.

Anyway, enough of that before I require defibrillation.

It being that time of year, I couldn’t resist looking at the Electrical Contractors Association’s guidance on the safe use of Christmas lights. While what the ECA has published makes absolute sense and I would not argue with a word of it, I had an amusing recollection from many years ago when I was still an engineer.

In the run in to Christmas, a variety of my company’s offices strung assorted lights and other paraphernalia around their otherwise gloomy lairs. A directive was circulated that all such adornments were to be taken down until they could be re-erected by qualified electricians. Now, I suspect at the time (late 70s) it had more to do with union demarcation than safety, but who knows? What I recall was the merriment it caused and the pressure it put on the firm’s electrical services team. To most of us it seemed like of foretaste of the nanny state that was to come over the subsequent three decades.

I have seen some terrifying lash-ups perpetrated by the great British public (and many other publics come to that matter). Cables connected using Sellotape, single 13A plugs with six separate sets of lights wired into them (and on a 13A fuse to boot), open connections exposed to wind and rain… the list goes on. If nothing else, such practices do endorse the need for RCDs!

My point is the ECA’s worthy warning will not reach those who need to hear it. Electrical contractors are not stupid and to give advice that lights might short or that plug connections may have become loosened is rather like instructing one’s parents’ parents to do the proverbial to some eggs.

Finally, can I send a Christmas wish to Santa? I’ve been a good boy… grumpy, but good, honest.

I would like:
A sensible energy policy based not on rhetoric or political posturing but based on need, best and most appropriate available technology and firm resolve.
A solid programme of regeneration, affordable housing and infrastructure investment that will keep electrical engineers and contractors gainfully employed for years to come without boom and bust cycles.
A shiny new generator set might be useful because I think it’s only a matter of time before I will need one.

Finally, may I wish you all a merry Christmas and the kind of new year that leaves us all a little less grumpy!
 

John Houston can be contacted on 01797 364366
or by e-mail at This email address is being protected from spambots. You need JavaScript enabled to view it.

As the UK economy continues to stutter out of recession, many in the electrical and electronics sector are working hard to take advantage of the slowly improving climate. While it is important to grasp business opportunity while it is there, getting involved in helping a charity can be extremely rewarding and worthwhile.  Pat Sheldrake, head of fund raising operations for the Electrical and Electronics Benevolent Association (EEIBA), looks at how volunteering to support those who’ve given so much to our industry in the past can be extremely satisfying, as well as reaping rewards for the beneficiaries

With the difficult economic climate continuing to bite, everyone is feeling the squeeze on their finances. Individuals and companies are all pulling in their belts and with the recently announced cuts in public sector spending, this is in turn having an effect on all charities with EEIBA being no exception. However, there are many ways to support and help our industry’s own charity, even if it is not possible to dig deep individually from a donation point of view.
The work of EEIBA takes many forms as each year the charity gives support and advice and if necessary, financial help to a wide range of beneficiaries who work or have worked in the electrical or electronics industry. Beneficiaries come from all walks of life and can include electricians, van drivers and those who have worked in manufacturing or even high street electrical retailers. Additionally, relatives and dependents of those from the industry can also be eligible for assistance in certain circumstances.

The advisory help provided can include subjects such as debt counselling, something which continues to cause problems for many, particularly in light of increased redundancies in the UK since the recession. Similarly, financial help also encompasses all kinds of scenarios, such as those in need of specialist equipment for their homes, or a wheelchair to enable them to get around better, through to providing vital respite breaks for those who may be caring for their relatives.

There are many ways to become involved and help to ensure the valuable work of EEIBA is able to continue. One of the main ways the charity is funded is via events such as our annual powerBall which is a popular, key calendar date for the industry and takes place in London every November. This year an incredible £220,000 was raised from the night. For those unable to make the journey to London, most EEIBA regional branches run their own Christmas parties and summer balls which are a great way to contribute while being able to enjoy a highly social evening.

In addition to social gatherings, there’s other activity based events such as golf days, horse racing days and angling competitions. These regional days also provide a highly enjoyable way of boosting the charity’s funds while at the same time networking and socialising with colleagues and friends from our industry.

As an organisation, EEIBA relies heavily on the support and hard work of our branches and as well as attending events, getting involved with your local region can really give a boost to finances. Even helping with organising events can make a massive difference to the amount of money that can be raised.

These days more and more people are undertaking activity challenges such as running marathons or half-marathons, as well as cycling, hill walking and even swimming the English Channel, to name but a few. It is a great way of training for a specific challenge and getting fit, while helping others and the sense of elation and achievement upon completion can never be underestimated. Frequently it is the bigger, more widely known charities that benefit from these efforts and while money raised for any charity is fantastic, those who work in our industry might like to consider taking part to fund raise for EEIBA next time. For example, there are dedicated EEIBA spaces available for next year’s London Marathon so if you want to run, why not think a bit closer to home and do it for your own industry’s charity?

EEIBA has just launched a new fund raising pack to assist those wishing to get involved in helping to boost the charity’s finances.

For those who haven’t quite decided how they’re going to fund raise, the pack includes ideas such as organising sponsored bike rides and golf days and the less energetic can also get involved with charity karaoke nights and cake sales.

The packs have been designed to support and inspire our army of seasoned fundraisers as well as those who’ve never been involved with EEIBA before.

Despite the commercial pressures we all face in our day to day lives, giving up a small amount of time to attend an event or fund raise will make a real difference to EEIBA, its work and most importantly, the beneficiaries.

For more information on EEIBA, to make a donation or to get involved in fundraising, contact 020 8673 9821 or visit www.eeiba.org

Automation within the plant environment goes beyond installing technologies such as variable speed drives and programmable automation controllers. The need for greater integration of process operations means organisations also need to deploy an integrated communications hierarchy - one which can be expanded over time as the business develops and can be adapted to meet changing needs. Here, Jez Palmer from Schneider Electric discusses the process

Over the past few years, businesses have faced an increasing amount of pressure to introduce integrated processes within their plant environment. However, the implementation of standard technologies, work processes and best practices still need to be maintained wherever possible. Therefore, the need to operate in an open environment is the modern approach that has been adopted by organisations as they address the structure of their communications hierarchy.

Barriers to information still exist between energy management and process automation systems interacting with operations management and enterprise systems. Those in the process industry should consider the impact that these barriers to information have on productivity, business opportunities, lifecycle costs, and the realisation of a strategy for operational excellence in today's plants. Process suppliers need to move to a single environment where the energy management and automation systems seamlessly interact with operations management applications.

Organisations face a number of challenges, primarily as they attempt to implement an open communications hierarchy. A shift of this nature will then enable them to subsequently move away from the proprietary standards and technologies that have previously been the legacy of yesterday’s energy management and process automation systems.

As an organisation changes and evolves, its operations will do the same in order to cope with the increased amounts of productivity. Businesses must improve in speed and agility to respond to the demands of customers, the drive towards energy efficiency, as well as regulatory pressures and standards. In addition, companies need to change in line with their competitor markets, sustainability initiatives and the views and needs of the shareholders. To manage such demanding levels of change, channels of communication must exchange information that facilitates automation and communication within the workplace.

Improved integrated systems can offer businesses a solution to successfully address operational efficiency at the right level within a plant environment. Creating a fully integrated organisational management system can often be perceived as a complex task, but in theory it should actually be achieved at a relatively basic level by having systems that operate through a standard communications hierarchy. By combining data from each of the operating systems within a common infrastructure, the business will have better control and visibility, a clearer understanding of its energy usage and productivity as well as easier and improved maintenance – a considerable number of benefits.

The breakdown of barriers between process automation, operations and energy management has been raised as a common issue for some time, although organisations are working hard to look to help address the problem. An obvious solution would be to manage operations from one single environment, which means production applications such as plant asset management, performance management and scheduling can seamlessly integrate into the same communications infrastructure as the energy management and control systems functions.

There are clearly a number of benefits to having a communications hierarchy in place. What will be pleasing to hear is that this is easily achievable and there will not be too much upheaval for businesses while the system is being introduced. Many organisations have aging systems that are still in use, but nearing the end of their useful life. When the time comes to improve these outdated technologies, businesses should consider utilising new devices that feature communications technology already imbedded in them.

To put this into context, look at the benefits of Schneider Electric’s SoCollaborative integrated software suite, to include engineering tools, as well as HMI, SCADA and historian functionality. SoCollaborative incorporates networking and communications that are built on Ethernet, which facilitates the open and transparent communication between the field, process, plant and enterprise. Network technologies and web services ensure that there will an efficient sharing and distribution of information between sensors, instrumentation, devices, controllers, operator workstations and other third party systems. The process organisation also benefits from open fieldbus and device network connectivity.

A big advantage for businesses is that implementing such a solution brings consistency throughout all process control disciplines, including engineering, operating and monitoring, maintenance and data storage, as well as reporting and optimising. It provides much needed assurances to businesses that its solutions are integrated while supporting collaboration, which helps to drive energy management at all levels of a process organisation. What is also helpful for businesses is that they can measure and analyse data, delivering advanced trending and processes visualisation as part of its standard operating and monitoring modes.

Introducing a common communications hierarchy also allows businesses to own their plant and processes, prolonging asset life through the collection and storage of all process, quality and energy data from across plant sites. From this, detailed reports can be generated to help in the decision making process by leveraging historian and process optimisation functionalities.

It is, however, important for businesses to recognise in order to meet with internal change and demand; organisations must implement a clear and concise communications hierarchy to provide an open and collaborative environment where operations embrace standards. Also, where necessary, the business needs to adapt and utilise the full scope of the automation and communications hierarchy.

Taking these steps will enable a business to successfully evolve into the future, as operations can then intelligently adapt to incorporate energy management and control systems into their business information systems.

In today’s plant environment, organisations will be constantly challenged with issues which will incorporate sustainability, preserving capital assets and extending their life, increasing asset utilisation, maximising operational effectiveness, reducing fixed costs, minimising variable costs, and empowering their workers to make it all happen.

Manufacturers are continuously introducing new software solutions into the marketplace, to help businesses reap the long term benefits of managing operations through one integrated solution. Utilising a carefully integrated solution allows an organisation to customise their strategy of energy management benefits, while addressing both automation and energy management requirements, to give a tailored plan which is centred on the needs of the business.

For organisations to evolve, solutions providers such as Schneider Electric look to introduce offerings such as the SoCollaborative software and Planstruxure solutions into the marketplace. This transformation within industry will focus on simplifying processes, to act as one solutions provider, accelerating the drive to address end user needs for customised solutions with strong energy management benefits, thereby capturing a bigger part of the value chain and leveraging its integrated portfolio of businesses by promoting a common architecture and adapting its organisation to align with end user segmentation.

For organisations this results in collaborative solutions that address both automation and energy management needs, then tailoring those solutions to be industry, application, and manufacturer specific to optimise the return on investment (ROI) and return on assets (ROA) for each individual customer.

Schneider Electric has introduced PlantStruxure to address those challenges that are found in organisations on a global scale. Addressing process challenges should involve reducing engineering time, providing high availability architectures, and solving process safety challenges.

High availability is required by all customers whose processes cannot afford an unexpected downtime because the product material costs and/or process start-up costs are high, with aggressive production targets, product quality affected by downtime, and unscheduled downtime, which combined could potentially cause harm to people and/or equipment.

Unexpected downtime may result in lost production and revenue, wasted energy, increased use of raw materials and consumables, higher maintenance costs, and have a possible negative impact to the safety of personnel and equipment. Solutions software, such as PlantStruxure offers tested and proven high availability systems at every process level, focused on providing continuous operations, accelerating the process end user return on investment and increasing plant maintainability and efficiency.

With plastics extruders and injection moulding companies looking to reduce energy usage, minimise maintenance costs and boost productivity, the role of the direct drive torque motor is coming to the fore. Andy Parker-Bates, of Parker SSD Drives Division, explains how the technology differs from conventional motors, and explores the benefits it can bring

They’re known by many names – torque motors, direct drive motors, frameless motors – and often they are thought of as a new technology that needs to be more proven before it becomes a mainstay of industrial automation. So just what are torque motors?

First off, it’s worth making the point this is not an unproven technology. It is a new take on existing brushless servomotor technology that has been around for decades, and is amongst the most reliable technologies available. In short, a torque motor is a rotary brushless servomotor optimised for low speed operation, typically in the order of 50-500rpm. It is a direct drive solution, so there is no need for mechanical transmission elements such as gearboxes.

There are two different kinds of torque motors. There is the more traditional looking motor with frame, cooling system, terminal box and feedback sensor, and then there is a frameless motor made up of two independent elements (rotor and stator) intended to be tightly integrated into the mechanics of the application.

Typical applications for the frameless version include semiconductor manufacture and machine tools, while the framed version meets the needs of applications such as paper machines, crushers, extruders and injection moulding machines. It’s certainly not a panacea for all applications, and indeed below about 30kW it’s questionable whether there are any gains to be had over a conventional motor/gearbox combination at all. But above this, in specific applications such as plastics extruders and injection moulding machines, at a time when end users are looking to reduce operating costs, through better energy utilisation and lower maintenance requirements, torque motors can offer significant advantages.

For starters, a direct drive solution is inherently more energy efficient than a motor/gearbox combination. Modern motors can of course offer high efficiencies and gearbox design has also developed significantly leading to more efficient products. But gearbox efficiency is dependent on the load, the reduction ratio, and the number of stages. Optimum gearbox efficiency is obtained at maximum load, but efficiency decreases dramatically at light loads – down to as little as 20% in worst-case situations. And even in its most efficient load ratings a gearbox will still lose around 2% efficiency per gearing stage.

Further, the motor and gearbox need to be closely matched in order to maximise energy efficiency, and even a good motor/gearbox combination may be only 80% efficient. Additionally, traditional motor/gearbox solutions will also often require belts and pulleys as part of the drive train, further reducing efficiency.

Torque motors, by contrast, improve in efficiency at lighter loads. Thus the direct drive torque motor can easily be between 5% and 12% more efficient than a motor/gearbox combination. If we assume a typical 7% improvement, with an energy cost of €0.10 per kWh, then in 7200 hours operation per year on a 100kW extruder, €5040 will be saved in energy costs alone by switching to torque motors.

Replacing a hydraulic motor to drive the screw on an injection moulding machine, the torque motor could easily offer energy savings in excess of 20%, and deliver higher productivity and clean operation, without the need for fluid changes or the risk of fluid leakage.

We can look at maintenance costs, too. In a typical 110kW DC motor with a gearbox, maintenance can represent a cost of more than €3000 per year. How do we come to that figure? A typical year’s maintenance on a 110kW extruder, maintenance on the DC motor could account for €300 in motor revision, €150 in carbon control/change and €150 in filter maintenance. Gearbox maintenance could contribute €50 in oil draining and €250 in seals replacement, with the potential of €2500 or more in gearbox repairs. And that’s before we’ve considered the cost of downtime in terms of lost productivity.

Use of a torque motor slashes these costs, firstly because it is an inherently low maintenance technology and also because there are no additional drive train components to wear.

Also, without the need for all of these ancillary components, torque motor systems are much quicker and easier to install: having to install and align multiple motors, gearboxes, belts and pulleys on something like a plastics extruder is a process that can take days. By contrast, installing the corresponding number of torque motors can be achieved in just a few hours.
A typical plastics extrusion machine could be using multiple motors, so the savings from not having additional power transmission components quickly add up to something very significant. In a co-extrusion machine, for example, there could be up to nine motors installed in a single machine.

Torque motors also help to address specific machine requirements on co-extruders in the way that conventional motors are unable to match. For example, the screw extraction mechanism may be required from the front of the motor in some instances, but from the back of the mechanism in others. This is readily achievable with some torque motors. At the same time, torque motors with hollow motor shafts can provide extruder screw cooling through the motor, – especially important for big screws.

Torque motors are a low noise, low vibration option. The European Noise Directive 2003/10/CE sets the maximum recommended noise level exposure limits for operators in order to protect against health and safety risks, and sets a maximum noise exposure limit of 87dBA. Above 80dBA, special protective measures must be taken. In a conventional motor/gearbox set-up, just the gearbox alone can often be producing above 90dBA. The torque motor, in contrast, is an inherently quiet technology, producing below 80dBA in most cases, and therefore can play a key role in minimising overall equipment noise levels. Similarly, it is a very low vibration technology. This again contributes to reduced noise levels, but it also has reduced physical impact on the rest of the machinery – ensuring greater reliability – as well as helping to ensure a more uniform product quality.

We also have to look at the costs of downtime in the event of a power transmission failure. Plastics extruders represent some of the most demanding motor applications. Once production has started, the one thing you don’t want to be doing is halting production. The extruder is typically located at the beginning of the production line, so stopping it will call a halt to all production. Because it has to be heated, there are long ramp up times before production can begin. And when there are defects in the output, products cannot simply be recycled and disposal costs are high.

Reliability is therefore paramount. With fewer components in the power train, the direct drive solution is inherently more reliable than a typical motor/gearbox combination, and certainly much easier to replace in the event of a fault, allowing production to be restarted much more quickly.

From the machine builder’s point of view, the torque motor solution is generally much more compact than the motor/gearbox combination. The motor can also offer built-in advantages for specialist extruder manufacturers. An integrated thrust bearing can be added to support back pressure from the screw. This is a nice added feature on injection moulding machines, but is a mandatory feature on plastics extruders. Also, a screw extraction mechanism can be readily built in, making it easy to remove the screw from the extruder for routine maintenance or to allow a new production batch to be set up. And, as discussed, the screw can be cooled by water through the motor, which can be an extremely useful feature on large extruders.

Typical torque motors cover torque ranges from 1200Nm to 22,100Nm, and speeds from 50 to 500rpm depending on size. Water cooling is standard on many designs, but natural ventilation is possible with suitable derating.

With all these advantages, torque motors are steadily making inroads into the plastics extrusion and injection moulding markets. The upfront cost may be slightly higher, but the energy savings, elimination of ancillary components, reduced maintenance costs and improved productivity – not to mention the reduced noise levels – quickly allow users to recoup the premium on the purchase cost. In addition, the more compact design can lead to smaller machines, which frees up valuable floor space, potentially driving opportunities for even higher productivity.

Peter Jones, engineering manager for grid systems at ABB in the UK, explains why HVDC Light connections are set to play a key role in the development of offshore windfarms and outlines ABB’s enhanced 4th generation HVDC Light technology that offers a number of important advantages

Plans are taking shape in Europe for the construction of several very large offshore windfarms – with a total capacity of some 25 to 33 GW - many of which will be in hostile, remote locations in waters around the UK. The design, construction and operation of large-scale power plant 100 km or more out to sea requires significant design and construction skills, especially in creating efficient and reliable links to bring the power to the mainland grids.

The need is for a very robust electrical transmission system with high availability and minimal maintenance requirements that meets not only the strict national grid codes but can also withstand the harsh and sometimes very hostile offshore climate of the North Sea.

HVDC technology
For well over a century, high voltage alternating current (HVAC) was seen as the natural choice for electrical power transmission. However, the capacitance per unit length makes AC cables impractical for transmitting large amounts of power over distances greater than 50–70 km: a significant amount of reactive power is generated, and low-frequency resonances may result in instability.

While classic high voltage direct current (HVDC) technology has been commercially available since the mid 1950s, it has mainly been used for point-to-point, high-capacity bulk power transmission links over long distances or for the interconnection of asynchronous grids. Its active components are high power thyristors. A typical application is China’s 800 kV Xiangjiaba-Shanghai link, which provides the capacity to transmit 6,400 MW over a distance in excess of 2,000 km.

Over the past 13 years ABB has pioneered a new generation of HVDC based on VSC (voltage source converter) technology – HVDC Light – that uses series-connected power transistors rather than thyristor valves. It is ideal for integrating dispersed, renewable generation, especially wind power, into existing AC grids. It is also used for smart transmission and smart grids due to its great flexibility and adaptability.

The world’s first HVDC link to connect an offshore wind farm with an AC grid is the BorWin1 project. Based on HVDC Light technology, this 200 km link connects the Bard Offshore 1 wind farm located off Germany’s North Sea coast to the HVAC grid on the German mainland. This link transmits 400 MW at a DC voltage of ±150 kV and was ready for service in late 2009.

When complete, BARD Offshore 1 will consist of 80 wind generators, each with a capacity of 5 MW. These will feed their power into a 36 kV AC cable system. This voltage will then be transformed to 155 kV AC before reaching the HVDC Light converter station, located on a dedicated platform. Here the AC is converted to ±150 kV DC and fed into two 125 km sea cables, which then continue into two 75 km land cables, transmitting 400 MW power to the land-based converter station at Diele in Germany.

HVDC Light technology
HVDC Light uses IGBTs (insulated-gate bipolar transistors) connected in series to reach the desired voltage level. This technology is used for power transmission, reactive power compensation and for harmonics and flicker compensation.

HVDC Light uses PWM (Pulse Width Modulation) that enables the magnitude and phase of the AC voltage to be freely and rapidly controlled within the system design limits. This allows independent and fast control of both the active and the reactive power, while imposing low harmonic levels (even in weak grids). Normally, each station controls its reactive power contribution independently of the other station. Active power can be controlled continuously and, if needed, almost instantly switched from ‘full power export’ to ‘full power import.’ The active power flow through the HVDC Light system is balanced by one station controlling the DC voltage, while the other adjusts the transmitted power. No telecommunications are needed for power balance control.

From a system point of view, an HVDC Light converter acts as a zero-inertia motor or generator, controlling both active and reactive power. Furthermore, it does not contribute to the grid’s short-circuit power as the AC current is  controlled by the converter.

Offshore wind integration
An HVDC Light converter station’s ability to enforce an AC voltage at any arbitrary value of phase or amplitude is of great value in starting an offshore network. Initially, the offshore converter operates as a generator in frequency-control mode, creating an AC output voltage of the required amplitude and frequency. The voltage is ramped up smoothly to prevent transient over-voltages and inrush currents. Finally, the wind turbine generators are automatically connected to the offshore network as they detect the presence of the correct AC voltage for a given duration. This functionality cannot be realised with classical thyristor-based HVDC transmission, as the latter would require a strong line voltage to commutate against.

An HVDC Light connection can similarly be used for network restoration after a blackout. As a blackout occurs, the converter will automatically disconnect itself from the grid and continue to operate in ’house-load’ mode. This is possible because the converter transformer is equipped with a special auxiliary power winding for the supply of the converter station.


HVDC Light cables
In offshore windfarm applications, HVDC Light uses extruded polymer cables, which are a strong, flexible and cost-effective alternative for severe conditions and deep waters. This cable type has a copper or aluminium conductor surrounded by a polymeric insulating material, which is very strong and robust. The water sealing of the cable has a seamless layer of extruded lead and finally two layers of armouring steel wire in counter helix to provide the mechanical properties.

To see how these cables compare with conventional AC cables, consider the requirements for a 550 MW subsea connection over a distance of 75 km. For an AC scheme, three single-core 220 kV cross-linked polyethylene (XLPE) cables would be required with a copper conductor cross-section of 1600 mm2 and copper wire tensile armour. The weight of the three cables is 3x60 kg/m = 180 kg/m. However, a VSC-based HVDC link would require only two 150 kV cables with a copper conductor cross-section of 1400 mm2 and steel wire tensile armour. The weight of the two cables is 2x32 kg/m = 64 kg/m, that is around one third of the AC scheme. This weight saving reduces both the cable cost and installation cost, while the shorter total cable length (for 2 HVDC cables compared with 3 AC cables) also reduces factory production time scales.

13-year track record
The first commercial HVDC Light scheme was commissioned in Sweden in 1997. Since then 13 projects have been put into operation, with 25 converter stations and a total capacity of over 5,000 MW and more than 2,600 km of cable installed. Over this time the technology has demonstrated an availability of greater than 98%.

HVDC Light has been used for the world's longest land cable, the Murraylink (220 MW, 180 km) in Australia as well as the 105 km subsea Estlink between Finland and Estonia. It is currently being used for Eirgrid’s 500 MW East-West interconnector that will link the Irish and UK grids in 2012.

Evolving technology
The first generations of HVDC Light technology were based on a two-level PWM converter which has been continuously improved. This provides the base component in the CTL (Cascaded Two Level) converter technology now being deployed as part of our enhanced 4th generation (G4) HVDC Light Technology.

The main advantage of the enhanced HVDC Light G4 technology  is the low converter losses of around 1% (compared with 3% for the first generation) due to the low switching frequency provided by the CTL topology. The low harmonic generation also eliminates the need for AC filters and contributes to a very compact installation footprint.

HVDC Light G4 also offers additional flexibility since the maximum rating available within one module is +320 kV and 1150 MW and it is capable of being used with both cables and/or overhead lines.

Summary
HVDC Light is a technology developed over more than 13 years of operating experience for interconnections between AC grids. It offers a number of important features that can contribute to the successful development of wind power as an integral part of the generation mix. Among these are long low-loss submarine cable transmission links, the ability to cope with rapidly variable generation and black start capability.

When it comes to cable management, debates over the suitability of one solution over another are commonplace, but when it comes to the pros and cons of perforated cable tray in relation to wire mesh things can become heated. In order to get a balanced view on the subject Electrical Review spoke to Nigel Leaver, a marketing manager in Legrand’s cable management division, which manufactures and sells both products

Tracking the perforated tray versus wire mesh debate back to its origin is relatively straight forward, with it all beginning when wire mesh first squared up to perforated tray with a view to grabbing market share and establishing itself as the solution of choice.
Ever since, this battle between the new kid on the block and the traditional old master has demanded industry attention, with the two trading blows, but neither being able to deliver the telling, knock-out punch. 

As a manufacturer of both types of tray we are ideally placed to referee such a bout – providing as we do a balanced and non-biased opinion on both solutions. Unfortunately, this neutral position doesn’t mean we can resolve the debate as perforated and wire mesh tray are both perfectly acceptable solutions and both are covered by the same European standard for tray and ladder (IEC 61537).

Instead, the decision of when to use one rather than the other is very much dependent on the installation – meaning the question to ask is not, which is the best, but rather, how do I choose between them?

Round 1
One of the main benefits of wire mesh tray is that it’s said to be cheaper and quicker to install, and in many situations this is the case.

Take for example an installation in a confined space with numerous twists, turns and obstacles to cope with. In this situation wire mesh tray is cheaper and quicker to install due to the fact it is designed specifically to be configured on site without the need for factory manufactured fittings. However, this task does need to be undertaken by experienced installers so as to avoid potential problems such as sharp edges caused by poorly cut and installed fittings.

Of course, installations do vary and if we were faced with one that required numerous straight lengths then we would typically advise in favour of perforated tray. The reason being it’s generally stronger and so only needs supports every 2.0 to 2.5 metres, rather than the 1.0 to 1.5 metre intervals that wire mesh requires. Therefore, with fewer cantilever arms or trapeze hangers to fit, the installation time, and subsequently cost, is significantly reduced.

Round 2
Another differentiating factor between the two that is often picked up on is that wire mesh tray is generally installed using accessories that are made on-site, whereas perforated uses dedicated factory fittings.

Again, the debate focuses on ease of installation, and again no definitive answer can be given. As perforated tray comes with factory fittings, some may say the job of installation is far easier than it is when having to create fittings for wire mesh on-site.

On the other side of the argument, the flexibility provided by being able to create fittings on site can be invaluable – especially when you consider just how quickly these bends and fittings can now be made, and the speed with which they can be secured using clips like our Fastlok. And of course, some manufacturers do now supply factory made bends, tees and risers for wire mesh tray with the aim of tipping the balance in its favour.

Round 3
The suitability of the two types of tray in relation to different cables also needs to be considered. Both can carry power and data cabling, however, when installing power cables these need to be fitted with steel wire armour or a second sheath of PVC-U as perforated and wire mesh tray provide cable support, rather than full mechanical protection.

Following directly on from this, is the question of how cables are secured. In the majority of instances this can be achieved through the use of cable ties, but this approach becomes unsuitable when larger cables, such as 3-phase power cables, need to be carried. Then there is no choice but to secure the cables with specially manufactured cleats, which need to be fixed securely to an already rigid system.

Until very recently this was something that could only be achieved to a satisfactory level using perforated tray, but a UK cleat manufacturer has recently developed, tested and launched a wire mesh clip that provides a strong and reliable means of securing cables with high fault levels, which can be used in conjunction with heavy duty trefoil cleats – a development that allows wire mesh to compete with the traditionally stronger perforated tray on this kind of installation.  

Round 4
Finally, the availability of different finishes should also be taken into account. Wire mesh is most commonly supplied with an electro-plated finish, which is similar to the standard pre-galvanised finish of perforated tray. Both systems can also be supplied in stainless steel or hot dipped galvanised finishes for more aggressive environments. In fact, it’s only when a system is installed in an area where corrosion will be very high, that a difference between the types of finish becomes significant. In these scenarios, perforated tray can be given a thicker galvanised coating (deep galvanised) that uses special sheet steels that can provide a galvanised thickness of at least three times that normally used – a solution that gives an extended product life three times that of a standard hot dipped galvanised product and up to six times that of electro-plated wire mesh cable tray. All of which means, the more aggressive the installation environment, the more suitable perforated tray is.
 
Round 5
In terms of general usage, the rule of thumb tends to be that wire mesh tray is used in applications where the installation is in a false ceiling or cavity floor. One reason for this is that its design allows for better air circulation, thus reducing numerous potential problems caused by overheating cables. Meanwhile, in installations, which are accessible to the general public, and therefore at risk of vandalism or accidental damage, perforated tray provides greater physical protection to the cables due to the fact it’s secured with screws, which are harder to vandalise and less likely to be accidentally dislodged than the quick-fit tabs used to secure lengths of wire mesh tray.

The big fight verdict
As you can see, not only is it hard to say which of the two solutions is better, it is also difficult to provide a definitive guide as to when to opt for one over the other – and, with the strides being made in the development of wire mesh this boundary is likely to become ever more blurred. Therefore, in order to ensure that you get the best possible solution for any given installation, make sure you talk to a company that isn’t biased.

The increase in traffic on existing tracks combined with new high-speed rail projects means rail traction is fast becoming an important load on electric supply grids. This in turn is focusing attention on voltage stability as well as the power quality of the surrounding grids. Rolf Grünbaum, Per Halvarsson, and Björn Thorvaldsson of ABB explain how FACTS (Flexible AC transmission systems) can enhance power quality in rail feeder systems
Part one of this article appeared in electrical review October 2010 or can be viewed at www.electricalreview.co.uk

Load balancing
The traction load, with a power rating of up to 120MW, is connected between two phases. Without compensation, this load would give a negative phase sequence voltage of about 2%. To counteract this imbalance, the load balancer, an asymmetrically controlled SVC, was installed.

A load connected between two phases of a three-phase system can be made to appear symmetrical and have unity power factor – as seen from the three-phase feeding system – by applying reactive elements between the phases.

The HS1 load balancer is optimised to handle a load connected between the ‘a’ and ‘c’ phases. In accordance with load-balancing theory, to balance a purely active load, a reactor needs to be connected between the ‘a’ and ‘b’ phases and a capacitor between the ‘b’ and ‘c’ phases. The traction load has a reactive part which also needs to be balanced. Not only is the asymmetry compensated for, but the addition of a capacitor between the ‘c’ and ‘a’ phases also regulates the power factor to unity.

The load balancer is controlled to compensate for the negative phase sequence component present in the current drawn from the supergrid. Furthermore, the power factor is regulated to unity. The positive phase sequence voltage can also be controlled if the capacity is available. This depends, however, on the load balancer working point.

Capacitive compensation technology for HS1
In the latest project for HS1, ABB is implementing capacitive compensation solutions to prevent voltage drops along the 25kV catenary supply.

There are some areas of the line where the catenary voltage can drop as low as 17.5kV, causing a reduction in overall system performance. These voltage drops result from the inherent design of the isolation transformers (used to isolate between HS1’s AC traction power supply and the adjacent Network Rail DC traction power supply), located in the existing substations along the line, as they require large magnetising currents and therefore demand substantial inductive reactive power. This causes a drop in the voltage supply as seen by the train’s catenary.

A number of studies commissioned by HS1 have demonstrated a reduction in the reactive power demand from the isolation transformers will improve system performance. This will be achieved by the installation of  capacitive compensation equipment that will effectively cancel out the inductive power demand of the transformer, and hence reduce the voltage drop. ABB will design, manufacture, install and commission capacitive compensation filters in nine AC/DC compounds at strategic positions along the line.

SVC Light
With the advent of controllable semiconductor devices capable of high power handling, voltage source converters (VSCs) with ratings beyond 100MVA are now feasible. VSC and insulated gate bipolar transistor (IGBT) technologies have been brought together to create a highly dynamic and robust system with a high bandwidth known as SVC Light, for a variety of power conditioning tasks in grids and beyond. Using pulse width modulation (PWM), an AC voltage almost sinusoidal in shape can be produced without the need for harmonic filtering.

Balancing rail traction loads
With its ability to generate voltages of any amplitude and phase angle, SVC Light can fulfill the role of a load balancer. By connecting the VSC to the grid, SVC Light can be treated as a synchronous machine in which the amplitude, phase and frequency of the voltage can be independently controlled. In addition, with high frequency PWM switching, the VSC is also capable of synthesizing a negative sequence voltage.

Compared to the classical SVC based on delta-connected TCRs for the same rated power, an SVC Light with phase-wise connected valves and a common DC link can compensate a train load that is √3 (1,732) times larger. The delta-type connection is less efficient for balancing unsymmetrical active power than it is for symmetrical reactive power compensation. This difference does not exist if a phase-wise connection is used.

Two SVC Light installations are in operation in the French railway system. Both are fed from the national power grid, one at 90 kV and the other at 63kV sub-transmission levels. At both sites, SVC Light is used to dynamically balance the asymmetry between phases caused by the mode of traction feeding. In these cases, the thyristor locomotives are fed power from two phases of a three-phase grid. The locomotives generate harmonics which are then actively filtered by SVC Light.

SVC Light cost benefits
SVC Light offers not only a technically but also an economically advantageous solution. If SVC Light was not available, then to meet the requirements of imbalance, the supply network in-feed would have to be transferred from 63kV to 225kV or 400kV. This in turn would require the erection of new overhead lines as well as the upgrading of a number of substations currently supplied with 63 kV or 90 kV.

Marco Cable Management’s technical team outlines their most frequently asked installation questions…..

Marco, the UK’s largest manufacturer of Steel Wire Cable Tray, and uPVC Cable Management Company, is committed to supporting customer’s needs, enhancing the installation process through product development and customer support.

This year has seen the launch of a number of new products including the Elite Trunking range, a number of accessories and an anti-microbial protection for uPVC Trunking. To help users make the most of these latest innovations, Marco’s technical team has provided information related to some of the most commonly asked questions:

 Do you have an alternative accessory to the traditional nut and bolt fastening for Steel Wire Cable Tray? What can you do to help reduce installation time on site?

The Marco Strut Clip offers a fast fix alternative to traditional fixings. The strut clip secures the tray in place with just one turn of a screwdriver, making installation quick and simple.
Marco Quick Locks remove the need for nut and bolt assembly kits for producing bends on site, instead simply allowing any fixing to be produced by the means of just one simple clip.

What uPVC Trunking products would best suit specification for both refurbishment and new build hospital schemes?

Marco now offers an antimicrobial protection for all of its uPVC product ranges, including the new ELITE Hygieia Range. These Trunking systems are used nationwide in environments where the spread of infection must be controlled, such as hospitals, care homes, schools and laboratories.

Marco utilises silver ion technology to create a defence against 99.9% of harmful bacteria growth. This provides built in protection from, and prevents the growth of, bacteria, fungi, mildew and moulds, including MRSA, E-Coli, Salmonella, Klebsiella Pneumoniae and Streptococci.
The design of the product is not only aesthetically pleasing, but also prevents dust from settling on flat surfaces.  All fittings have been manufactured without any deep grooves or ridges to eliminate the build up of debris in hard to clean areas.

How do I ensure ROHS compliancy through the specification of products?

Marco’s products are all lead free in their make up and therefore meet ROHS compliancy, giving customers peace of mind when specifying Marco products.

Marco is committed to operating a sustainable business and has recently achieved ISO14001 accreditation, which demonstrates company wide commitment to the environment through various schemes to reduce waste, reuse material and recycle where possible.

All production is UK based reducing the ‘product miles’ and carbon footprint – the company estimate that Marco trays travel almost 400 miles less than the trays of most of its competitors.

Steve Davis of Marco Cable Management commented: “We want to be able to communicate with our customers at every level and support them in achieving their requirements through the specification and installation process. This year we have launched a podcast, re-designed the website and launched a new comprehensive brochure to showcase the Marco range and capability, giving our customers choice in terms of the information platform that suits them best.”

www.marcocableman.co.uk 

Although a standby generator’s usual state is ‘idle’, it must nevertheless start immediately on demand in the event of a mains failure. To guarantee this, it is essential to run a suitable maintenance regime that covers not only scheduled testing, inspection and repair but also emergency call out and spares holding support appropriate to the installation. Uninterruptible Power Supplies Limited’s Kevin Ashton explains how to provide this maintenance cover effectively

The first part of this article can be found in Electrical Review September 2010 or at www.electricalreview.co.uk

A standby generator typically spends nearly all of its life in preparation to supply power in the event of a power cut. The site’s uninterruptible power supply (UPS) system can handle short term mains failures or power outages. A failure that exceeds the UPS battery autonomy will not offer support to the critical load. Therefore when it is unexpectedly called upon, the generator must respond as it’s designed to, delivering the time critical power protection when needed, thus ensuring power continuity.

Generators, like all engines, will suffer from natural wear and tear and can potentially fail. So this failure is identified when the generator is most needed, i.e. during a power failure, it is vital the generator set is covered by a maintenance plan that closely matches the needs of the generator and its applications. This maintenance plan should not only cover maintenance visits, but should include appropriate call out cover and ensure that good spares are available.

Fundamental to any maintenance regime is to ensure  the generator’s engine coolant heaters, or jacket heaters, are keeping the engine block warm and the mains trickle charger is charging the starter battery. The generator is started and stopped from a signal from the Automated Mains Failure (AMF) panel. This should also be checked in a maintenance regime to ensure it is working correctly. The generator on receipt of this signal will typically take 2-10 seconds to provide the power to supply the critical load. The UPS system should, using its batteries, support the load during this interim period.

The cooling system has active elements including a fan, water pump and thermostats as well as a radiator/heat exchanger, hoses and connections that should be checked for leaks. The fan drive pulley and belts should be checked for wear. The fuel system has fuel lines, connections and filters requiring checking, as well as the air and exhaust system components. The lubrication oil system, the starting system and the generator mechanics all have components needing checking for wear, and fluids that must be replenished or changed. Additionally, a load test, typically of two to four hours duration on full load, is recommended.

Onsite visits, though indispensible, cost time and money, so the maintenance plan should meet the clients needs without being excessive and more costly than necessary. During these visits, technicians can perform mechanical and electrical inspection and testing, replacing worn parts, replenishing and changing fluids as required. They can also spot critical component degradation and advise accordingly to arrange for a replacement or repair of the affected part. If required and permissible, the maintenance technicians can test the power protection system’s reaction to a simulated mains failure.

These scheduled maintenance activities are often combined in a maintenance contract with emergency call-out cover, where service levels and response times are set to match the client’s needs and the site’s criticality. Remote 24/7 generator monitoring and testing is another complementary and highly efficient maintenance plan component. Alarms, faults and valuable operational status information are relayed to the maintenance provider’s service centre. An appropriate response is then initiated, with improved ‘first-fix’ rates during site visits. This remote monitoring can have scheduled as well as emergency features. The generator can be automatically started at a pre-set time every week, and run off-load for 10 minutes while checking vital operating parameters including voltage, frequency, battery charge condition, oil pressure, water temperature, emergency stop button and fuel level.
With the UK power station population ageing, extended blackouts appear to be increasingly likely. A generator can effectively offer the required extra protection, above the UPS battery autonomy, ensuring increased power protection for your critical loads.

Our grumpy old man has been sampling the delicacies of duck feet, jellyfish and braised donkey on a Far Eastern sojourn, but his appetite for telling it how it is remains unabated

I have learned a lot in the past few weeks about the probable futility of our attempts to command the tides of global warming. Rather as King Cnut never actually tried to stop the incoming sea, but rather wanted to prove to his people that he couldn’t act as a god, the West’s environmental efforts may yet simply show we are powerless to achieve a clean Earth – at least in our lifetime.

I have just returned from China where I witnessed capitalism going mad. While still essentially a socialist state, with a reasonably strong Communist party, the country has embraced western consumerism in the most ostentatious ways. In Beijing, where traffic gridlocks lasting up to five hours are commonplace, new vehicles are coming onto the roads at a rate of 58,000 a month! Even in Cheng Du, a city of 10.5 million, making it medium sized by Chinese standards, there are 1000 new cars sold every single day.

Visit Shang Hai for the World Expo that’s taking place there and apart from seeing a bustling and vibrant state of the art city, you’ll also be blinded the glorious spectacle of a gazillion lights burning brightly through the night. And it’s all powered from coal. Shang Hai Electric Power Company (the largest of the city’s providers) posted profits in 2009 of RMB 382 million in spite of massive hikes in coal prices.

Against this backdrop, there remain huge tracts of land in the Far East that are still to be properly electrified. This is coupled with a crumbling infrastructure that, outside of the major cities, is unlikely to bear the increasing loads required. This means continuing investment in equipment, but it also means much more generating capacity is needed. Capacity that will almost certainly principally come from coal fired generation.

Paradoxically, China appears, at least superficially, to be very environmentally conscious. The plentiful waste bins deposited around the cities have recycling repositories. In some cities, only electrically powered scooters and mopeds are permitted. Many cities ban heavy goods vehicles from their centres. In Cheng Du, the city will shortly open not one, but seven underground electric rail networks – all at the same time!

China also, of course, retains its strictly governed one child per family policy, so it cannot be blamed for allowing uncontrolled population growth. No, its biggest environmental problem now comes from the expansion of consumerism that we have propounded for so long in the West.

I wonder how much China’s efforts, much like our own, will stem expanding greenhouse gas emissions.

I am a sceptic not a cynic, but one has to retain some objectivity to put into perspective the rhetoric of our politicians and green campaigners. I do believe in conservation. I do believe in reducing all forms of pollution. I do believe we face impending energy crises. But, I do not for one second believe our environmental salvation can come from current green energy technology and reducing consumption. Especially while demand from the world at large continues to grow exponetially.

What I am optimistic about is, with the right emphasis, resources and impetus, humans have the capacity to solve their problems technologically. After all, in homo sapiens’s short history on the planet, we may have screwed some things up, but we’ve solved an awful lot of others. In that, perhaps China’s emerging industrialisation may yet hold a key.