Used in conjunction with a two-pole voltage tester, Megger’s new MPU690 proving unit provides a fast and dependable method of confirming that circuits are dead prior to carrying out work on them. The new proving unit features time-saving automatic operation and its high output power makes it suitable for use with lamp type voltage testers as well as with more modern units.
To ensure safety, when a two-pole voltage tester is used to confirm that a circuit is dead, the correct operation of the tester itself must be verified using a known live voltage source both before and after checking the circuit. Often, however, no suitable voltage source is available. The new MPU690 provides a convenient and reliable alternative.
Compact, robust and easily accommodated in any toolbox, this battery-operated unit generates a range of test voltages from 50 V to 690 V in five steps, and has a 50 Hz output that accurately mimics the normal mains supply. For added convenience, the MPU690 has a magnetic back that can be used to secure it to steel enclosures and similar surfaces, and it has terminals that are widely spaced to allow use with shrouded probes.
The operation of the MPU690 is fully automatic. As soon as the probes of the voltage indicator being checked are connected to the unit, it turns on and initially produces an output of 690 V. After a short delay, it then slowly ramps down through each of the other voltage steps before switching itself off. The voltage steps are indicated by individual LEDs and an additional LED is provided to confirm that the batteries in the proving unit are healthy.
The batteries used are readily available standard AA types, and the design of the unit is such that these have a very long service life – typically around 550 tests. The MPU690 measures just 130 x 68 x 48 mm and weighs less than 350 g including batteries.
Megger
www.megger.com
