The latest Simply Smart electronic over-current protection relays from Telemecanique, a brand of Schneider Electric, give greater protection and more machine load control functions used alongside traditional motor starter thermal overload protection. The LT47 and LR97D relays have several features in one product and are designed to work in conjunction with motor starters. The inexpensive control and protection relays have a definite time operating characteristic.
This new relay range particularly benefits machines with a high risk of difficult starting, machines with high inertia or torque that changes over time, and machines with a high probability of jamming.
The LR97D is the only over-current protection relay designed to fit beneath the base of the Telemecanique TeSys model D motor starter, while the LT47 mounts separately but can be used with third party products. Both are simple to use but have more features, such as LED signalling for easy diagnostics, than would be expected for the price. Both can be used in single and three phased motors, and they are available with manual and/or automatic reset facility and cover a range of sizes up to 60A. Control voltages are from 24 to 230V.
The LT47 and the LR97D relays take into account rapid variations in load, and have two independent timers, providing protection both during starting (“D” time), and during the steady state (“O” time). The relays are
certificated to UL, CSA and CCC.