The Model 455
3-phase voltage monitor combines load and line side monitoring to alert the user of contactor failure or impending contactor failure.  The line side monitoring will protect the motor from damaging line side conditions prior to the motor starting. With other line-load side voltage monitors, the motor must be started before a voltage problem is detected. With the Model 455, the motor is fully protected at all times.  The motor will not start when a power problem is present.  The Model 455 is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50*/60Hz motors regardless of size.  The product provides a user selectable nominal  voltage setpoint and the voltage monitor automatically selects between the 200V and 400V range. Other adjustments include a 2-30 second trip delay, a 2-300 second restart delay (and manual restart) and a voltage unbalance trip point adjustment from 2-8%.  Four LEDs indicate the status of the Model 455: run light, undervoltage, overvoltage and phasing fault. The Model 455 is a load and line side monitor that does not require a separate power source for its electronics, making it much easier to install.