Heater Controller

Whether retrofitting an existing starter or installing a new one, Motortronics MWH Series is easy to apply. Just wire it in parallel to the magnetic starter’s line and load connection, connect the necessary auxiliary contacts and installation is complete. Output voltage is factory set to maintaina +5° to 10°C differential above ambient temperature. This adjustment can be used to trim the control as required for each application. In addition to built-in fuse protection, the MWH Series features an RC snubber circuit across the SCR which protects it from any rapid rate of change in the system voltage. A metal oxide varistor (MOV) protects the unit against voltage spikes for reliable, maintenance-free operation. Designed for fully automatic operation, the MWH Series turns on when the motor starter has turned off. A built-in one minute timer ensures that the motor magnetic field has collapsed before it injects DC power into the windings. When the motor is restarted, the MWH Series instantly turns off. No operator interface is required, the MWH Series is in control. The MWH Series had an optional shutdown input that can be connected to the N.O. auxiliary contact on the motor starter’s thermal overload relay. This will disable the motor winding heater control, preventing any additional heating in the motor and allowing for a faster motor cool down period. The MWH Series then goes back on-line after the overload relay is reset.