MOTOR OVERLOAD COIL CONTROLLER AND CONTROLLER AND CONTROL METHOD FOR MONITORING MOTOR TEMPERATURE

PROBLEM TO BE SOLVED: To obtain a motor overload coil controller, a controller and a control method for monitoring the motor temperature at a relatively low cost. SOLUTION: A motor load coil controller 10 being used in a motor starter/ contactor comprises a plurality of inputs/outputs, a motor overload circuit, i.e., an input/output reducing circuit 14, and a microcontroller 12. The plurality of inputs/outputs includereset inputs 36, 38, a current sense input 20, an FLA input 30, coil control inputs 42, 44, 46, a coil control output, a state output 62, and the like. The controller 10 comprises an FLA regulator 28 and a current sensor for monitoring the motor temperature. The microcontroller determines an analytic time interval for determining the motor temperature, receives a current sense signal during the analytic time interval periodically and executes a multi-step calculation subroutine.