Abstract: The present invention features an electric motor control system combination with at least one electric motor having a field winding and an armature winding connected in series. The system also includes a first power terminal, a second power terminal, a current-limiting resistor, and a current sensor. The current-limiting resistor and the current sensor are connected in series between the first power terminal and the second power terminal. A contactor has a contact operable to shunt the current-limiting resistor. A microcomputerized control connected to the contactor and the current sensor governs the contractor to shunt the current-limiting resistor when the electric motor is not in a plugged condition. The contactor is operative when the current sensor detects a substantially zero current through the electric motor.

Abstract: A system for controlling separately excited shunt-wound dc motors, where control is achieved through microprocessor-based independent PWM control of a chopper (armature) and an H-bridge (field). Connected to the armature is an armature voltage amplifier for varying the applied armature voltage. A field voltage amplifier is also provided for determining the direction of motor rotation and varying the voltage applied to the field winding. A first sensor is connected to the motor armature in order to determine the motor rotational speed. A second sensor is connected to the armature circuit in order to determine the armature current. A third sensor is connected to the field circuit in order to determine the field current. A decoupling controller uses the motor speed and armature current information, and adjusts the armature voltage and the field voltage. An optimal controller uses the motor speed, field current and armature current information, and adjusts the armature voltage and the field voltage.