Abstract: A DC trailing cable system for tethered machines is disclosed. The DC trailing cable system may include a power center configured to provide DC power having a controlled voltage value. In addition, the DC trailing cable system may include a tethered machine comprising one or more inverters and one or more motors, wherein the one or more inverters are supplied DC power, at least in part, from the power center via a two-core trailing cable, and wherein the one or more inverters are connected to the one or more motors.

Abstract: A reversible DC motor drive includes a DC/DC converter having a DC input, a first output having a first pulsed DC voltage and first DC voltage value, a second output having a second pulsed DC voltage and second DC voltage value, and a third output having a third pulsed DC voltage and third DC voltage value. The first and second outputs are adapted for electrical interconnection with armature terminals of a DC motor, and the third output is adapted for electrical interconnection with a field terminal of the motor. A microprocessor routine calculates motor speed from the motor armature voltage, field current and armature current. An outer control loop for motor speed and two separately controllable inner control loops for armature and field current control the DC/DC converter responsive to the calculated motor speed and a speed reference in order to independently control the three DC voltage values.

Abstract: A compact, low loss, transformer-less, reversible dual motor controller for electric vehicles, capable of regenerative braking, and providing good cornering capabilities is described, comprising an AC/DC or DC/DC converter and reversing power switching means to allow either forward or reverse motion. The controller can be modified to allow electric vehicle operation under slippery bottom conditions by the addition of switching means to connect the two DC motors in series across the output of the converter when motoring, and temporarily in “circulating-current-free armature parallel” mode, when one motor spins as a result of slippery bottom conditions.

Abstract: A reversible DC motor drive includes a DC/DC converter having a DC input, a first output having a first pulsed DC voltage and first DC voltage value, a second output having a second pulsed DC voltage and second DC voltage value, and a third output having a third pulsed DC voltage and third DC voltage value. The first and second outputs are adapted for electrical interconnection with armature terminals of a DC motor, and the third output is adapted for electrical interconnection with a field terminal of the motor. A microprocessor routine calculates motor speed from the motor armature voltage, field current and armature current. An outer control loop for motor speed and two separately controllable inner control loops for armature and field current control the DC/DC converter responsive to the calculated motor speed and a speed reference in order to independently control the three DC voltage values.

Abstract: A contactorless multi-motor controller is described which comprises a contactorless pump motor starter and a contactorless, reversible traction motor controller. The two controllers are mutually interactive. When the pump motor has ramped up to full voltage, a function block on-board said pump motor control circuit detects this condition and enables the tramming operation of the traction motor.

Abstract: A method of controlling and a controller for controlling at least one series motor is provided. Rectifier means is connected in series with the motor so that current through a field winding of the motor is always in the same direction irrespective of the polarity of the input voltage while the current direction through an armature of the motor reverses in accordance with the polarity of the input voltage. An energizing current is applied to the field winding by a bias power supply to ensure that the field winding always produces some flux during operation of the motor.

Abstract: An electric powered vehicle or the like includes a first mechanical drive system for a first side of the vehicle and a second mechanical drive system for a second side of the vehicle. A first DC motor and a second DC motor are respectively coupled to the first mechanical drive system and the second mechanical drive system. A source of DC power is on the vehicle. The first DC motor has a first field and a first armature and the second DC motor has a second field and a second armature. The first field, the first armature, the second field, and the second armature are connected in a series circuit with the source of power. A voltage sensing relay across the first armature can detect a high voltage across the first armature to sense a loss of traction of the first mechanical drive system. A switching circuit is employed to disable the first motor from the series circuit in response to the voltage sensing relay.