Abstract: A chopper motor-controller for regulating a lift truck traction motor incorporates means for detecting faults which may cause the truck to run out of control, such as the high speed bypass contacts which shunt the semiconductor power switch being welded closed, and for disabling the controller in response thereto and also has time delay means for preventing a directional contactor from closing in on a fault before the fault detecting means can operate to disable the controller. The disclosed controller may alternatively be connected to require the operator to relax the accelerator foot pedal when starting or changing direction or to permit change of direction while the foot pedal is depressed.

Abstract: A motor is electrically coupled to a power source through a motor starter. The motor is selectively operated by a relay to connect and disconnect the power source to the motor. A counter accumulates a count of motor failures and produces an inhibit signal should the frequency of occurrence of such motor failures exceed a given level. The relay is operated by an inhibit signal to cause the motor starter to disconnect the power source from the motor.

Abstract: A motor is electrically coupled to a power source through a motor starter. The motor starter is selectively operated by a relay to connect and disconnect the power source to the motor. A counter is set whenever a select motor temperature condition exceeds a predetermined level to provide an indication of the number of motor starts. The relay is operated to cause the motor starter to disconnect the power source from the motor whenever the motor fails to run continuously during a given time period following a predetermined number of starts.

Abstract: Complete protection of a three-phase submersible pump motor, such as the type used downhole in an oil well, is obtained with a solid state digital logic control system that monitors each of the three phase currents and shuts the pump motor down if any of those phase currents indicates either an underload or overload condition. Time delays are introduced before shutdown to avoid undesired nuisance shutdowns otherwise caused by transient or momentary conditions. When the pump motor is de-energized in response to an underload condition, it is automatically restarted after a predetermined time delay. All of the delay functions are precisely determined by division of the power line frequency. Downhole pressure and temperature are also sensed and if they become excessive the motor is automatically de-energized to prevent overheating. The presence of an auxiliary physical condition, such as filling up a retaining tank, also causes the pump motor to be turned off.

Abstract: A textile card crush roll operating system is driven by a two-speed electric motor completely independent of the main card cylinder driving motor and is provided with starting control means for operating the crush roll motor at slow speed for a pre-determined time according to automatically operable timing means during which interval sliver from the crush rolls is manually fed into an associated coiler and arranged in such a way that tension of the sliver is applied to stop control means which stops operation of the two-speed crush roll motor after the motor is accelerated to its high speed condition under the control of operating control means. Thus if sliver tension is substantially reduced, the crush roll system is automatically shut down.

Abstract: In a friction-fusion apparatus a solid state control circuit including a triac connected in series with an electric motor, and a control circuit connected across said triac including a resistor and a capacitor and a diac connected between the junctions thereof and the gate electrode of the triac. A voltage control circuit across the capacitor normally limits the voltage across the capacitor to an amplitude insufficient to trigger the diac and is operative in response to a manually actuated switch to increase that voltage, thereby triggering the diac and rendering the triac conductive to operate the motor for a selected time interval.