A pulse controller for controlling the energization and regenerative braking of a DC electric motor. An electronic switch connects the motor to a power source during motor driving and controls motor current during regenerative braking, the switch being rendered alternately conductive and non-conductive during both driving and braking and the ratio of conductive to non-conductive periods being controlled. The conductive and non-conductive periods are interrelated such that, regardless of the rati...

A garage door opener includes a radio receiver and a push button each operable to initiate a pulse for effecting a switching device which in turn energizes a latching relay. Operation of the latching relay completes an energizing circuit to the appropriate winding of a reversible motor which moves the door toward an open or closed position. A sensing circuit is operable for effecting the reversal of the latching relay to change the direction of motor operation in the event the door engages an ob...

A DC motor control circuit for providing improved starting and stopping control is provided. The control circuit includes a DC motor that is driven in response to an operating voltage applied thereto. A shunting element is adapted to define a current path in parallel with the DC motor to selectively shunt the operating voltage applied to the DC motor. A DC supply is provided for producing a DC signal, and a constant voltage supply circuit is coupled intermediate the DC supply and the parallel co...

Disclosed is an apparatus for controlling an electric motor for driving a cooling fan of an internal combustion engine. The apparatus comprises an engine operation detecting means, a timer, an engine temperature detecting means, a logical product generating means, and a motor controlling means. The electric motor is driven only when all of the following three conditions are satisfied: the engine is not operating; a predetermined timing period initiated when the engine stops operating has not exp...

A PNM (pulse number modulation) signal is generated in response to a DC signal the magnitude of which is in proportion to the detected rotational speed of an electric motor to regulate a period of time for which an electric power is fed to the motor by switching the electric power in accordance with the PNM signal. The switching frequency is arranged to vary depending on the variation of the load of the motor.

Apparatus for preventing damage to resistor grids in the propulsion controller circuit of a direct current motor, particularly of the type used in driving railway vehicles, in which a line breaker relay is de-energized whenever the propulsion controller fails to progress from the switch position to the full series position within 15-25 seconds. The line breaker relay remains de-energized for the duration of the power cycle of the propulsion controller and becomes operational automatically after ...

A control circuit for an electric vehicle traction motor having separate armature and field windings, includes an armature winding current control, a braking contact which is in series with the armature winding and which is closed or opened in accordance with whether motoring or braking is required, an alternative path being provided for motor current during braking, reversing switch means connected in circuit with the field winding, a field current control and logic circuit means arranged to op...

The shaft driven by a reversible motor for opening and closing a door is provided with at least one reflective surface. An optical source/detector senses rotation of the shaft and generates a pulse each time one of the reflective surfaces passes. A programmable counter circuit counts the pulses in one direction when the door is opened and de-energizes the motor when a predetermined count is reached without the use of mechanical switches. The counter is decremented when the door is closed, and de...

A circuit for electronically braking an AC motor. The circuit includes a controlled rectifying means for applying DC to the motor and a control means for turning the rectifying means on after deactuation of the motor for a timed interval determined by the charging rate of a timing capacitor through a variable resistance.

The invention provides snubbing apparatus for a D.C. motor in which a capacitor which is charged while the motor is rotating in a first direction is discharged into the gate of a thyristor to initiate the snubbing action. When the thyristor goes on a field coil is connected in series with the motor armature, so as to place the motor in a regenerative mode and snub the motor.