Abstract: A reversible electrically driven motor is disclosed together with circuitry for controlling the direction of the motor such that the current to the drive motor cannot be reversed to an opposite direction while the motor continues operation in a first direction. Once the motor slows to predetermined speed, which may approximate near-stop condition, the circuitry permits the voltage to operate in the opposite direction thereby reversing the motor. The control apparatus may include the portion of the electric motor which operates as a generator when the motor is not being electrically driven, a solid state sensor for sensing the voltage generated, and a lock-out circuit which responds to the sensed voltage to disable the operation of the driving circuit which reverses the motor.

Abstract: A reversible d-c motor, driving a load such as a vehicular radio antenna, has its armature winding connected in a transistorized energizing circuit which is activated by a start circuit and locks operated as long as the motor speed surpasses a certain threshold, i.e. until a major obstacle or a terminal position is encountered. The threshold may be determined by a voltage sensor detecting the counter-e.m.f. induced in the armature winding, by a Hall-effect device in the magnetic field of the stator, or by a speed sensor. The armature winding lies in series with a current limiter which determines the maximum torque applied to the load and may also transmit a no-load signal to a protective circuit when the motor is found idling, the protective circuit including a timer which cuts off the motor after a predetermined idling period. Alternatively, the operating period may be determined by a pulse counter de-energizing the motor after a preferably settable number of rotor revolutions.

Abstract: In the main intended application of the arrangement according to the invention, that is, using a reversible motor compressor in a heat pump in a refrigerating or air conditioning system, it is desirable to insure a delay during reversal of the direction of compressor operation. A control arrangement is provided in which the control system controls the direction of motor operation or compressor capacity in accordance with temperature conditions, the system including control means for effecting operation in a low capacity direction or condition, or alternatively in a high capacity direction or condition in response to one set, and another set, respectively, of temperature conditions and with timer means delaying a restart of the compressor motor for at least a predetermined time in response to a condition of the control means operative to initiate a change in the operating direction or condition of the compressor when it restarts.

Abstract: Control device responding to current changes in a load circuit including a supervisory circuit carrying a current proportional to the current in the load circuit, a transformer coupling the supervisory circuit to the load circuit, and an overcurrent sensor and an overcurrent relay electrically connected in series in the supervisory circuit. The overcurrent sensor being set to deliver a signal when a given first current value is reached after a response delay, the overcurrent relay being able to interrupt the load circuit if a given second current value is reached after an adjustable response delay, and a method of operating the control device in a waste crushing machine.

Abstract: A motor switching and control circuit is disclosed in which the direction of transport of web material transferred between two reels is reversed by detecting a condition requiring reversal, generating a reversing signal in response to the detected condition, and switching the direction of rotation of an AC motor in response to the reversing signal. Both motor direction switching and reversing condition detection switching are accomplished at substantially zero motor current flowing through and zero motor voltage across the contacts of any circuit switches, thereby eliminating radio frequency interference and logical noise generation during switching. The circuit is particularly useful in connection with the ribbon control drive in an impact printer such as a matrix printer.

Abstract: A control circuit for an electrically driven vehicle has contactors for determining the direction of operation of the motor, but these contactors cannot be operated until the current flowing through the motor is below a predetermined level.

Abstract: A control device for an electric fan comprising a power supply, a control means, a trigger pulse generator and a switch means, all connected in circuit with the motor of the electric fan, wherein the trigger pulse output of said trigger pulse generator is connected to trigger said switch means and is controlled through said control means to thereby achieve a stepless, variable speed control for the electric fan. Other forms of the device may further comprise a delay means, and/or delay reverse means, and/or wave generator means and/or any combination thereof, connected in the above circuit to accomplish stepless speed reduction and/or delay speed-down reverse and/or various kinds of imitative natural wind rotational speeds for the electric fan.