Abstract: Disclosed is a monitoring circuit responding to different operational conditions of an electric motor. The circuit includes a measuring resistor connected in series with the stator winding of the motor to produce an actual load value signal. The actual value signal is applied to one input of a comparison circuit whose other input is consecutively supplied with three different nominal reference voltages corresponding to principle operational conditions of the motor, namely to the starting phase, to the normal operational phase, and to an overload. The source of the variable reference voltage includes switching transistor cooperating with a timing member and with voltage dividers adjustable from zero to a maximum nominal voltage value corresponding to the power supply voltage.

Abstract: In this control box, a first switching device (R-1) is actuated when the operator acts on a selector (1) whereby he can choose, on one hand, the direction of the driving of the motor (9) and, on the other hand, by means of a brief or prolonged action, the driving speed of this motor. If the action is prolonged, the switching device (R-1) is inhibited by a second switching device (R-2) controlled by a timing circuit (27) which was initiated at the start of the action. This second switching device then supplies power to the motor (9) through a series resistor (18) so long as the selector (1) is actuated. Application in an electric window raiser of an automobile vehicle.

Abstract: A motor for operating the door is controlled for forward and reverse rotations and stoppage by a control circuit responsive to an operation command signal, an upper-lower limit signal, an obstruction detection signal and a maximum drive time over signal, thus controlling the door stepwise for opening, stoppage, closing, stoppage and opening in that order. Upon generation of an obstruction detection signal or a maximum drive time over signal during the closing operation, the control circuit controls the motor in a manner to open the door for a certain period of time, and subsequently upon application of an operation command signal, the control circuit is set in a manner to open the door again.

Abstract: An electric pulse-controlled unit for a window raiser designed especially for use on an automobile, including a motor to raise and lower the window, a power circuit to activate this motor, a motor control capable of being moved from a cutoff position into first and second active positions in which the motor is activated respectively to raise and lower the window, and a mechanical control switch enabling selection of one of the active positions in order to operate the motor in the desired direction. Between each active position of the mechanical control switch and the power circuit for controlling the motor for raising and lowering the window, there is provided two circuits in parallel, each having a control flip-flop with a respective reset input connected in parallel by means of an OR logic circuit to a set of circuits comprising in particular: a delay circuit, a double control detection circuit, and a voltage loading detection circuit.

Abstract: A timer-controlled speed changing device for electric fans comprising a timing switch operatively connected to a first speed changing circuit and a second speed changing circuit, for changing the speed of an electric fan from a pre-set speed with the first or second speed changing circuit to another pre-set speed with the second or first speed changing circuit after a predetermined time period set by the timing switch.

Abstract: A windshield wiper motor control circuit for controlling a motor which is normally operated in either continuous or intermittent modes and wherein during the intermittent mode the motor is responsive to a voltage source controlled by a pulse generator. In response to low motor speed and voltage conditions and during overload conditions, the control circuit reverts to intermittent operation and the duration between pulses is adjusted to prevent overheating or destruction of the motor.

Abstract: To reliably turn OFF a pulse-controlled thyristor in series with a battery supplied motor circuit, in case of malfunction of the control circuit, or even of the supervisory circuit itself, the voltage across the thyristor is sensed and, if an ON condition of the thyristor, as represented by sensed voltage, is determined while the pulse source does not provide an ON command, a disabling control signal is applied to the pulse source to provide an OFF command; in case of failure of the sensing element, an additional voltage is supplied, through a time delay circuit to the disabling input. Time delay circuits are interposed between the respective sensed signal and command signal and applied through a logic circuit to prevent spurious operation of the monitoring and safety circuit.

Abstract: A solid state electronic circuit for protecting a single phase induction motor against excessive loading by comparing motor start winding voltage with motor source voltage is disclosed, wherein the circuit automatically removes the motor from its driving source upon the occurrence of such excessive loading. An additional feature includes comparing start winding voltage with source voltage to remove the motor from its driving source upon the occurrence of excessive start winding voltage and corresponding excessive high motor speed. A motor starting circuit to permit the start winding voltage to rise to its normal running level and a time delay restarting circuit to permit the motor to automatically restart after elapse of a selected lock out period following removal of the motor from the source due to insufficient or excessive loading is also provided.

Abstract: A step structure for mobile homes and the like. A base is secured to an underside of the vehicle and serves to pivotally mount a linkage which in turn carries a pair of step rails on which a step is slidably mounted. Extension and retraction of the step involves combined swinging travel of the step surface as well as travel in a lateral direction along the step rails to achieve a highly accessible step location well outward of the vehicle side. An electrical control system electronically limits motor operation to avoid motor burnout in the case of step obstruction.

Abstract: A three-phase motor system is described incorporating a small fractional horsepower three-phase control motor that is connected to rotate in a predetermined direction when a three-phase drive motor is rotating in a predetermined direction. A plurality of microswitches having actuating arms with cam follower portions are mounted with the arms contacting a cam plate. When the system is energized, the cam plate is rotated to open the microswitches if the rotation of the fractional horsepower motor is reversed. The microswitches, when opened, de-energize the fractional horsepower motor and concurrently prevent the closure of a solenoid-operated start switch to prevent energization of the drive motor.