Abstract: The present invention is directed to a heat sink for a control device in an electric circuit of an automobile air conditioning system. The control device includes a power transistor which varies the amount of electric power supplied to a motor, so as to vary the rotational speed of the motor in response to demand. The motor drives a compressor of a refrigerant circuit in order to change the driving condition of the compressor in response to change in the rotational speed thereof. The power transistor is fixedly attached to an exterior surface of an evaporator which is the coolest element of the refrigerant circuit in order to provide cooling therefor. Thus, an excessive rise in temperature of the power transistor is prevented without impeding the flow of air in a duct which conducts air from the evaporator to a passenger compartment and without complicating the process of assembling the refrigerant circuit of the automobile air conditioning system.

Abstract: A device for detecting when a driven apparatus has frozen and/or its prime mover coupling mechanism is slipping. The rotational speed of the driven apparatus is detected and a corresponding speed signal is compared to a reference speed signal. The reference speed signal corresponds to a speed slightly lower than the idling speed of the prime mover. When the detected speed signal is lower than the reference speed single, slippage in the prime mover coupling mechanism is presumed and a slippage signal is provided. The slippage signal may be used to control the coupling mechanism to disengage the apparatus from the prime mover to prevent damage from occurring.

Abstract: A device for controlling an opening angle of an air mixing damper used in an automotive air conditioning system is disclosed. The device has an actuator for operating the air mixing damper and a blower for blowing the air. The device comprises an ambient air temperature sensor which is disposed on a front grill of an automobile for detecting the ambient air temperature at the exterior of the automobile and for providing a control signal, and a measuring circuit which computes the ambient air temperature data necessary for controlling the actuator and blower based on the detected ambient air temperature. The device controls the opening angle of the air mixing damper in accordance with the measured results.

Abstract: A device for detecting when a driven apparatus has frozen and/or its prime mover coupling mechanism is slipping. The rotational speed of a voltage generating alternator which is also driven by the prime mover is detected and a corresponding speed signal is compared to a reference speed signal. The reference speed signal corresponds to a speed slightly lower than the idling speed of the prime mover. When the detected speed signal is lower than the reference speed signal, slippage in the prime mover coupling mechanism is presumed and a slippage signal is provided. The slippage signal is used to control the coupling mechanism to disengage the apparatus from the prime mover to prevent damage from occurring.

Abstract: An audio frequency electromechanical vibrator comprising a flat plate permanent magnet magnetized in a predetermined direction and a coil wound around the permanent magnet for crossing the direction of magnetization. The permanent magnet and coil are fixedly disposed in a yoke which is elastically supported in a case through a spring plate. The case partly consists of a magnetic plate which is placed for opposing the permanent magnet to form a magnetic flux circuit, whereby the vibrator can generate a vibration corresponding to an audio signal applied to the coil.

Abstract: A capacity control device for a variable displacement compressor in a refrigerating or air conditioning system is disclosed. The capacity control device controls the operation of a variable displacement device having two variable displacement valves for changing the capacity of the compressor as a function of the required refrigerating capacity of the air conditioning system. The capacity control device determines whether the compressor should operate at a high, medium or low capacity. If the required refrigerating capacity is smaller than the current capacity of the compressor, the capacity control device actuates the variable displacement device to enable the compressor to operate at a lower capacity. If the required refrigerating capacity is larger than the current capacity of the compressor, the capacity control device actuates the variable displacement device to enable the compressor to operate at a larger capacity.