Abstract: This invention relates to motor speed control circuits employing capacitors. Two windings of a motor are connected in parallel to a neutral phase of an alternating current source. Each coil of the motor may be connected to the live phase of the source whereby the rotation direction of the motor may be altered. Three socket terminals are connected to each winding. A capacitor pack has three pins with two capacitors connected between a common pin and the two remaining pins. The pins of the capacitor pack can be inserted into the sockets in three different ways whereby either capacitor or the two capacitors in parallel can be connected across the windings to vary thereby the speed and performance characteristics of the motor.

Abstract: A remote speed controller for an electric motor, the controller comprising a switching unit having three switches. A capacitor pack incorporating two capacitors is connected to the switching unit such that different combinations of the capacitors can be selected by one switch. The controller is connected in circuit between an AC voltage supply and windings of a motor so that selective actuation of the one switch changes the speed of the motor in accordance with the values of the capacitors selected. Further switches are incorporated to provide reverse motor capability and remote sensor capability.

Abstract: This invention relates to DC solenoid actuator circuits.A DC solenoid winding located to act on an armature, is connected across a rectifier connected to an AC supply. A capacitor is provided across the winding so that the initial voltage applied to the solenoid winding is greater than the average actuating voltage.One terminal of the rectifier is connected to the AC supply via a switch which can either include in that circuit a capacitor or shunt that capacitor. The switch is mechanically linked to the armature of the solenoid winding so that at a predetermined point during the stroke of the armature the switch is operated to include the capacitor in the circuit so as to lower the actuating voltage for the solenoid.

Abstract: This invention relates to a ventilating fan of the kind comprising a housing defining an air passage, and an impeller rotatable from an electric motor or other prime mover within the housing.The invention is concerned with the provision of an improved automatic shutter device which consists of shutter plates which may have their pivot axes tangential to a common circle and movable between a position which closes the air passage and a position which opens said air passage. The shutter device is operated by means responsive to rotation of the impeller shaft for moving the shutter means to the open position when the impeller is rotating and to the closed position when the impeller is not rotating. The shutter operating means may be such that substantially no thrust or load is placed upon the prime mover when it is rotating at a selected operating speed.