A system for controlling the position of a four-position rotary valve from a remote location, for example, in an airplane. A manually operable, single-pole, multi-throw switch supplies a voltage to a selected one of a plurality of normally closed limit switches via a selected one of a corresponding plurality of contacts of the manually operable switch with which the pole thereof is engageable. A motor then drives a cam and the valve until the cam opens the said one limit switch. The valve is then located in a position corresponding to the said selected contact. A relay is employed to energize the motor. An electromagnetic motor brake is energized at the same time the motor is energized. When the brake is energized, the motor output shaft is free to rotate. When the brake is deenergized, the motor output shaft is locked.
A solid state circuit for sequencing a valve mechanism from its normal operating position through a sequence of cycles to blow down various different lines of the network to which the valve mechanism is connected. The circuit may be set to initiate its sequence at one of a number of time periods such as once a day or once a week. Once initiated, the circuit operates a motor drive for the valve mechanism continuing for a timed interval followed by a delay or dwell at each blow down position. A signal is provided to indicate that the circuit is about to enter a blow down sequence followed by the sequence itself. Various alarms and safeguards are provided for the sequence.
A four way valve assembly for a reversible cycle refrigeration system in which a rotary valve accomplishes the switching between heating and cooling modes. The rotary valve is mounted in a cavity in a housing and is designed to be rotated by a unidirectional electric motor. The rotary valve comprises a plate having a pair of recesses in it, which each acts to connect a pair of ports in a base plate together. A high pressure bypass port maintains the pressure in the cavity at a relatively high level such that the high pressure tends to increase the abutting contact between the valve plate and the base plate. A cam and switch arrangement provides the necessary control to stop and start the electric motor.
A rotary tap changer or switch is rotated by a motor to a plurality of contactor positions by a control system having a cam that rotates to activate limit switches respectively corresponding to contactor positions. The activation of the limit switches causes operation of a relay which, after a selected time delay, operates to discharge a capacitor across the motor to apply dynamic braking and stop the motor. When starting the motor to rotate the tap changer, energization is applied through the limit switches to select rotation in a forward or reverse direction determined with some modification by the shortest distance of rotation to the new selected position.
A damper blade control for regularing the flow of conditioned air through a supply air duct and into a zone. The control comprises an electric motor for use with a source of electrical energy for moving the damper blade between a minimum air flow position and a maximum air flow position, and a thermostatic switch electrically positioned between the motor and the source of electrical energy for connecting the motor thereto to change the position of the damper blade in response to changes in the temperature of the zone. The control further comprises maximum and minimum flow switches disposed outside the supply air duct for disconnecting the motor from the source of electrical energy when the damper blade reaches, respectively, the maximum and minimum air flow positions. An indicator lever is located outside the supply air duct and supported thereby for movement in response to movement of the damper blade for indicating the position thereof, and the indicator lever actuates the maximum and minimum flow switches to disconnect the motor from the source of electrical energy when the damper blade reaches, respectively, the maximum and minimum air flow positions. Adjustable securing brackets are provided to adjustably secure the maximum and minimum flow switches to the supply air duct, the position of the maximum and minimum flow switches being adjustable to vary the maximum and minimum air flow positions of the damper blade.
A control system is provided for controlling a flue damper in a furnace flue. The control system includes a voltage source, a thermostat, a gas valve, and means for moving the flue damper between a closed position and an open position. The moving means includes a timer driven by a motor with a specially wound coil assembly including a first winding and a second winding. The coil assembly further includes a first terminal, a second terminal and a center tap terminal. The control system manipulates the flue damper and heating system during three stages of operation. The flue damper is closed and the furnace is off at the beginning of stage one. The control system opens the flue and turns on the furnace during stage one. The flue damper remains open during stage two. The control system turns off the furnace and closes the flue damper during stage three.
