Texas Instruments Corporation

Walter T Sutton

Stanley F Kummer

James B Sims

Randy Craft

A pressure sensor probe has a first port connectable to a relatively low pressure source in a compressor crankcase and a second port connectable to a relatively high pressure source at the output of an oil pump. A shuttle is slidably disposed in a bore and has a first end which closes the first port when the difference in pressure between the two ports indicative of normal operation exceeds a selected value determined by the relative areas of the shuttle exposed to the respective pressures and by a coil spring which biases the shuttle away from the first port. A passage is formed between the shuttle and the bore leading from the second port to a force receiving surface on the high pressure side of the shuttle. The length and cross sectional area of the passage is selected to provide a desired dampening or time delay between the high pressure source and the force receiving surface. A control circuit includes a reed switch whose state of actuation is dependent upon the position of the shuttle. The control circuit processes the input signal from the reed switch to control the energization of the compressor motor.

Control circuit particularly adapted for use with lubrication sensor

A motor protector for a split-phase motor having a starting switch, the arm of which is connected to the run winding and which moves from a first position in engagement with a first contact to energize the start winding into a second position in engagement with a second contact thereby to deenergize said start winding upon the motor attaining a predetermined starting speed. The protector includes a thermostatic element to be positioned in heat-exchange relationship with the motor windings and which is heated by the flow of electrical current therethrough. It has a first curvature position at ambient temperatures and moves to a second curvature position at an elevated predetermined temperature. The protector further includes a switch having contacts which are opened in response to movement of the thermostatic element into its second curvature position. The thermostatic element is serially connected with the contacts of the latter switch in a circuit between one terminal of an a.c. power source and the switch arm, and the thermostatic element is shunt-connected across said switch arm and the aforesaid second contact. While the motor is operating below its starting speed, the thermostatic element is responsive to motor overcurrent conditions that cause self-heating of the element to the elevated predetermined temperature thereby to open the contacts of the switch and deenergize the motor windings. While the motor is operating at speeds in excess of its starting speed the motor current is shunted around the thermostatic element and is responsive to its temperature rising above the pedetermined elevated temperature substantially as a sole function of the motor winding temperature thereby to move into its second position and open the switch contacts to deenergize the motor windings.

Motor protector

The disclosure relates to a system and method whereby bimetallic discs as well as a completed thermostat can be dynamically tested non-destructively. The bimetallic disc can be tested by utilizing its magnetic properties, the magnetic properties of the disc being sensed by a magnetic transducer under operating conditions to provide a velocity curve of disc movement. The thermostat is tested in the same manner as the disc with simultaneous monitoring of the electrical switch controlled by the disc to insure operation thereof at the ideal point on the disc velocity curve.

Disc thermostat test system and method

A color television receiver having degaussing coil means which are energizable by an alternating current source and which are disposed in demagnetizing relation to magnetically permeable materials in receiver components such as the receiver picture tube is shown to include resistor means of positive temperature coefficient of resistivity in series with the degaussing coil means. The resistor means are self-heating when energized and display progressively increasing resistance as resistor temperature increases, the resistor means further displaying a sharp or anomolous increase in resistance when resistor temperature increases to a selected level. Preferably, relay means responsive to this increase in temperature of the resistor are connected in parallel with the degaussing coil means to shunt the degaussing coil means as resistor temperature increases to said selected level. The receiver circuit is arranged so that each actuation of the receiver from a cold start energizes the degaussing coil and resistor means to establish a magnetic field, subsequent heating of the resistor means progressively reducing degaussing coil current to reduce the magnetic field to substantially zero in a cyclical manner, thereby to demagnetize the receiver picture tube. Where used, the relay means respond to increase in resistor temperature to said selected level to shunt the degaussing coil means after the picture tube is demagnetized. A relay which incorporates the resistor means, relay contact means movable in response to resistor temperature, and appropriate terminals for connecting the relay in a television receiver circuit is also shown.

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Lexington, KY, United States of America

Walter T Sutton