Texas Instruments Corporation

Other

John R D'Entremont

Joseph G Nield, Jr

Matthew L Behler

Gordon S Swanson

Donald Tomkinson

Howard H Fraser, Jr

Radi Pejouhy

James C Wilson

Jan A Abcouwer

Louis C Beggs

Beggs, Louis C

Protection for an encased motor driven device is enhanced by utilizing additional sensors with associated resistance heaters to actuate the thermally responsive contacts of the internal line break. The sensors and heaters are powered from an auxiliary winding in the motor coils. When applied to a hermetic scroll compressor, the compressor can be protected against reverse rotation.

Internal protection circuit for electrically driven device

A motor protector having a can and internal electrical contact is hermetically sealed to a disk-shaped header of conductive material having a flattened edge for orientation during fabrication with spaced conductive pins sealed in and insulated therefrom. A heater-support with holes for fabrication is bonded to one conductive pin, a bimetallic element parallel to the axes of the pins having a contact element normally contacting the can contact. A heater without right angle bends is bonded to each of the electrically conductive pins, is spaced from the movable contact and rests parallel to the axes of the conductive pins. The motor protector is fabricated by providing a fixture having two depressions, one somewhat in the shape of the movable contact with upwardly extending pins for mating with the support apertures therein and the second for receiving the header in an upright position and adjacent the first. The support is placed on the fixture with the pins extending therethrough for support orientation. The header is then oriented in its fixture depression with one of the pins through the header resting against the support and is bonded to the support. The movable contact is then disposed in the proper depression and welded to the support. Slider brackets then receive the heater thereon and position it on the pins to which they are secured. The formed motor protector portion is placed in the cans and hermetically sealed thereto with the contact within the can disposed against the contact element on the movable contact member.

Hermetic motor protector

Electrical terminal pins (start, main and common) mounted in a glass header to provide electrical connection to a compressor motor are shown with a motor protector disposed on one of the pins in such a fashion that opposite-direction-oriented right angle female flag quick connectors are required for the start and main terminals, thereby avoiding the possibility of miswiring the terminal pins. The opening temperature of the motor protector is adjustable and the protector has a fail safe mechanism to avoid subjecting the motor to overtemperature conditions.

Plug-on protector for compressor motor

A motor protector having a can and an internal electrical contact is hermetically sealed to a disk-shaped header of conductive material, the header having a flattened edge for orientation in the can during fabrication of the protector and having spaced conductive pins sealed in and insulated from the header. A heater-support having holes for fabrication is bonded to one conductive pin, a bimetallic element on the support has a plane parallel to the axes of the pins and has a contact element normally contacting the can contact. A heater is bonded to each of the electrically conductive pins spaced from the movable contact and in a plane parallel to the axes of the conductive pins. In making the motor protector a fixture has one depression with pins mating with the support apertures and has a second depression receiving the header in an upright position and adjacent the first depression. The support is placed on the fixture with the pins extending therethrough and the header is oriented in its depression with one of the pins header resting against the support and is bonded to the support. The movable contact is disposed in its depression and welded to the support. Slider brackets receive and position the heater on the pins to which they are secured. The formed motor protector portion is placed in and hermetically sealed to the can with the contact within the can disposed against the contact element on the movable contact member.

A resettable, current-responsive, circuit interrupter device is made by blanking two wide but thin terminals and carrier stubs therefore, and embedding them up to a substantial part of their thickness in a side wall of an insulating housing so that sides of the embedded terminal portions are exposed from the housing material along the side wall inside the housing, so that terminal ends extend from the bottom of the housing to be connected in a circuit and through the top of the housing to be accessible for test purposes. An electrical contact is secured on an exposed side surface of one embedded terminal portion and a thermostatic strip element is secured to an exposed side surface of the other embedded terminal portion to extend closely along the one housing side to normally engage the contact in a very compact, closed circuit position of the device. The thermostatic strip element has a selected resistivity and the wide terminals have substantial current capacity so the thermostatic strip self-heats to a selected temperature to open the circuit in response to occurrence of a precisely predetermined overload current condition in the device circuit at any ambient temperature likely to be encountered in an automotive environment. The corner portions are then blanked from the terminals. A lid is disposed to overlie the thermostatic strip element.

Method for making a circuit interrupter device

A resettable, current-responsive, circuit interrupter device has two wide but thin terminals embedded up to a substantial part of their thickness in a side wall of an insulating housing so that sides of the embedded terminal portions are exposed from the housing material along the side wall inside the housing. Terminal ends extend from the bottom of the housing to be connected in a circuit and extend through the top of the housing to be accessible for test purposes. An electrical contact is mounted on the exposed side surface of one embedded terminal portion and a thermostatic strip element is secured to the exposed side surface of the other embedded terminal portion to extend closely along the one housing side to normally engage the contact in a very compact, closed circuit position of the device. A lid overlies the thermostatic strip element. The thermostatic strip element has a selected resistivity and the wide terminals have substantial current capacity so the thermostatic strip self-heats to a selected temperature to open the circuit in response to occurrence of a precisely predetermined overload current condition in the device circuit at any ambient temperature likely to be encountered in an automotive environment.

Circuit interrupter device and method for making

A motor protector having a thermostat metal element thermally coupled to an electrical motor in a refrigerator compressor motor system has a heater responsive to motor current thermally coupled to the thermostat metal element and has an improved component arrangement to provide locked rotor and ultimate trip protection for the motor without requiring calibration of the operating temperature for the protector after assembly or after incorporation in the motor system.

Protected refrigerator compressor motor systems and motor protectors

A miniature motor protector particularly suitable for low current applications has a generally rectangular parallelepiped configured metallic housing open at the top and has a bottom wall and side walls extending upwardly therefrom, the side walls having a flange forming a ledge portion at their free ends extending around all four sides. An electrically insulative gasket is disposed on the ledge with a lid having two discrete portions spaced from one another placed on top of the gasket. Extensions of the flange portions are bent over the gasket and lid to clampingly engage them. A heater element having two ends extends between the two portions of the lid with one end electrically and mechanically attached to one portion and the other end electrically and mechanically attached to the other portion. A first switch element is mounted on one of the lid portions and a second switch element is mounted on the bottom wall of the housing with one of the switch elements including a cantilever mounted snap-acting thermostatic member adapted to move into and out of engagement with the other of the switch elements upon selected thermal conditions of the thermostatic member.

Motor protector

A miniature motor protector device incorporates a flat, open-ended, electrically conductive metal can having a flange around its open end and having a terminal extending from the flange. A generally flat, electrically conductive metal lid is sealed to and electrically isolated from the can by an electrically insulating gasket which fits between the lid and the can flange. A thin electrically insulating film is disposed on the surface of the lid exteriorily of the can and a flat serpentine resistance heater element is positioned in heat transfer relation to the lid on top of the film. One end of the heater element is electrically connected to one end of the lid while the opposite end of the heater element extends from the opposite end of the lid to a second terminal. End portions of the lid and film are crimped over the heater element to secure the element and film to the lid. Two portions of the gasket are wrapped over respective opposite sides of the lid and portions of the can flange are crimped over the two gasket portions for securing the lid with its attached heater to the can. A thermally responsive bimetal member is mounted on the can bottom inside the can for movement in response to temperature change to engage and disengage an electrical contact on the inner surface of the lid for opening and closing an electrical circuit between the device terminals. The motor protector is particularly adapted for low cost, automated manufacture and for protecting a winding of a relatively small electrical motor.

Miniature motor protector

A combination starting and protecting device particularly useful with split phase motors such as those used with refrigeration compressors is disclosed in which an element of material having a positive temperature coefficient (PTC) of resistivity characteristic and a thermally responsive switch are disposed in the same housing. A thermal coupling of a preselected value between the PTC element and the thermally responsive switch is provided so that a desired reset or 'off' time is obtained for the thermally responsive switch without affecting the 'on' time.

Growing community of inventors

Foxboro, MA, United States of America

John R D'Entremont