Abstract: Bulk and accessibility problems in a motor control unit for installation in a motor control center are eliminated in a unit having a housing (10) in the shape of a rectangular solid and provided with a top wall (14), a bottom wall (16) spaced from the top wall (14), a rear wall (12) and a front (20). A plurality of motor control instrumentalities (24), (26), (36) are located within the housing (10) and are mounted to at least one of the walls (12), (14), (16) in close proximity to the rear wall (12). A side wall (22) is located to one side of the top, bottom and rear walls (12), (14), (16). A pivot (78) mounts the side wall (22) for pivotal movement about an axis generally parallel and in proximity to the rear wall (12). A disconnect switch (104) is carried by the side wall (22) to be disposed in the housing (10) in one position of movement of the side wall (22) relative thereto and a partial front wall (80) is provided for the housing and carried by the side wall (22).

Abstract: The problem of providing plurality of different models of pressure switches to suit the requirements of a plurality of differing manufacturers may be minimized or eliminated in a pressure switch, including a frame (20), a diaphragm (50) secured to the frame (20) and adapted to be exposed to a mechanical source of fluid under pressure, such as a compressor, and electrical contacts (64), (66), (70) mounted on the frame (20) for relative movement toward and away from each other between open and closed positions. A lever system (72), (80) is mechanically interposed between the diaphragm (50) and the contacts (64), (66), (70) for effecting the previously mentioned relative movement and an unloader valve (110) is mounted on the frame (20) and adapted to be connected to the source of pressure fluid and operable when the contacts (64), (66), (70) are in an open position to vent fluid under pressure from the source.

Abstract: The cutting or crushing of electrical wire during a tang termination process is avoided by the method that includes the steps of providing a post (28) of a thermoplastic material in adjacency to a terminal mounting structure (22, 24) wrapping an electrical conductor (34, 40) forming part of the winding (20) around the post (28), mounting a metal terminal (42) having a tang (52) on the mounting structure (22, 24) so that the tang (52) extends at least partially about the post (28), and closing the tang (52) about the post (28) with sufficient heat to destroy the insulation, if any, on the electrical conductor and establish a fused electrical connection between the tang (52) and/or terminal (42) and the conductor (34, 40).

Abstract: The cutting or crushing of electrical wire during a tang termination process is avoided by the method that includes the steps of providing a post (28) of a thermoplastic material in adjacency to a terminal mounting structure (22, 24) wrapping an electrical conductor (34, 40) forming part of the winding (20) around the post (28), mounting a metal terminal (42) having a tang (52) on the mounting structure (22, 24) so that the tang (52) extends at least partially about the post (28), and closing the tang (52) about the post (28) with sufficient heat to destroy the insulation, if any, on the electrical conductor and establish a fused electrical connection between the tang (52) and/or terminal (42) and the conductor (34, 40).

Abstract: A self-powered multiple phase cirucit protection device including a plurality of current transformers (16, 18, 20) connected and parallel with each other and adapted to be individually associated with one phase (10, 12, 14) of a multiple phase load and for providing signals I.sub.a I.sub.b, I.sub.c representing the current flowing in an associated phase. A switch (62) is adapted to be actuated to interrupt power to the multiple phase load and a fault determining circuit (45) is connected to the circuit transformers (16, 18, 20) and to the switch (62) for actuating the switch (62) for at least one predetermined condition of the current signals I.sub.a, I.sub.b, I.sub.c. A power supply (34) is provided for the fault determining circuit (45) and has an input connected to all of the current sensors and an electrical clamp (36) is connected to the power supply input.

Abstract: The manufacture of an electrical contactor is simplified by a construction including a base 22, a contactor assembly 20 including at least one movable contact 32 mounted on the base, a magnetic core 26 mounted on the base 22 in proximity to the contactor assembly 20, and a bobbin 28 mounted on the magnetic core 26 and having spaced flanges 112, 114 defining a peripheral winding receiving recess 118 wherein the flange 112 has terminal receiving recesses 122 in an edge 120 thereof. Metallic pins 132 have one end captured in the edge 120 and receive the ends 164 of an electrical winding on the bobbin 126 in wrapped around fashion. A plurality of metallic terminal pieces 128 are provided, one for each of the recesses 122 and include a finger 156 crimped about the corresponding pin 132 and the winding end 164 wrapped thereabout.

Abstract: Disconnection of a fluid conduit from a fluid fitting 38 and electrical conduit from apertures 28 in a fluid pressure sensing switch when servicing is required is avoided in a construction wherein a switch module 12 is secured to a base 10 mounting a fluid pressure receiving fitting 38 and electrical conduit receiving apertures 28 by only two threaded fasteners 24, allowing the module 12 to be separated readily from the base 10 without disturbing conduit connections.

Abstract: An electrical contactor including a generally U-shaped base 12 having a bight 44 and parallel upstanding legs 22 terminating in mounting flanges 50, a contactor assembly 10 including an insulator 28 abutting the flanges 50 and having a movably mounted electrical contact 22, and a plastic shell 14 disposed between the legs 42 and sandwiched between the bight 44 and the insulator 28. A magnetic core 16, an electrical coil 48 and an armature 20 are included in the assembly.

Abstract: A pressure switch including a housing 10, electrical contacts 16, 24 within the housing and a lever 26 movably mounted within the housing and operable to effect relative movement between the contacts. A biasing spring 70 biases the lever in a first direction and is settable through elements 74, 76, 78, 80 to determine the pressure level at which the switch will operate. An over center device 36, 38, 40, 42, 44, 46, 50, 52, 54, 56, 58 is located within the housing and is connected to the lever to provide snap action movement of the contact. A pressure port 96 is located in the housing and a fluid motor including a rolling diaphragm 116 is in fluid communication with the pressure port and acts in opposition to the biasing spring 70.

Abstract: A pressure responsive switch includes a diaphragm exposed to a pressure source and operating combination of levers to open and close a switch at predetermined pressure values. To prevent operation of a pump motor at abnormally low values, an element is provided between the diaphragm and the switch operating means to open the contacts.

Abstract: A pressure switch incorporates a pressure gauge in which the indicator actuator is operatively connected to an element movable in response to pressure variations in the system being monitored, which element is also part of the switch operating mechanism.