GB2064230A

GB2064230A - Electric motor construction

Info

Publication number: GB2064230A
Application number: GB8035772A
Authority: GB
Original assignee: Sealed Motor Construction Co Ltd
Current assignee: Sealed Motor Construction Co Ltd
Priority date: 1979-11-14
Filing date: 1980-11-07
Publication date: 1981-06-10

Abstract

The terminations from the energising coils (12) of an electric motor stator (10) are directly connected to terminals (15-20) provided on a first component (14) attached to the stator. A second removable component (24) is provided with corresponding terminals (15A-20A) which mate with those of the first component so that the two components form a plug and socket unit. The terminals (15A-20A) of the second component are connected with other elements of the energising circuit such as power leads (28A, 29A) capacitor (35) and speed change switch (30, 52), the insulation of lead 48 may be pierced by a slot 47 in the upper part 42 of the socket. The bare end of lead 34 may be gripped by deformities 58 in a U-shaped connector 50. <IMAGE>

Description

SPECIFICATION Electric motor construction This invention reiates to electric motors, and more particularly to the making of connections between the wire coils of the motor and the supply leads and any external circuit elements, without the use of conventional cables.

The usual procedure in making such connections is to solder lengths of electrical cable to the ends of the stator wires, and then connect those cables to terminals or other external components. This is, however, extremely timeconsuming. The present invention seeks to provide a simpler method of making the connections, and of rationalising the design of electric motors in respect of the stator circuitry. UK Specification 1 522863 discloses the use of a molded plastics component mounted on the stator core and providing a number of electrical contacts to which the the stator wires can be connected without the use of solder. The external leads are then individually connected to these contacts. This still leaves the external circuitry to be made up in the conventional manner, and so only partially improves over conventional practice.

The present invention provides an electric motor having an energised stator whose windings have a number of external terminations, a first component of a plug and socket unit being secured relative to the stator and being provided with a number of terminals to which the wires of the stator windings are directly connected, and a second removable component of the plug and socket unit having terminals which mate with those of the first component and to which electrical power leads and other elements of the energising circuit are or can be connected.The terminals of the first component are preferably adapted to receive, retain and establish electrical contact with the stator wire without the use of solder or other externally applied bonding medium, as for example in UK Specification 1 522863, where each terminal comprises a conductive component having a slot into which the wire can be pressed and which narrows so as to grip the wire and break through any electrical insulation on the wire to establish electrical contact. Other elements of the energising circuit may comprise a switch incorporated in the second component for interconnecting stator coils in different ways via the mating terminals of the first and second components to provide different motor speeds.In the case of an induction motor, the other elements of the energising circuit may include a capacitor connected to terminals in the second component.

In order that the invention may be more clearly understood, one embodiment will now be described with reference to the accompanying drawings, wherein: Fig. 1 shows a stator for an axial gap motor with a plug and socket assembly, Fig. 2 shows a cross-sectional side view through the plug and socket components in use, Fig. 3 shows a detailed cross-sectional view of two terminals in the plug assembly, Fig. 4 shows an underside view of the plug, Fig. 5 shows a diagrammatic plan view of the plug and socket unit as incorporated in the stator energising circuit, and Fig. 6 shows an exploded perspective view of a socket terminal.

Referring to the drawings, and firstly to Fig. 1; the stator for the axial gap motor has an annular laminated core 10, with slots in one face, into which slots are placed the energising coils 12. A socket assembly 14 is securely mounted to the end of the stator core remote from the rotor (not shown). This socket can suitably be secured in that position by adhesive or by screws. The socket assembly has a number of terminal sockets 1 5, 16, 17, 18, 19, 20 projecting upwardly from the molded plastics body 22 of the socket assembly, and to which the wires of the stator coils are directly connected. A removable plug assembly 24 has a moulded plastics body 26 from the underside of which project metal terminal pins 15A, 16A, 17A, 18A, 19A, 20A, to connect with respective terminal sockets of the socket assembly.The plug assembly is provided with conventional line terminations 28, 29 for connection with the power supply leads 28A, 29A. It also incorporates a switch having a manually operable knob 30. Two terminals 31, 32 are provided in the plug assembly to receive the wires 33, 34 respectively from a capacitor 35.

Referring also to Figs. 2 and 6, the sockets 1 5 to 20 are of plastics material and integrally moulded with the body 22. Each socket is of rectangular configuration in plan and has slots 40 in two opposite side walls, the slots extending downwardly from the upper edge of the socket.

Within each socket is located a terminal 42 made of sheet copper or other metal. The terminal is of generally U shape, having two opposite side walls 43, 44 joined by a base 45, the top edge of the side wall 44 being turned over as a flange 46 downwardly inclined towards the opposite side wall 43. A slot 47 extends across the base 45 and some distance up the side walls 43, 44 and tapers upwardly in the side walls. A wire 48 from the stator is laid in the slots 40 of the socket 20, as shown in Fig. 6, and the terminal component 42 is then pressed fully down into the socket. In so doing, the wire which extends across the socket is received in the slot 47 and is pressed into the tapering upper portions of the slot in the side walls 43, 44 so that the wire is gripped thereby and the insulation of the wire is broken, thereby establishing electrical contact with the terminal.

Referring now to Figs. 2 to 4; in the plug assembly, the terminal pins are similarly made from sheet metal, each comprises an inverted Ushaped portion which is a resilient push fit into a corresponding moulded opening in the underside of the plug body. In the case of the terminal pins 15A, 16A, 17A, 18A, the top surfaces of the inverted U-shaped portions are exposed at the top surface of the plug body 22 to provide wiping contacts for a generally T-shaped metal plate 52 secured to the underside of the switch knob 30.

The leg of the T-shaped plate makes contact selectively with the terminal pins 15A, 16A, 17A.

in alternative conditions of the knob 30, while the head of the plate makes contact with the terminal pin 1 8A in all three positions. Thus, the terminal pin 1 8A is connected selectively with any one of the terminal pins 15A, 16A, 17A. The sheet metal component of the terminal pin 1 7A is further extended at 54 along the underside of the plug body for connection with the line terminal 28. A screw 56 clamps the end of the power cable to the end of the metal strip 54. Figs. 3a and 3b show the terminal pins 1 9A, 20A respectively.The metal terminal pin 1 9A is provided with an extension strip 55, similar to the strip 54, which connects with the terminal 29.The tops of the inverted U-shaped portions 50 of the terminal pins 1 9A 20A are exposed at terminal openings 31 32 in the top surface of the plug body, and are provided with registering openings, so that the ends of the cables 33, 34 from the capacitor 35 can be pushed through from above into the inverted U-shaped portions 50 of the terminal pins. Inwardly deformed elements 58 in the Ushaped portions 50 receive and grip the cable ends to establish electrical contact therewith.

When the plug assembly is mated with the socket assembly, the pins 15A to 20A slide into terminals 42 of the sockets 15 to 20, and are gripped between the side wall 43 and turned over flange 46 of each socket terminal. The resulting stator circuitry' is shown in Fig. 5. The stator coils comprise a main winding 1 2A connected between the terminals 18, 1 9 and an auxiliary winding 1 - connected primarily between the terminals 1 5 and 20, but with intermediate tappings to the terminals 1 6 and 1 7. Thus, rotation of the switch 30 provides different effective auxiliary windings, which provides different motor speeds.

Instead of manually operated switch, terminals similar to the terminals 31, 32 could be provided in the plug body from other terminal pins, for connection with, for example, external automatic control equipment.

As can be seen, during the construction of the motor, the stator wires can be connected quickly, simply and directly to the terminals of the socket assembly without the use of solder or other bonding medium, and indeed the process of inserting the wires in the sockets and then inserting the socket terminals 42 can be completely automated. The plug assembly can be manufactured separately, and it is again a simple, inexpensive construction which can be easily replaced if it goes wrong, or if alternative external circuitry is desired. In the case of an axial gap motor, moreover, the entire auxiliary circuitry can be mounted to the plug assembly and fitted to the end of the stator housing instead of the more usual mounting of components to the side of the housing. This is particularly useful in the case of motors used in glandless circulating pumps, where side-mounted components often interfere with the installation of the pump, particularly the connection of the pipe unions.

Claims

1. An electric motor having an energised stator (10) whose windings (12) have a number of external terminations (48) which are directly connected to terminals (15-20), carried by a component (14) secured relative to the stator, characterised in that said component (14) is the first component of a plug and socket unit, a second removable component (24) of which has terminals (1 5A-20A) which mate with those of the first component and to which electrical power leads (28A, 29A) and other elements (30, 52; 35) are or can be connected.

2. An electric motor according to claim 1 wherein the second component (24) incorporates as one of said other elements a switch (30, 52) for interconnecting stator coils (12A, 12B) in different ways via the mating terminals (15-20; 1 5A-20A) of the first and second components to provide different motor speeds.

3. An electric motor according to claim 2 wherein terminals (1 5A--18A) of the second component are metal elements which extend from one side of the second component at which they are presented for mating with the corresponding terminals (15-18) of the first component, to another side of the second component at which they are exposed for wiping contact by a movable conductive component (52) of the switch.

4. An electric motor according to any of the preceding claims wherein the second component (24) has a capacitor (35) for the motor connected with the motor via terminals (19A, 20A, 19, 20) of the first and second components.

5. An electric motor according to claim 4 wherein terminals (1 9A 20A) of the second component are metal elements which extend from one side of the second component, at which they are presented for mating with the corresponding terminals (19, 20) of the first component, to another side of the second component at which they are exposed (31, 32) for connection to leads (33,34) from the capacitor.

6. An electric motor according to claim 5 wherein said capacitor terminals (1 9A, 20A) of the second component are sheet metal elements formed with inverted U-shaped portions (50) the apexes of which are provided with openings exposed (31, 32) at said other side of the second component to receive the capacitor leads, the Ushaped portions having inward projections (58) to grip the ends of the leads and establish electrical contact therewith.