US2435438A - Electric switch - Google Patents

Description

Feb. 3, 1948. J. FOWLER ELECTRIC SWITCH Filed June 19, 1946 PH/45E A PH/ISE 7 Ply/I55 C v T %3-%4 .IZIZBOOWOOQI...

.M mw r n ow r W m e t v A nn 1h w H Y Patented Feb. 3, 1 948 ELECTRIC SWITCH John Fowler, Stockport, England, assignor to Metropolitan-Vickers Electrical Company Limited, London, England, a British company Application June 19, 1946, Serial No. 677,650

, In Great Britain November 29, 1945 2 Claims. (01. 200-6) This invention relates to electric switches and more particularly to improvements in polyphase tap-changing switches.

Tap-changing switches are often used for varying the ratio of a transformer. In many arrangements of this kind there is a double-pole switch per phase in which the current is carried by one pole when the other is to be moved from tap contact to tap contact, and vice versa, so that taps may be changed without interrupting the circuit. Heretcfore, polyphase double-pole tapchanging switches have been relatively large because the twopolyphase poles have been mounted in tandem and this has also required an extra amount of equipment for operating the two poles in the necessary step-by-step or follow-up manner.

In accordance with this invention a polyphase multi-pole tap-changing switch is provided in which the different poles are operated by concentric rotatable driving means, thereby effectively halving the length or height of the switch and also making it possible to use a much more compact driving mechanism because this mechanism can then be mounted at one end of the switch.

An object of the invention is to provide a new and improved electric switch.

Another object of the invention is to provide a compact light-weight polyphase tap-changing switch.

The invention will be better understood from the following description taken in connection with g the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing Fig. 1 is a vertical sectional View of a switch embodying the invention, Fig. 2 is an enlarged elevation view of the outer of the two concentric operating members for the switch shown in Fig. 1, Fig. 3 is an enlarged elevation view of the inner of the two concentric operating members for the switch shown in Fig. 1.

Fig. 4 is a sectional View taken on line 4-4 of Fig. 1, and Fig. 5 is a circuit diagram of one of the phases of the switch illustrated in Fig. 1.

Referring now to the drawing and more particularly to Fig. 1, the switch is shown as comprising an insulating cylinder I. Mounted circumferentially in a transverse plane through the cylinder are a plurality of fixed contacts 2 and in an adjacent transverse plane is another set of fixed contacts 3, these two sets of contacts being in a zone around the cylinder which is assigned to one phase, say, for example, phase A of the switch. Similarly, there are sets of contacts 4 and 5 for phase B of the switch and sets of contacts 6 and I for phase C of the switch. For making selective contact with the circumferentially or circularly arranged sets of contacts 2, 3, 4, 5, 6 and 'I are respective movable contact arms 8, 9, II), II, I2 and I3. The movable contact arms 8, I0 and I2 are clamped relatively tightly to a tubuar member I4 of any suitable insulating material. As shown, the movable contact arms 8, I0 and I2 may be clamped to the tube I4 by means of screws I5. The tube I4 is mounted coaxially and preferably concentrically with the cylinder I. It is provided with three circumferentially extending slots I6, one of which is shown enlarged in Fig. 2. Mounted on the tube [4 are three slotted sleeves I! which are freely rotatable relative to the tube and one of these sleeves is shown enlarged in Fig. 2. The slots in the tube I4 and sleeves I! are in registration.

The movable contact arms 9, II and I3 are driven by a shaft I8 Which is mounted inside the tube I4. This shaft is provided with three slots I9, one of which is shown enlarged in Fig. .3, and a separate key 28 is inserted in each slot [9.

The contact arm 9, which is the same as the contact arms II and I3, is shown in enlarged sectional view in Fig. 4 and it will be seen that this arm has a cap 2| which by means of bolts 22 can be clamped tightly around the relatively loose sleeve H on the tube I4. The key 20 serves to interconnect the shaft I8 with the contact arm 9 through the slots I6 so that the movable contact arms 9, II and I3 will rotate simultaneously with the shaft I8.

The angular extent of the slots l6 corresponds or is at least equal to the angular distance between adjacent fixed contacts on the cylinder I.

The shaft I 8 is journaled at the bottom in a bottom plate 23 which closes the end of the cylinder ,I and both the tube I4 and the shaft I8 extend through a top web or plate 24, the shaft I8 extending slightly beyond the end of the tube I4. A Geneva gear 25 is mounted on the upper end of the tube l4 and a Geneva gear 26 is mounted on the upper end of the shaft I8. These Geneva gears are driven by a common driver 21 having pins or lugs which are disposed degrees thereon so that the shaft and the tube will be alternately rotated through the desired angular distance step by step in a followup manner. For example, the shaft I8 can first be rotated through the angular distance between is shown in Fig. in which the set of movable contacts 2 is connected to spaced points in a transformer winding 28 and the set of contacts 3 is connected to a different set 6f s acedtafi's for the winding 28.

and the rotatable contact arm} makes; electrical contact with a conductor 3!]. Conductors 29 and 30 terminate in contacts 3| and 32 respectively which are alternately engaged by a movable contact 32 of an arcing duty switch. As shown, current limiting resistors 33' and 34 are connected respectively between cdnductors 29-30 and intermediate fixed contacts 35 and 36 so that as the arm 32 is oscillated from one extreme to the other the current of the winding 281's first liir'iitd by the resistors as and 34, as the 'case may be, before the current is interrupted and alsb circulating current from a short circuit of electrically adjacent fixed contacts is controlled by" the resistance of resistors 33 and 34 iii series when the movable contact 32 is in its mid- Position.

With the sleeves H freely rotatable on the tube 14, and with the arms 5, H and i3 clamped tightly to the sleeves H, the relative movement will be between the sleeves l1 and the tube [4. The arms 9, II and I3 are actuated by the keys 2!) and the axial position of the armsS, H and I3 is maintained by the keys 20. Gbviously, however, this is not essential and it will readily occur to those skilled in the art that the sleeves I! can be fixedly attached to the tube l4 and the arms 9, II and E3 can be rotatably mounted on the sleeves l1. This has the advantage that the flanges shown on the sleeves H in Fig. 2 will then as the axial position of the arms 9, II and I3 and a larger area is obtained for the relatively moveable engaging surfaces.

While there has been shown and described a particular embodiment of this invention; it will be obvious to those skilled in the art that various changes and modifications can be made therein The rotatable- 8 makes electrical contact with a cnauetoi 29' without departing from the invention and, therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A polyphas'e multi fiol bet phase switch comprising, in combination, a rotatable shaft, a relatively rotatable sleeve on said shaft, a plurality of axially spaced circumferentially extending slots in said sleeve, separate rotatable contact arms relatively loosely mounted on said sleeve; separate eans extending through said att re; f'spctiviy attaching said arms to said shearer simultaneous rotation therewith, additional rotatable contact arms respectively axially adjacent'the first-mentioned contact arms, said additional contact arms being attached relatively rigidly to said sleeve for simultaneous rotation therewith, and respectively separate sets 'of cooperating fixed contacts for said" contact arms.

2. A three-phase double=cbntact finger ratio adjuster switch comprising, incombination, an insulating cylinder, separate sets 6! contacts dis"- posed circumfreiitially arounii'th'e iriside of said cylinder iii at least three different axially spaced hands; a rotatable contact carrying assembly mounted coaxially {if and; inside said cylinder, said assembly comprising a shaft inside a tube: iar sleeve, three contact arm's iiidunted qri said sleeve" idr rotationthe'rwith and for cooperatitiii res ectively with different ones or saiajt's or contacts, dirciimrerentianyextending slots iii said sleeve" respectively adjacent saia amtaet arias, additional contact arias indented said sleeve for relative rotation therewith, means extending through said slots for rotating said additional contact arms b means or said sharp, and means for alternately" rotatingsaid sleeve aha shaft through angles of the order of the circumier: e'nti'aliy extent of said slots; 1

JOHN FOWLER;

REFERENCES errnn" ,The following references are of record in the Number

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