US1532081A - Electric switch - Google Patents

Description

arch EL 11925 W. K. RANKIN ELECTRIC SWITCH Filed Nov. 1 1922 2 Sheets-Sheet l Invemtwt .William Kfiankin 3 b3 HisAttmrneg.

w. K. RANKIN ELECTRIC sw wcu FildNov 14s. 1922 2 Sheets-Sheet 2 Fig. 5a

Ihvevwtor:

His Attorn eg Patented Mar. El, 19250 cairn sira WILLIAM K. RANKIN, 0F SCHENECTADY,'NEW YORKJ'ASSIGN OR TO GENERAL ELEC- TRIS COMPANY, A CORPORATION OF NEW YORK.

. nnno'rniea SWITCH.

Application filed N ovember le, 1922. Serial No. 600,804.

To all cello m. it-ma l concern:

Be it known that I, WILLIAM K. RANKIN, a citizen of'the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

My invention relates to electric switches,

and especially to switches having contacts separable within a closed chamber --which contains an insulating liquid.

In theoperation of fiuid break switches, the-arc drawn between the switch contacts upon their separation produces intense local heating of the insulating liquid ambient the arcpath thereby vaporizing a part of.

this liquid and creating within the cham her a pressure which'operates both to suppress the arc and to accelerate the separation of the contacts by its piston action on the movable contact.

One of the major objects of my invention is to provide at switch ofv the above described type wherein a certain amount of liquid may be used repeatedly during circuit breaking operations, provision being made for the recovery of this liquid after each operation so that the same may be used again. To this end in the embodiment of my invention. herein disclosed, I provide a receptacle having a reservoir in its lower portion adapted to contain a small quantity of liquid which is one such as water that is not-permanently affected by heat. l llectrodes are able beneath the surface of this liquid and the portion of the receptacle above the sump is formed as a condensing chamber whereby the liquid vaporized by the arc is condensed after the arc has been extinguishcd and returned to the sump.

i In order to facilitates its cooling and condensing action and to insulate the conducting portions thereof, I submerge the receptacle in an insulating liquid which also. surrounds the main contacts of the switch.

Numerous other objects and advantages of my invention will be in part obvious and in part explained in the following description taken .in connection with the accompanying drawing in which Fig. 1 shows a vertical section of a single pole switch containing one embodiment of my invention,

provided which are separ some of the parts being cut away and others shown in elevation. Fig. 2 is a sectional view of a modified form of receptacle or explosion chamber wherein additional strength is attained by imbedding rings of metal the chamber is formed, carebeing taken to maintain a suflicient dielectric strength of insulation between contacts, and Fig. 3 is a view similar to Fig. 1, showing a modified form of switchfor use on high power circuits, where the intensity of the arc and :the amount. of vapor formed will cause a l'ngh pressure to be exerted against the walls of the explosion chamber, the construction of the chamber being such as to necessitate a modified arrangement for the insulation of the contacts.

.In Fig. 1 is shown a tank adapted to contain an insulating liquid and in which rests an insulator 12 adapted to support a contact 13 and an explosion chamber casing 14. The explosion chamber casing 14 is composed of insulating material, the inner surface of which is corrugated, thereby forming small annular condensingchambers 15. The stationary electrode 16 is cupshaped and forms the lower portion or sump of the explosion chamber.

The cover 20 of the tank 10 is constructed to permit the passage of the insulating operating rod 21 and also the insulating bushings 22 through which the switch leads 23 and 24 pass. The switch lead 24 is hollow in form and is fitted with a side connection and -a stopcock 25 to which means may be attached to admit liquid 26 to the explosion chamber. The normal levels of the liquid in tank 10 and explosion chamber 14 are indicated by the shading. \Vhile various liquids may be used in the explosion chainber, I prefeiwto employ distilled water or in case the switch is used where the tempera-- ture falls below freezing, I may employ a. mixture of water and glycerine.

The contact mechanism of the switch con1- prises primary and secondary contact members. The primary contact lever 30 is pivoted at 31 and supports a contact brush 32 adapted to cooperate with a stationary contact 13. The secondary contact lever 83 is pivoted at 34 and is connected to the operating rod 38 of the secondary contact 38 through a link 35 and pins 36 and 37. The

in the insulating material of which contact levers and 33 are geared together and are operated by means of the insulat-, ing rod 21.. The operating rod 38 enters the explosion chamber through a stufiing be provided in theaperture 10.

rovision is made for making the final break in the circuit at the movable electrode 38 by use of a sliding contact l5 which is in electrical connection with the stationary contacb 16. l he movement or" this sliding contact 415 to follow the movable electrode 38 is caused by the pressure of the spring 16 which is compressed when the contacts close. The distance which the slid- ,ing contact may move in the upward direction is limited by its head striking against the under surface of the stationary contact 16. A cap 17 is provided to form a seat for the spring 46 and to make it unnecessary to seal the bearing of the sliding contact 15. Qpening 51 is provided in the bottom of the stationary contact 16 for per-. mitting free movement of the sliding coutaet 45.

' An hydraulic dash pot is attached to the chamber cover 11, the piston (31 of which is connected to the secondary contact lever by the link 62. An aperture in the dash pot body is designed to permit fl-e movement oi the piston 61 during the first part of its downward stroke. dis the piston (51 passes below the aperture 55 near the end of the stroke, the dash pot serves a cushion and the contact lever is brought to rest without shock.

Low resistance connection is maintained between the chamber cover 11 and the contact member 30 and lever by the use of flexible leads 65.

Where it is desired to use an explosion chamber adapted to withstand high internal pressure. I can )rovide reinlbrcin means 1 1 L O for the insulated explosion chamber. @no such means is shown in 2 wherein 52 represents an inner insulating condensing casing and 53 an outer shell formed of insulation and reinforced by interlocked annular metallic members 54.

Fig. 3 I have shown another arrangement by which the explosion chamber may be made to withstand high internal pressure. in this term of my invention the metal casing 1 1/1 is a modified *l'orm ol. the casing shown in Fig. 2 and is adapted to receive a removable condensing liningill?) which is a modified .ioriu of that shown in The explosion 'chambcr casing is supported from the tank 10 by an insulator 111 and is held, by a clamping member 150, in a position permitting removal of the explosion chamber. An example of such a fastening means is shown in the patent to Bali, 915,671. Jan. 4-. 1910. The primary contact plat 113 is in electrical contact with the explosion chamber casing 11 1-. The ex- '01" the piston (ll. and the hearth the piston is compiplosion chamber casing is provided with a metallic cover 14-1 to which the hollow lead 24: is fastened. A lead 22) is connected to the contact mechanism support 1412 which is supported from the cover 1 11 by the insulater 1 13 and the insulating bushing 1 1 1. Gas tight connections are provided between the insulating bushing 14- 1 and the (3X]')l0-' sion chamber 115. The stuiling box 1 18 is provided "for the purpose of preventing the escape of gas through the opening provided for the movable contact 38.

In operating under load from the closed position of the switches shown in Figs. 1 and 3, the operating rod is raised by operating means external to the switch. lhe

operating means not shown but may be of any well known construction such. for example as that shown in patent to Hewlett and Button 973,657, bet. 2:), 1910. Movement of the primary brush 32 away from its contact will cause all the current to flow through the auxiliary electrode 38. The insulating liquid 11 will extinguish any are which may tend to 101111 between the brush 32 and its cooperating contact and introduce a high resistance to the passage of current between brush and contact.

After the separation of the primary contacts the electrodes and '3 are separated beneath the surface o l liquid 26. ifhis results in the ocrhiation o1 he liquid which grea s the pressure This presctrode B5 sure assists in through the openin rapid separation or incipient are w separation of these c tinguished and tn tion of water in many respects H1111 to liicholson The hot vapo s sides of the r chamber 15' will ind liquid so formed will flow to ie sumo. thus being available 'l'or i'urther on ":nion ml the switch. I A 1:

The dash po 0 is i=.'orid :d u in an opent (3 ing designed o lf'dj zuorcnn-iu ssociztlcd sccoiuh ary contact lever Ill; during the lirst part of the opening niorcincnt oi the switch. I the piston {51. passes inc opening 35 in l\. downward movement. hour-yer, lhc oil lll" rd and l ol'wll 1121;) in Shchollom pm'init out through a small o of the dash pot thus sci piston and bring 1 3H lo -1l without shock. in H rziliim oi the switch the opcuii us to pcrmit rapid acceleration of h swondar -i (HIP tact 38 during the latter l'dli'b ii its closing movement, tlie shock incident to closure of the switch being absorbed by the spring 46 which supports the movable contact 45.

In closing the switch the operations-are reversed. The operating rod is raised to cause moven ent to close botli the primary brush 32 andthe movable electrode 38. In so doing the movable electrode 38 contacts with the sliding contact i5 and establishes the circuit before the primary brush makes contact. Between the time that the movable electrode38 has made contact with the sliding contact and the instant of final clos-' ing at the primary contact brush 32, both the movable electrode 38 and the sliding contact 45 move downwardly, contact between the two being maintained by the spring l6.

Switches of the class .described may be used for a large variety of conditions of service and my invention in its broader aspects is not limited to the particular constructions shown herein. lVhile I have shown the contact levers 30 and 33 as connected together by means of inter-meshing gears, it is apparent that other suitable ployed for securing the desired mechanical movenumt. Other changes apparent to those skilled in the art may be made without departing from the scope of my invention.

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

1. In a switch, a sealed explosion chamber comprising a reservoir in its lower portion and a. condensing chamber in its upper portion.

A switch of the type whereina circuit broken by the separation of contacts in proximity to a liquid which is vaporized but not permanently afiectedthereby, rlmracterizml by the fact that means are pro- \ided for condensing the vapor of said liquid.

3'. A switch of the type wherein a circuit is broken 'by the separation of contacts beneath the surface of a liquid which is vaporized but not permai'wntly affected thereby, characterized by the fact that means are provided 'l'or condensing the vapor of said liquid.

-'l-. A switch of the type wherein a circuit is broken by the separation of contacts in a reservoir containing a liquid which is vaporized but not permanently affected thereby, characterized by the fact that means are provided for the condensation of the vapor of said liquid and for the return of the condensed liquid to said reservoir.

In a switch havin an explosion chamber formed with a metallic reservoir in its lower portion, an electrode in said reservoir and electrically connected thereto, a metallic cover for said explosion chamber, means connectingsaid cover and reservoir a-nd.serV-..

11103115 ll'ltly be 6111- ing to insulate them from one another, an

said chamber.

7. The combination of a sealed container, contacts separable within said container but not completely withdrawable there-from, said contacts being separable in a liquid which is vaporized but not permanently affected by the breaking of a circuit by said contacts, a tank surrounding said container, said tank being adapted to contain an insulating liquid within which said container is immersed.

8. The combination of a sealed container, secondary electrodes having contact surfaces separable in said container to break a circuit whereby an are formed by the separation of said contacts creates pressure Within said container, said surfaces remaining at all times within said container, a tank enclosing said container, said tank being adapted to hold a liquid container is immersed, and primary electrodes for carrying the main load current separable in said liquid.

9. A switch comprising a sealed chamber containing a liquid, secondary contact members separable within said liquid, said liquid being vaporized but not permanently affected by the breaking of a circuit by said contact members, a tank enclosing said container, said tank being'adapted to hold a liquid within'which said container is immersed, and primary contact members mounted outside said chamber and separable within said tank.

10. A switch having a scaled explosion chamber adapted to contain an arc extinwithin which said guishing fluid, electrodes separable within said chamber to break a circuit whereby an are formed by the separation of said electrodes creates pressure within said chamber, and a terminal connected to one of said electrodesthrough the wall of said chamber, said terminal being formed with a passage for the supply of fluid to said chan'iber.

11. A switch comprising a sealed chamber containing water, primary contact members for carrying the main load current separable without said chamber, and secondary contacts within said chamber for breaking the circuit whereby an are formed at said secondary contacts Vaporizes said water and creates pressure to extinguish said are and to accelerate the separation of said contacts.

12. A switch comprising a sealed chamber immersed in a cooling and lnsulatmg ;1 an arc ,i'ic separable W a circuit 7 will. vanerize suppress if r I V 1 J. H'JizCPh' o l. hlllll. chamber acung c n vapor produced and return the a Sealed chamber 7. 1;: a reser foir ill t r n m ()l, cni aciaplci lo LODLdhi an a c c 1351 liquid, contac 'v separable n niber to break .cc formed will i 1 wall to form a liquid, means for operating one of said con cts extending i'hrough a Wall ol said L1l1l) /L whereby upon 'lhe se 'iararrion of said contacts, in. pors produced by i'hc inlorrupiion of the circuit will acceicrale the separation of said contacts and be condensed on ibe Walls of said chamber and returned to said reservoir.

15. An electric switch comprising a sea led chamber provided with a corrugaicd Wall and containing water in the lower portion thereof, contacts arranged in the lower poriion of said chamber whereby any. are formed upon the Separation of said contacts be drawn in said liquid, means for ing' one of said coniacls cx'lencling wrench a Wall of said chainl whercby upon lhe inierrupiion ol' the circuit by lhe ,irazion of said contacts the vapor presproducod in said sealed chamber will 'nguishing the arc and acceleraeparationof said contacts, said 3 condensed by the cooling acsaid corrugated wall and returned 1e lower portion oi :he chamber.

an witness whe eof have hereunto set an; 'icl tins eleventh day November ifigf ...'JAl,.J-v

1 r F e v JAJJULLLLL Dr.

All; rm, 1

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