US3852544A

US3852544A - Fluid operated electrical contactor with contact coolant means

Info

Publication number: US3852544A
Application number: US00398021A
Authority: US
Inventors: K Grunert; C Paton; J Sentak
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1973-09-17
Filing date: 1973-09-17
Publication date: 1974-12-03
Anticipated expiration: 1991-12-03
Also published as: DE7430529U; JPS5055151U; CA1003468A; CH589929A5; DE2443384A1

Abstract

A contactor characterized by fluid drive means within an insulating housing containing a plurality of corresponding pairs of stationary contacts and movable contacts movable between open and closed positions with respect to each other; at least two pneumatic or hydraulic cylinder motor means for moving the movable contacts between said positions, a remotely controlled actuator motor for directing fluid into corresponding sides of the cylinder motor means simultaneously, gas coolant means for directing currents of coolant gas onto each set of contacts in a direction aligned with the path of travel of the moving contacts, the gas cooling means comprising gas conduits leading to the top of the housing in which the gas inlet nozzles are provided for directing the coolant gas to each of said contacts when the contacts are in the closed position, and safety latch means for holding the movable contacts in the open or closed positions and preferably in the open position.

Description

atent' i 1 United States Grunert et a1.

[ 1 FLUID OPERATED ELECTRICAL CONTACTOR WITH CONTACT COOLANT MEANS [75] Inventors: Kurt A. Grunert, Beaver; Charles R.

Paton; John A. Sentak, both of Brighton, all of Pa.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Sept. 17, 1973 [21] Appl. No.: 398,021

[52] US. Cl 200/82 R, 335/167, 200/243,

[51] Int. Cl. H0lh 35/38 [58] Field of Search 137/59615, 596.18;

335/167; 200/82 R, 82 B, 16 A, 166 K, 169 R, 243, 289

[56] References Cited UNITED STATES PATENTS 2,305,591 12/1942 Sonneborn ZOO/82 R 2,920,170 1/1960 Caswell 200/82 B 3,088,013 4/1963 Watson ..'200/166 K 3,110,792 11/1963 Gauthier 200/169 R 3,457,377 7/1969 Olson 200/169 R 3,602,850 8/1971 Grunert 335/133 3,649,789 3/1972 Stoll 200/82 R 3,745,492 7/1973 Grunert 335/167 FOREIGN PATENTS OR APPLICATIONS 1,152,148 2/1958 France 200/166 K Primary Examiner-Robert K. Schaefer Assistant ExaminerGerald P. T'olin Attorney, Agent, or FirmL. P. Johns 5 7 ABSTRACT coolant gas onto each set of contacts in a direction aligned with the path of travel of the moving contacts, the gas cooling means comprising gas conduits leading to the top of the housing in which the gas inlet nozzles are provided for directing the coolant gas to each of said contacts when the contacts are in the closed posi- .tion, and safety latch means for holding the movable contacts in the open or closed positions and preferably in the open position.

5 Claims, 4 Drawing Figures SHEET 10F 3 FIG. I.

PATENIELUEB I I 3,852,544

sum 20F 3 FLUID OPERATED ELECTRICAL CONTACTOR WITH CONTACT COOLANTMEANS CROSS REFERENCE TO RELATED APPLICATIONS This invention is related to the inventions disclosed in the applications of Kurt A. Grunert, Ser. No. 319,823, filed Dec. 29, 1972, Ser. No. 294,135, filed Oct. 2, 1972, and Ser. No. 199,473, filed Nov. 17, 1971.

BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to an electrical contactor having reversible fluid drive means for moving the movable contacts between open and closed positions.

2. Description of the Prior Art Electric contactors of the type shown in Pat. No. 3,602,850, issued Aug. 31, 1971, to Kurt A. Grunert, are well known in the art. Among other things they comprise an insulating support and a bridge contact structure supported within the support by which movable contacts are moved between open and closed positions with respect to stationary contacts. The contactor also includes an electromagnetic means for moving the bridge contact structure'between those positions. In some electrical control systems, it is desirable to modify the manner of movement of the bridge contact structure from strictly opening and closing the circuitto contact by the application of the necessary force to a movement where variable velocity control is available.

Associated with the foregoing-is the ability to increase the electrical current capability or rating of the particular contactor involved by a. substantial amount, such as from 250 amperes to 1,000 amperes, by increasing :the pressure between the contacts in the closed position and by providing contact coolant means. Where the contacts are open and closed by fluid drive means, a single cylinder is satisfactory for many applications. However, to increase the cylinder sizej instead of increasing the number of cylinders, such as two cylinders instead of one, does not necessarily double the amount of contact force which is desirable for reducing the generation of heat between the contacts in the closed position. Moreover, increasing the size of cylinder results in some instability due to mechanical binding of the piston in the cylinder of larger diameter. i A

SUMMARY OF THE INVENTION In accordance with this invention, it has been found that the foregoing problem may be overcome by providing a circuitinterrupter structure comprising an electrically insulating housing, a plurality of sets of contacts within thehousing and comprising stationary contacts and movable contacts movable between open and closed positions with the stationary contacts, a reversible fluid drive means comprising at least two fluid cylinders and pistons, the movable contacts being movable on a movable contact carrier, the pistons having piston shafts beingoperatively connected to the movable contacts for unison movement thereof, gas coolant means in the housing for directing currents of coolant gasonto each set of contacts, the gas coolantmeans comprising a gas conduit operatively connected to a valve which valve is part of the fluid drive means for remotely controlling the direction of fluid into one or the other side of the fluid cylinder, and latch means comprising a movablelatch member movable to alatch position to retain the contact carrier structure in the'open position.

The advantage of the device in this inventionis that it provides for more stabilized electrical switching control including the variable velocity control by doubling the amount of contact forceto reduce the amount of contact heating, avoids mechanical binding which would otherwise occur with a single piston in a cylinder of larger diameter where one air motor is used, and where the reversible fluid drive means is pneumatic rather than hydraulic, air can be used for cooling the contact in the closed position, thereby increasing the initial rating of a particular circuit interrupter.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a three-pole contactor constructed in accordance with the principles of this invention;

FIG. 2is a vertical sectional view taken along the line II--II of FIG. 1; v

FIG. 3 is a vertical sectional view taken along the line III-III of FIG. 2; and FIG. 4 is an elevational view taken along the line lV-IV of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT a contactor structure 8 supported on the housing structure. The housing structure 7 comprises a base9, a molded insulating intermediate housing portion 10 suitably secured to the base,.and a molded insulating cover 11 suitably secured to the intermediate housing part.

Contactor structure 8 comprises reversible fluid drive means for moving the movable contacts of the contactor between open and closed positions. More particularly, the reversible fluid drive means comprises at least two and preferably a pair of cylindrical motors including a pair of cylinders 13, 14 (FIG. 3), similar pistons 15 (only one of which isshown in FIG. 2), upper and lower closures l7 and 19 and piston shafts 20 and 21.Guide pins 22 extend from the base 9, and separate coil kickout springs 23are supported; on each of the guide pins. The springs 23 are strong enough to override the frictional forces of the cylinders in case of air failure so as to make the system failsafe. A movable contact carrier 25 is provided to cooperate with the reversible fluid drive means in a manner to be hereinafter described. The contact carrier 25 comprises a connecting rod 27 that re sts on ledges 29 and passes through a central opening portion of the carrier Opening 31 is provided .at'opposite ends of the lower portion of the contact carrier andcooperate with the vertical guide pin 21 for guiding vertical movement of the contact carrier 25. The undersurface of the carrier rests upon the upper end of the spring 23, whereby the contacts are biased in the open position when the reversible fluid drive means is not operating. However, use of the spring is optional or may be used for biasing the contacts in the fluid position, such as where the spring 23 is tensile instead of a compression spring.

The contactor is a three-pole contactor with three bridging contact structures 35 supported on each of line) position with the stationary contacts 41 which are located within the cover or-insulating housing 11'. The movable contacts 39 and the stationary contacts 41 are retained in the closed position by the piston of the fluid drive means without the use of mechanical latches. Each stationarycontact 41 is mounted on a separate stationary contact structure 43 which, in turn, is mounted on the inner end of one of two conductors 45. Each conductor 45 is part of a pole unit which is supported on the intermediate housing 10 by bolts 47. Solderless terminal connectors 49 are secured to the outer ends of the conductors 45 to enableconnection of each pole unit toan electric circuit; Asjshown in FIG. 2, the lower end'ofthe contact carrier 25 is secured to the'upper end of the shaft 20. For that purpose, the contact carrier includesa pair of connecting rods 27 and 28, the latter of which extends at

conduits

59 and 61 into opposite end portions of the

cylinders

13 and 14.

The valve 55 may be one of the direct operating type that is disclosed in US. Pat. No'. 3,251,378. Such valves are available for operation either by single solenoid with spring return or by two solenoids. A diagrammatic view of a valve having two solenoids is shown in 'FIG. 3 and comprises a valve chamber 71. As shown, the

conduits

59 and 61 communicate with the chamber 71 and the conduit 57, leading from the source of fluid, also communicates with the chamber. A pair of

solenoids

73 and 75 are located at opposite ends of the chamber 71 for moving the valve member 69 to direct fluid to either side of the piston 15. In the position shown the valve member 69 is located to direct fluid from the conduit 57 to the conduit 61 and into the cylinder 13 on the lower side of the piston 15. Fluid on the upper side of, the piston 15 is exhausted through the conduit 59, the valve chamber 71, and a port 77. When the solenoid 75 is actuated, the valve member 69 is moved to the right whereby the fluid flow is reversed with the fluid from the lower side of the cylinder 13 being exhausted through a port 79. Both ports 77 and 79 lead to fluid supply reservoir (not shown).

The speed of opening and closing of the contacts is controlled'separately by a pair of speed control screws 81 and 83 which are seated in the body of the valve 55. The inner end portions of the screws 81 and 83 extend into the exhaust ports 77 and 79, respectively, by distances dependent upon the speed conditions required. However, the screws 8 l-and 83 maybe disposed in the conduits 5.9 and 61. As shown in FIG. 3, the screw 81 extends a lesser distance across the port77 than the right angles to. the former. The opposite end portions of both rods 27 and 28 are secured to opposite sides of the contact-carrier in the manner similar to that shown for'the connecting rod 27. The connecting rods 27 and 28 have aligned openings for receiving the upper end portion of the shaft 20 and both openings are preferably threaded for engagement with said end portion. In addition,.a lock washer 5l and a lock nut 53 are secured against the underside of the connecting rod 27. Accordingly, when the shaft 20 moves up the movable contacts 39 are moved to the open position. As shown in FIG. 2, when the shaft 20 moves down, the movable contacts are brought into closed positions with the stationary'contacts 41. Q

The reversible fluid drive means including the

cylinders

13,14 are actuated by actuator means comprising a valve 55(FlG. 3) for directing fluid into the cylinders on one or the other side of. the pistons 15. For that purpose, the valve 55 is connected by a conduit 57to a source of fluid, suchas pressurized gas or liquid, de-

pending upon whether'th'e fluid motor comprising the cylinders13, 14. is operated pneumatically or'hydraulically. Supply conduits 59 and'6l extend in pairs from the valve 55 to opposite ends of the cylinders 13 and;

14. The valve 55 may be manually operated, or is preferably operated by remote control in a conventional manner for which reason it is provided with a solenoid operated valve member for whichlead wires 63 andv65 are providedto transmit an electrical impulse to the so lenoid in order to reverse the positionofthe valve and thereby direct-fluid through one or the other of the lead screw 83 extends across the-port. 79.'Thus, the fluid flow from the lower portion of the cylinder 13 is slower than it is from the upper portion, whereby upon closing of the contacts. 39-and '41 there is reduced contact bounce and reduced impact. The screws 81 and 83 may be set for varying positions within the ports 77 and 79 in order to vary the speed of opening and closing of the contacts within therange of from about 0.1 to about l0 feet per second. In addition to reducing contact bounce and impart it. is necessary under some-conditions to regulate the closingspeed for timing reasons. Moreover,.the opening speed may be adjusted for regulating the arcing intensity. 1

Gas coolant means areprovided in order to direct a blast of a' coolant gas, such as air, into the area of the stationary and movable contacts. in order toa-cool the contacts and associated current bearing components. The blast of coolant gas is sustainedat least duringthe time the contacts are opened if necessary todissipate any heat generated while thecontacts are closed. Thus, the'electrical current carrying rating of the contactor is increased significantly, such as twofold, depending upon the flow rate 'and temperature of the coolant gas.

For the'contacts of each pole of the contac tor, thega's coolant means comprises a pair of, inlets or nozzles 85. As shown in FIG. 2, the nozzles 85 are disposed in a top wall'87'of the insulating housing cover 11. Each nozzle 85 is so disposed that it directs a continuous currentof air onto'the upper side oftheassemblyof the contacts.

39 and 41., The coolant'gas mayflow continuouslyor onlyduring the occasions when the contacts are, in the closed position. Suffice it to say, the coolant gasis directed from the nozzles .into the contact area and preferably in alignment with or substantially parallel to the direction of travel of the movable Contacts 39. However, the nozzles 85 may be disposed at another location in the insulating housing cover 11 so as to be directed at angles to the direction of travel of the contacts 39, but not perpendicular or normal to that direction. If the gas were directed perpendicular or normal to the direction of travel of the contacts 39, there would be the undesirable tendency of the arc to be blown back toward the contacts or contact support with resulting damage thereto. The nozzles 85 communicate with a plurality of interconnecting

channels

89, 91 and 93 extending between the several nozzles or inlets 85 in a cover manifold 95. The cover manifold 95 is attached to the upper surface of the cover 11 in a suitable manner, such as screws 97, which cover manifold extends over the several nozzles 85 and

channels

89, 91 and 93. The cover manifold 85 includes a gas conduit 99 that leads to the valve 55 that transmits coolant gas to the conduit 99 when the

contacts

39 and 41 are closed. The cover 11 and the cover manifold 95 are composed of an electrical insulating material, such as polyester or phenolic resins.

As shown in FIG. 1 a latch member 101 is employed for additional safety and is attached (FIG. 4) to one side of the contactor. The latch member 101 is a mechanical device for use by another person such as an electrician or-a maintenance man who is required to perform some duties when the contactor is in the open position as shown in FIG. 4. Employment of thelatch member 101 prevents inadvertent actuation of the con tactor by a person who may be unaware of a second person working on the line. The latch member 101 comprises a mounting bracket 103 and a latch 105. The mounting bracket 103 includes a pair of upright supports 107 and 109. As shown in FIG. 1, the latch 105 is a U-shaped member including spaced legs 111 and 113. The latch 105 is maintained in a retracted or unlatched position (FIG. 4) by coil spring 115. The legs 111 and --113 extend through and are-slidably disposed in spaced pairs of aligned apertures in the upright supports 107 and 109. Similar retaining pins 117 are provided atthe left end of each leg to prevent the latch 105 from being completely retracted from the mounting bracket 103. I

In operation, the latch 105 is used when the contactor 5 is in the open circuit condition by advancing the latch to the latch position as shown in broken line in FIG. 4, whereby the legs 111 and 113 are disposed under the movable contactjcarrier 25. To prevent the springs 115 from retractingfrom the latch position to the unlatched position, one or both of the legs 111 and 113 are provided with a'hole 119, which hole is shown in broken-line position 119a when the latch 105 is in the advanced or unlatched position between the upright supports 107 and 109 as shown in FIG. 4. In that position the shackle of a padlock may be inserted in the opening 119a to prevent the traction of the latch from the latched position by anyone other than an individual having a key to remove the padlock.

Accordingly, the device of the present invention provides reversible fluid drive means comprising at least two fluid motors for actuating the movable contact carrier of a contactor between open and closed positions. In addition, the device provides for a coolant means directed preferably onto the movable contacts to enable operation of the contactor at a lower temperature and therefore at a higher rating. Finally, latching means for safety purposes is provided to prevent inadvertent closing of the contact.

What is claimed is:

1. A circuit interrupter structure comprising an electrically insulating housing, a plurality of sets of contacts within the housing and comprising stationary contacts and movable contacts movable between open and closed positions, an elongated contact carrier along which the sets of movable contacts are disposed in spaced relationship, reversible fluid drive means comprising at least two fluid cylinder and piston structures and having piston shafts connected to and at spaced positions along the elongated contact carrier, the fluid drive means comprising a remotely controlled valve mechanism directing fluid into one or the other side of the fluid cylinders uniformly so that the assembly of the elongated contact carrier and the sets of movable contacts is movable in a stable, non-binding manner.

2. The circuit interrupter structure of claim '1 in which the fluid drive means comprise two fluid cylinder and piston structures.

3. The circuit interrupter structure of claim 1 in which the remotely controlled valve mechanism comprises means for adjusting the flow rate of the fluid into and out of said valve mechanism.

4. The circuit interrupter structure of claim 1 in which gas coolant means connected to said valve mechanism for directing currents of coolant gas onto each set of contacts in a direction aligned with the path of travel of the movable contacts are provided in the insulating housing, in which the fluid is a gas, and in which the gas coolant means comprises a gas conduit operatively connected to the valve.

5. The circuit interrupter structure of claim 1 in which the gas coolant means operates only when the contacts are closed.

Claims

2. The circuit interrupter structure of claim 1 in which the fluid drive means comprise two fluid cylinder and piston structures.