US3219848A - Actuator device - Google Patents

Description

Nov. 23, 1965 E. L. LUEHRING 3,219,848

ACTUATOR DEVICE Original FiledFeb. v, 1961 FIG-l INVENTOR. ELMER L. LUEHRING ATTORNEY United States Patent 3,219,848 ACTUATOR DEVICE Elmer L. Luehring, Cleveland Heights, Ohio, assignor to Joslyn Manufacturing and Supply Co., doing business as High Voltage Equipment Company, Chicago, Ill., a corporation of Illinois Original application Feb. 7, 1961, Ser. No. 87,719. Divided and this application Feb. 12, 1962, Ser. No.

2 Claims. (Cl. 307136) This application is a division of my co-pending patent application Serial No. 87,719, filed February 7, 1961, for Actuator Device, and the invention has particular significance in connection with high voltage switches with tandem vacuum interrupter actuation.

High voltage switches have been extensively employed in the past, particularly in connection with outdoor switching stations for isolating sections of transmission lines and associate apparatus. Such high voltage switches are generally air-break switches provided with arcing horns as for interrupting transformer magnetizing currents. In recent years there have also been associate vacuum bottle interrupters to prevent arcing even at the arcing horns.

Present day transmission lines, transformers, capacitors, and the like, involve voltages, and charging and other currents to be interrupted, so large that as many as eight vacuum interrupters have heretofore been arranged mechanically in tandem and, usually, electrically in series, and there are usually mechanical operating rods which operate all the interrupters together.

Compression springs (one for each unit) have been found useful in connection with such mechanism so that, on closing, after the interrupter contacts are closed the rods may undergo a certain amount of overtravel to compress such springs, so that all contacts may close with a more nearly equal contact force.

There have been difficulties associated with high current vacuum contact operation in the past because upon opening, as the contacts at first have zero pressure upon them, there is a high resistance between them causing melting and an electron path extending between the separating contacts due to thermionic emission, and this is not only destructive to the contacts but prevents effective current interruption at a predictable time.

It is an object of the present invention to provide simple and inexpensive means for overcoming the above-mentioned difiiculty.

Another object is to provide an improved mechanically initiated operating linkage for plural circuit interrupters.

A further object is to provide apparatus which will greatly improve the capabilities of the vacuum switch by eliminating the possibility of contact melting and thermionic emission caused by high current during open- Other objects and advantages will become apparent and the invention may be better understood from consideration of the following description taken in connection with the accompanying drawing, in which:

FIG. 1 is a side view primarily in vertical section and showing tandem interrupter operation initiation mechanism incorporating the present invention.

FIG. 2 is a diagrammatic view of a modified arrangement where the tandem interrupter operation initiation mechanism is placed below the interrupters.

In FIGS. 1 and 2 legend numbers are the same as the corresponding FIGS. 4 and 5 of the above mentioned parent application, and although no interrupter unit is shown in the present FIG. 1, it should be understood that a number of like enclosed-against-ambient (e.g. vacuum interrupter) units (15 in FIG. 2) are arranged "ice to be operated in tandem. When an initial signal is sent by some means (not shown) to actuate a normally top or bottom mounted apparatus which may comprise a toggle (not shown herein but one example of which is fully illustrated and described in US. Patent 2,955,181 issued October 4, 1960, and assigned to the assignee of the present invention) this operates a main operator rod 10 (FIG. 1) up or down while it is capable of making contact through its point with a main pushbar 111, so that with downward movement of 10, 110 pushes 111 downward, and, with 10-110 retracted (as shown in FIG. 1) 111 is allowed to raise up (at certain times as hereinafter explained) under the influence of other forces such as opening springs 112 biasing vertical rods 23 and the bar 111 to which they are secured upward with respect to a stationary frame 12.

Push bar 111 has an armature portion 113 cooperating with an electromagnet 114 temporarily magnetized by a solenoid shown only diagrammatically at 115. The solenoid is energized responsive to current through a line L1 assumed in circuit with one of the vacuum contacts and is used to prevent opening of these contacts except at current values smaller than a predetermined value of instantaneous current therethrough.

FIG. 2, in which like parts are like numbered as before, schematically illustrates a preferred embodiment. A bottom mounted mechanical, electrical or hydraulic control mechanism shown in block form at 50 controls a main draw bar 11a rotatable about a fixed pivot 51 to downwardly pull or alternately release an armature portion 52 cooperating with a stationary electromagnetic yoke 53. Armature 52 is mechanically associated with a plurality of insulating material operating rods 23a, 23b, 230, coupled end-for-end as by threaded sockets 54, al though other linkage, such as a cable, might have been used instead of rods and couplings. As shown in FIG. 2 each socket operates a cross bar 24a, one for each unit, and each cross bar is tied at the opposite end to a combination of a compression spring 55 (which operates as a pressure spring to increase contact force in the contact-closed position) and a hydraulic unit 30a, which can take the form of the hydraulic actuator fully described and illustrated in connection with FIG. 3 of the aforesaid parent application, and with or without a top reservoir bellows (not shown in the present application FIG. 2 it being assumed that its reservoir function is performed internally or within a piston-cylinder expansion accommodating bellows 34). Springs 55 may be omitted by depending on atmospheric pressure acting on the outer end of the movable contacts, if desired.

In the arrangement of FIG. 2, each evacuated glass envelope 15 contains stationary contact 16 and movable contact 17, and each cross bar 24a is connected to operate the mobile contact 17 of the respective vacuum interrupter, while leads L1, L2, L3, L4, and L5 complete the electrical connections at each end and between units, with L4 and L5 connected to coils 57 forming the solenoid on the stationary electromagnet 53.

With the arrangement shown in FIG. 2 the compression springs 58 operate, at least one for each unit, as opening springs each interposed between a fixed point (59) and the associate cross bar 24a, and operative to open the associate contacts 17-16 but only with relatively low value of current through the solenoid wound upon the yoke 53.

For closing, the arm 11a moves the armature 52 and thus the rods 23a, etc., directly.

Mechanism according to FIG. 1 or FIG. 2 considerably increases the capabilities of the vacuum switch, actually more than doubling its interrupting capacity, because it does away with zero pressure on contacts for opening until the current is low enough, for example less than 3000 amperes, so that critical contact-melting currents and thermionic emission are readily avoided.

Possibly the solenoid arrangement for delayed opening as illustrated in FIGS. 4 and 5 could not be accomplished before the introduction of a hydraulic system, or an equivalent system operable by air, mechanics or electricity, since the vacuum contacts could not theretofore be opened fast enough because the pull rod and control apparatus had to go from zero velocity through a certain distance of travel without any apparent possibility of anticipation because of lack of steady state conditions.

There is thus provided apparatus of the class described capable of meeting the objects above set forth.

While I have illustrated and described particular embodiments, various modifications may obviously be made without departing from the true spirit and scope of the invention which is intended to be defined by the appended claims taken with all reasonable equivalents.

I claim:

1. In a switch of the type having stationary contacts and movable contacts for controlling a principal electrical circuit,

and having first means for closing the movable contacts upon the stationary contacts,

and having second means for opening the movable contacts with respect to the stationary contacts,

the novel combination of:

an electromagnet having a winding which is directly series connected in the principal circuit which said switch controls,

and an armature which is magnetically associated with said electromagnet and which armature is mechanically associated with said second means so as to prevent opening of said contacts except with values of current through the contacts less than a predetermined value.

2. In combination a high voltage switch having plural electrically series connected and mechanically tandem connected electrical circuit interrupters each having a stationary contact and a movable contact,

linkage means connected to operate the movable contacts substantially in unison,

a magnetic material relay armature,

an electromagnet arranged cooperatively with said armature and having an energizing coil means,

one of said last two claimed things (namely, armature and electromagnet) being connected to move with the linkage means while the other is stationary,

connections making a series electrical circuit through the plural interrupters, when closed, and also through the energizing coil means of the electromagnet,

supervisory means for moving the linkage means and thereby moving the movable contacts of the plural interrupters from open to closed position and meanwhile closing the armature-electromagnet combination,

and spring means biasing the interrupter movable and stationary contacts apart and biasing the armature and electromagnet apart to open the same when the supervisory means is released except when values of current through the contacts and hence through the electromagnet energizing coil means exceed a predetermined maximum value permissible for opening operation so as to retain the interrupters and the armature-electromagnet combination in closed position, whereby to prevent thermionic emission and melting damage to the contacts of the interrupters.

References Cited by the Examiner UNITED STATES PATENTS 4/1930 Gay 307X 10/1958 Beyrard 3171l

Claims (1)

1. 2. IN COMBINATION A HIGH VOLTAGE SWITCH HAVING PLURAL ELECTRICALLY SERIES CONNECTED AND MECHANICALLY TANDEM CONNECTED ELECTRICAL CIRCUIT INTERRUPTS EACH HAVING A STATIONARY CONTACT AND A MOVABLE CONTACT, LINKAGE MEANS CONNECTED TO OPERATE THE MOVABLE CONTACTS SUBSTANTIALLY IN UNISON, A MAGNETIC MATERIAL RELAY ARMATURE, AN ELECTROMAGNET ARRANGED COOPERATIVELY WITH SAID ARMATURE AND HAVING AN ENERGIZING COIL MEANS, ONE OF SAID LAST TWO CLAIMED THINGS (NAMELY, ARMATURE AND ELECTROMAGNET) BEING CONNECTED TO MOVE WITH THE LINKAGE MEANS WHILE THE OTHER IS STATIONARY, CONNECTIONS MAKING A SERIES ELECTRICAL CIRCUIT THROUGH THE PLURAL INTERRUPTERS, WHEN CLOSED, AND ALSO THROUGH THE ENERGIZING COIL MEANS OF THE ELECTROMANET, SUPERVISORY MEANS FOR MOVING THE LINKAGE MEANS AND THEREBY MOVING THE MOVABLE CONTACTS OF THE PLURAL INTERRUPTERS FROM OPEN TO CLOSED POSITION AND MEANWHILE CLOSING THE ARMATURE-ELECTROMAGNET COMBINATION, AND SPRING MEANS BIASING THE INTERRUPTER MOVABLE AND STATIONARY CONTACTS APART AND BIASING THE ARMATURE AND ELECTROMAGNET APART TO OPEN THE SAME WHEN THE SUPERVISORY MEANS IS RELEASED EXCEPT WHEN VALUES OF

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