US2145720A - Switching apparatus - Google Patents

Description

Jan. 31, 1939. 5 v G|EGER|CH 2,145,720

SWITCHING APPARATUS Filed June 25, 1957 Inventor: Bertrand. Gie er'loh,

ttor'ney.

Patented Jan. 31, 1939 UNITED STATES PATENT OFFICE SWITCHING APPARATUS New York Application June 25, 1937, Serial No. 150,390

Claims.

My' invention relates to improvements in. switching apparatus for electric systems and more particularly low voltage network distribution mtems. In such systems which are used princi- 5 pally in metropolitan areas, it' is customary to place the transformers in vaults. Because of property values and building costs, such vaults are much restricted as to size. Also because of the fire hazard, it has become necessary to use a noninflammable insulating liquid in the transformers and appurtenances thereto. Such liquids are relatively costly so the question of compactness is further accentuated. Moreover, for safety in inspection and maintenance, it is desirable to ground the high voltage side of the transformer and the line conductors connected thereto. It must not, however, be possible to do this while the transformer is energized since it is not economically feasible to build the grounding switches with any large circuit rupturing capacity. In the usual arrangement of grounding switches, two sets of insulators have been used,

one set on which the contacts are mounted in the switching chamber and another set giving entrance to the transformer tank from the switching chamber. Sucharrangements are bulky and incompatible with the space limitations for installation not only because of the limited vault size but also the necessity for entrance to and exit from the vault through a comparatively small opening. In accordance with my invention, I

provide an improved switching apparatus which uses only one set of insulators whereby-to attain compactness, economy and reduction in weight 5 because of less equipment, ease of manufacture and necessity for less of the relatively costly non-inflammable insulating liquid. Further, in accordance with my invention, I provide a switching apparatus which is removable from its enclosingstructure on the transformer tank without the necessity'for removing any insulating liquid from the transformer whereby the inspection and maintenance of structure.is greatly simplified. Also, in accordance with my invention, I provide an improved switching apparatus which is not operable to ground the transformer while the latter is energized. These, and other objects of my invention, will appear in more detail hereinafter.

5 My invention will be better understood from the following description when considered in connection with the accompanying sheet of drawings, and its scope will be pointed out in the appended claims.

55 In the accompanying drawing, Fig. 1 illustrates in perspective an embodiment of my invention with parts broken away to show the structural features; Fig. 21s a horizontal sectional view, with parts broken away, of the embodiment of my invention shown in Fig. 1 as applied to a trans- 5 former casing; Fig. 3. is a perspective view of a detail of the embodiment of my invention shown in Fig. 1; Fig. 4 is a detail in section of a locking arrangement for use with switches embodyi my invention; and Fig. 5 is a detail of another 10 of the support. Instead of the wedge and jaw 20 type of contacts, other suitable forms maybe used as, for example, the bayonet and socket co-operating contacts 6' and 9' shown in Fig. 5. The support I may take the form of a hollow box-like or enclosing structure provided with a 25 cover II. This structure is suitably adapted, as shown, to be secured over an opening in the side or top of a transformer casing 12 with the insulators Ill projecting into the casing. Inasmuch as the transformer construction per se 30' forms no part of my invention, I have in Fig. 1 merely illustrated schematically, for clarity in understanding the use of my invention, low voltage windings l3 which supply a network, not shown, and high voltage windings II which are 35 energized from a feeder comprising phase conductors IS. The high voltage windings ll are '-connected to terminals I 8 forming a part of the stationary contacts 9 and closing the ends of the insulators l0.

For actuating the movable contacts simultaneously, they are suitably secured to a crosshead. I! which may be of metal such as steel and which is slidably mounted on guide rods'll. The free ends of the contacts 5 are suitably guided as by 45 bushings 19 set in a guide plate 20 which is suitably secured to the support 1. In order to insure a good current bonding and grounding action when the contacts 6 and 9 are closed, the crosshead ll may be backed up on the contact side by a copper bar 2| from which a suitable grounding lead 22 extends to the plate 2! which is grounded through the transformer casing.

For actuating the crosahead I! to effect engagement and separation of the contacts 5 and guide rods [8.

or more cranks 26 which are pivotally connected 9, I provide suitable means such as an operating shaft 23 which is suitably iournsled in block it, secured to the plate 2!. Plates 25, secured to the blocks 24, may be used tosupport one end of the The shaft 21 is provided with one to the crosshead l'l'through links 2'!- wherebyto reciprocate the crosshead when the shaft is turned. In order to control the angiflar movement of the shaft 23 for the necessary contact engagement and separation, the shaft end of one of the cranks 26, the right hand crank as shown in Fig. 1, may be suitably shaped to engage, in. one position or the other, one of the adiustably positioned stops 28 and 2! which are mounted on a plate 3| suitably secured to the right hand block I. a

v For actuating the operating shaft 23, I provide an extension shaft it which proiects through a fluid tight bushing 32 into thesupporting structure l and has a slotted end 33 for engaging a tongue on the end of the operating shaft. To retain the extension shaft 3! in engagement with the operating shaft, a threaded locking pin it may be screwed into the supporting structure to engage a recess in the extension shaft. Near the outer end of the extension shaft, there is secured thereto an operating lever 35, the end of which may be provided with an opening it to which a flexible cord such as a rope may be secured so that the switch can be remotely operated from the outside of the usual vault which houses the transformer to ground the transformer without the necessity of entering the vault and possible danger attendant thereon in the event of unusual or unknown conditions prevailing at the time it is .desired to operate the switch. The switch may be locked in the open position, as shown by inserting a padlock through openings in oowhich is adapted to engage a recess in the support 1. When-thus engaged, as padlock through operating members 31 and 38 mounted on the lever 35. As shown more clearly in Fig. 4, the

locking member 31 is slidably positioned on the lever 35 and'is provided with a projecting end 39 the registering openings in the members 31 and 38 effectively prevents any actuation of the shaft 23.

In order to prevent operation of the switch to the grounding position while the transformer is energized, means are provided for locking the shaft 23 against turning while the switch is open and the transformer is energized. As shown, this means comprises an electromagnet lli which may be bracketed on one of the blocks 24 and whose armature ll is arranged to actuate a locking member such as a pin 42. This pin is.guided by a plate 43 so as to enter an opening in a collar H on the shaft 23 when the switch is open. The movement of the armature to the unattracted position may be by gravity or by spring action and is limited by a plate 45, shown in Fig. 3. Also, as illustrated, the electromagnet'fl has its winding connected to be energized by the voltage to ground of one leg or winding ii of the low voltage side of the transformer, a lead 45 being brought through an insulator 41 mounted on the support I to a lead 48 connected to one terminal of-the electromagnet winding. The other terminal of the winding may be grounded on the frame mechanism at 45, as vshown. With this arranager'nent, it will be obvious that while the transformer is energized, either fromthe high voltage side or the low voltage side, the pin 42, actuated by the electromagnet ll, will engage the recess in. the

collar It whereby to prevent any operation of the switch. When the electromagnet' ll is deenergized, the switch may be closed to ground the transformer byflrst moving the member 31 so as to disengage the portion 3! thereof from the support I whereupon an. upward pull; as viewed in Fig. I. on the lever 35 moves the contact tips 8 to engage the contacts 8. 4

with apparatus embodying my invention, it will be apparent that the switching mechanism may.

be readily removed without the necessity of drawing of! insulating fluid from the transformer. To remove the mechanism, the insulating fluid, if any, may be drained from the supporting structure T. The-cover plate It is removed, and the lead 48 disconnected. The retaining pin 34 is then backed off sufliciently to permit the extension shaft 35 to be withdrawn from engagement with the tongue on the operating shaft 28. Then merely by unscrewing the bolts which secure the base plate 20 to the supporting structure I, the switch-operating mechanism, including the movable contacts 6, maybe withdrawn. when this is done, the condition of the contacts 9 may also be examined. The accessibility and compactness of the arrangement is, therefore, obvious. when the switch enclosing structure I is mounted on the side of the transformer casing, this structure may be fllled with insulating fluid. when the switch is mounted on the cover of the transformer casing, the insulators ill extend into the transformer insulating liquid above the level of the contacts, but the enclosing structure I itself does not necessarily have to be filled with insulating liquid.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arranagements shown but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

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

1. In an electric switch adapted-for use with a transformer having a casing provided with an opening, a support provided with an opening and adapted to be secured across the opening in the transformer casing, a movable contact, actuating means for moving said contactthrough the opening in said support. said movable contact and said actuating means being mounted on the support on the side thereof away from the transformer casing, a hollow insulator mounted over the opening in said support on the side thereof toward the transformer casing and extending into the opening in the transformer casing, and a contact mounted within said hollow insulator in a position to be engaged by said movable contact upon movement thereof in one direction.

2'. In combination with a transformer casing and extending into the transformer casing, a

contact within each insulator conductively connected to the insulator terminal, a co-operatlng movable contact for each of said fixed contacts mounted within said structure for movement to engage the fixed contact in the corresponding in- I means within said structure for actuaiispao 5 insulators respectively mounted over the openings in the support on the side thereof toward the transformer casing and extending into the casing through the opening therein, a fixed contact mounted within each insulator at the end thereof extending into the transformer casing, a co-operating movable contact for each of said nxed contacts mounted on the side or said support away from the transformer casing for rectilinear movement relatively to "the corresponding fixed contact, and means for actuating said movable contacts mounted on saidsupport.

4. In combination with an electrical apparatus casing provided with an opening; a switch enclosing structure having one side secured across the opening in saidcasing and provided with an opening, said casing and structure being at ground potential, a hollow insulator mounted on the outside of said structure over the opening on the side 01' the structure secured -to said casing I so as toproject into the casing, a terminal closing the end of said insulator and extending into said casing, a contact within said insulator conductively connected to the insulator terminal, a; cooperating movable contact for said fixed contact mountedwithin said struct ure for movement to engage the fixed contact in the insulator,

means withinsaid structure for actuating said movable contact, and means including a removable cover on said structure Ior providing access to said contacts and said actuating means without removing the structure from the casing.

5. In an electric switch'adapted for use with an electrical apparatus having a casing provided with anopening, a switch enclosing structure minal closing the end 01' each insulator and ex- "tending into said casing, a contact withinseach insulator conductively connected to the terminal,- a cooperating movable contact for each of said fixed contacts mounted within said structure for -movement to engage the fixed contact of the corresponding insulator, means within said structure for actuating said movablecontactsyand means for obtaining access to said contacts and actuating mechanism while said structure is in position on said casing without entry into the casing.

BERTRAND V. GIEGERICH.

having one side adapted to be secured across the

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