US2473861A - Metal-clad switchgear - Google Patents

Description

June 21, 1949. CHUBBUCK 2,473,861

METAL-GLAD SWITCHGEAR Filed June 15, 1946 myz.

9 La l WITNESSES: INVENTOR Leohard 5. 671a bbuc/r.

ATTOR Y ZXZM WWW L Patented June 21, 1949 METAL-GLAD SWITCHGEAR Leonard B. Chubbuck, Hamilton, Ontario, Canada, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 15, 1946, Serial No. 676,895

3 Claims.

My invention relates, generally, to metal-clad switchgear, and, more particularly, to devices for lifting the circuit breakers into the operating position in the switchgear cells.

In metal-clad switchgear of the vertical lift type, it is customary to raise the circuit breakers into a position where the breaker bushings make contact with connections to the bus bars which are located above the circuit breakers. This work has previously been done by hand or motor operated mechanical devices which are somewhat complicated and expensive.

An object of my invention, generally stated, is to provide a lifting device for metal-clad switchgear which shall be simple and efficient in operation and which may be economically manufactured and installed.

A more specific object of my invention is to provide a fluid-pressure operated lifting device for metal-clad switchgear.

Another object of my invention is to provide for individually controlling the operation of a plurality of fluid-pressure operated lifting devices for metal-clad switchgear.

Other objects of my invention will be explained fully hereinafter or will be apparent to those skilled in the art.

In accordance with one embodiment of my invention, a fluid-pressure operated device is provided in each one of a plurality of switchgear cells for lifting the circuit breakers to their operating position. The operation of the devices is so controlled that each breaker may be raised and lowered independently of the other breakers. All of the devices are supplied with fluid by a single pressure pump which is connected to the devices through control valves.

For a better understanding of the nature and objects of my invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawing, in which:

Figure l is a view, in front elevation, of metalclad switchgear embodying the principal features of my invention, and

Fig. 2 is a view, in side elevation, of the structure shown in Fig. 1.

Referring to the drawing, particularly to Fig. 1, the structure shown therein comprises two metalclad switch-gear cells of the usual type having a circuit breaker unit ll disposed in each cell. The circuit breakers are of the vertical lift type, each breaker having contact members 12 disposed to engage cooperating contact members 13 which are connected to bus bars located in a 2 compartment I4 above the circuit breakers. It will be understood that additional cells may be provided.

In accordance with the usual practice, a breaker unit may be wheeled into a cell on a truck I5. The breaker is then raised vertically to its operating position in which the contact members 12 and I3 are fully engaged. Since the breakers are relatively heavy, it is necessary to provide a lifting device of some type to raise and lower the breakers in the cells It]. The lifting devices previously utilized have been of a mechanical type, such as lifting screws which are either hand or motor driven through gears and chains.

In order to simplify the elevating mechanism for the circuit breaker units, I have devised a fluid-pressure operated device in which the operating medium may be either a liquid, such as oil, or a gas, such as compressed air. As shown, in the floor of each cell is located a hydraulic lift I6 capable of raising or lowering the breaker H through the necessary travel.

A fluid reservoir H, a suitable pump and check valve l8, a motor IQ for driving the pump, and a combined excess pressure release valve and electrically operated discharge valve 2i are located at one end of the structure. The pump 18 and the valve 2| are connected to a header pipe 22 which extends along the rear of the cell structure. Standard valves 23 control the flow of fluid between the header pipe 22 and the individual lifts IS. A pipe 24 connects each valve 23 to the bottom of its lift. A hand wheel 25 is located at the front of each cell and is connected to the valve 23 at the rear of the cell by a rod 26.

A standard double-make push-button switch 21 is located on the face of each cell Ill. The top or Raise button connects the motor [9 across a power source, causing the pump l8 to build up pressure in the header pipe 22. The bottom or Lower button connects the discharge valve 2| across the power source, thereby venting the header pipe 22 into the reservoir II.

To raise any breaker, its respective valve 23 is first opened by turning the proper'handwheel 25. The Raise push button for the breaker is held closed until the breaker is raised to its operating position. The finger is then removed from the push button and supporting pins 28 put in place underneath shoulders 29 on the breaker tank to hold the breaker in its elevated position.

The Lower button is then pressed to allow the lift plunger to drop a short distance to release an interlock (not shown) which prevents the breaker from being closed while it is being raised or lowered in the cell. Other standard forms of interlocking may be utilized if desired. The valve 23 is then closed, thereby retaining the lift plunger almost fully elevated. Guide members 3| may be provided on the sides of the breaker tank to keep it located properly in the cell while being raised or lowered.

To lower any breaker, its valve 23 is opened and its Raise button pressed to raise the breaker tank oil the supporting pins 28. The pins 28 are removed and the Lower button held closed until the breaker is lowered onto the truck IS. The valve 23 is then closed.

In case the Raise push button switch is closed after an operation is completed, pressure will be built up in the system but the excess pressure release valve Will open to thereservoir I! to prevent the pressure from becoming dangerous. It will be noted that pressure is applied to the system during only a short time during each operation. If desired, the system may be converted from hydraulic to compressed air by substituting a compressor for the pump I 8.

From the foregoing description, it is apparent that I have provided a lifting device for switchgear which is simple, eificient and safe in operation. Provision is made for individually controlling the operation of any one of a plurality of lifting devices which are connected to the same source of pressure fluid.

Since numerous changes may be made in the above-described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a metal-clad switchgear, in combination, a plurality of cell structures, a circuit breaker for each cell, a fluid-pressure device in each cell for raising the circuit breaker in that cell, a single header pipe for supplying pressure fluid to all of the devices/an individually operable valve for connecting each device to the header pipe, a single discharge valve for releasing the pressure fluid from the header pipe, and individually operable electrical control means associated with each cell for controlling the operation of the discharge Valve.

2. In metal-clad switchgear, in combination, a plurality of cell structures, a circuit breaker for each cell, a fluid-pressure device in each cell for raising the circuit breaker in that cell, a single header pipe for supplying pressure fluid to all of the devices, an individually operable valve for connecting each device to the header pipe, pump means for creating fluid pressure in the header pipe, a single discharge valve for releasing the fluid pressure from the header pipe, and individually operable electric switches associated with each cell for controlling the operation of said pump means and said discharge valve.

3. In metal-clad switchgear, in combination, a plurality of cell structures, a circuit breaker for each cell, a fluid-pressure device in each cell for raising the circuit breaker in that cell, a single header pipe for supplying pressure fluid to all of the devices, an individually operable valve for connecting each device to the header pipe, means for creating fluid pressure in the header pipe, a single discharge valve for releasing the fluid pressure from the header pipe, and individually operable electrical control means associated with each cell for controlling the operation of said means for creating fluid pressure and said discharge valve.

LEONARD B. CHUBBUCK.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,873,787 Rankin Aug. 23, 1932 1,878,999 Ainsworth Sept. 27, 1932 1,889,269 Woodbury Nov. 29, 1932- 1,928,460 Paxton Sept. 26, 1933 1,975,278 Lebel Oct. 2, 1934 2,058,377 Francis Oct. 20, 1936 2,169,481 Sillers et a1. Aug. 15, 1939

Images