US 4,663,504 A · Load break switch

Abstract

A single-phase ground enclosed load break switch for distribution voltages has a hermetically sealed cylindrical metal housing of from 2 to 6 inches diameter which contains an insulating gas under pressure. The switch has a movable contact assembly to contact a pair of opposed stationary coaxial conductors within the housing. Movement of the contact assembly along one conductor breaks the connection with the other conductor and simultaneously reduces the sliding contact force on the first conductor. The switch has conductive bands coaxially positioned near the housing around the conductors for low voltage measurements monitoring conductor energization and contact position. A rocking bellows at the fulcrum of a crank actuator provides a compact hermetic seal for the actuator without excessive strain of the bellows. A safety interlock with a visual indicator locks the contact assembly in case of a loss of pressure. Excessive pressure in the switch causes the bellows to be punctured with consequent locking of the contact assembly. The switch is small enough to be mounted directly on a transformer or placed into a cable, without the need for a separate enclosure.

Claims49

Dependent claims

A switch comprising:

(a) a housing;
(b) first and second opposed conductors in the housing;
(c) a contact assembly between the conductors movable between a first closed position in electrical contact with both conductors and a second open position in contact with only the second conductor, the assembly comprising:
(i) a plurality of electrically conducting rods arranged in a cylindrical configuration around the conductors, the rods being in sliding contact with the second conductor and, only when proximate to the closed position, in sliding contact with the first conductor;
and
(ii) biasing means for exerting an inwardly directed force on the rods toward both conductors, the force being at a first level when the contact assembly is in the first closed position and at a second level when the contact assembly is not in contact with the first conductor, the first level being greater than the second level.

3 more elements

A switch mounted in a circuit of from about 1 to about 36 kV and capable of continuously carrying and interrupting at least 100 amperes, the switch comprising:

(a) a grounded conductive cylindrical housing having opposite ends and a side and a diameter of less than about 6 inches (150 mm);
(b) first and second opposed conductors at opposite ends of the housing;
(c) a contact assembly between the conductors movable between a first closed position in electrical contact with both conductors and a second position in contact with only the second conductor, the assembly comprising;
(i) a plurality of electrically conducting rods arranged in a cylindrical configuration around the conductors, the rods being in sliding contact with the second conductor and, only when proximate to the closed position, in sliding contact with the first conductor;
(ii) biasing means for exerting an inwardly directed force on the rods toward both conductors, the force being at a first level when the contact assembly is in the first closed position at a second level when the contact assembly is not in contact with the first conductor, the first level being greater than the second level;
(d) an actuating arm protruding through the housing and movable between first and second positions;
(e) a bellows hermetically sealed to the arm and to the housing, the bellows deflecting in rocking mode when the arm is moved between the first and second position;
(f) means connecting the arm to the contact assembly so that by moving the arm between its first and second position the contact assembly is correspondingly moved between the closed position and the open position;
(g) an insulating gas within the housing;
(h) an insulating liner within and spaced apart from the housing, with an annular space between the liner and the housing, the insulating liner serving as a cylinder for guiding the contact assembly;
(i) sealing means in the annular space between the liner and the housing, the sealing means dividing the housing into first and second sections proximate to the first and second conductors respectively, the first section including the annular space, the first section being larger than the second section so that the first section holds more insulating gas than the second section;
(j) a nozzle on the contact assembly for directing the insulating gas to the conducting rods and the first conductor, wherein the contact assembly is adapted to function as a piston in the insulating liner and pumps the insulating gas through the nozzle onto the first conductor as the contact assembly moves from the closed position to the open position;
and
(k) first and second conductive bands on the insulating liner coaxially positioned between the respective first and second conductors and the grounded housing for measurement of voltages on the respective first and second conductors by capacitive division.

11 more elements

An assembly comprising:

(A) a plurality of switches, each switch comprising:
(a) a housing;
(b) first and second opposed conductors in the housing;
(c) a contact assembly between the conductors movable between a first closed position in electrical contact with both conductors and a second open position in contact with only the second conductor, the assembly comprising:
(i) a plurality of electrically conducting rods arranged in a cylindrical configuration around the conductors, the rods being in sliding contact with the second conductor and, only when proximate to the closed position, in sliding contact with the first conductor;
(ii) biasing means for exerting an inwardly directed force on the rods toward both conductors, the force being at a first level when the contact assembly is in the first closed position at a second level when the contact assembly is not in contact with the first conductor, the first level being greater than the second level;
(B) bracket means for mounting the switches positioned in parallel;
and
(C) actuator means connected to each switch for moving the respective contact assemblies in unison.

6 more elements

A single phase ground enclosed load break switch for use in electrical circuits in the voltage range of from about 1 to about 36 kilovolts which comprises:

(a) a sealed, grounded, cylindrical housing comprised substantially of metal having a diameter in the range of from about 2 to about 6 inches (50-150 mm);
(b) first and second bushing means mounted so as to penetrate said cylindrical metal housing, one of said bushings being mounted proximate one end of said housing and the other being mounted proximate the other end of said housing, each of said bushings having an electrical conductor therethrough;
(c) a contact assembly capable of assuming a first position in which it is in physical and electrical contact with the electrical conductor of each of said bushings and a second position in which it is physically and electrically separated from at least one of said conductors;
(d) means for causing said contact assembly to move from said first position to said second position, thereby causing said contact assembly to be separated from at least one of said conductors thus interrupting current flow through the switch and conversely from said second position to said first position, thereby causing said contact assembly to be in contact with each of said conductors thus providing a path for current flow through the switch;
(e) means for maintaining said contact assembly in alignment with the conductors of the bushings, said means comprising a piston extending from the contact assembly to the cylindrical housing;
and
(f) an insulating gas in said housing maintained at a pressure of up to about 5 atmospheres absolute;
said switch being adapted to be electrically connected between a load and a power source having a voltage in the range of from about 1 to about 36 kilovolts.

5 more elements

A single phase load break switch for use in electrical circuits in the voltage range of from about 1 to about 36 kilovolts which comprises:

(a) a sealed, grounded, cylindrical housing having a diameter in the range of from about 2 to about 6 inches (50-150 mm);
(b) first and second bushing means coaxially penetrating said cylindrical metal housing, one of said bushings being mounted proximate one end of said housing and the other being mounted proximate the other end of said housing, each of said bushings having an electrical conductor therethrough;
(c) a contact assembly capable of assuming a first position in which it is in physical and electrical contact with the electrical conductor of each of said bushings and a second position in which it is physically and electrically separated from at least one of said conductors;
(d) means for causing said contact assembly to move from said first position to said second position, thereby causing said contact assembly to be separated from at least one of said conductors thus interrupting current flow throiugh the switch and conversely from said second position to said first position, thereby causing said contact assembly to be in contact with each of said conductors thus providing a path for current flow through the switch;
(e) a piston of an insulating material extending from said contact assembly in assignment with the conductors of the bushings;
and
(f) an insulating gas in said housing maintained at a pressure of from about 1 to about 5 atmospheres absolute;
said switch being adapted to be electrically connected into an electrical power distribution system having a voltage in the range of from about 1 to about 36 kilovolts.

5 more elements

A single phase ground enclosed load break switch for use in electrical circuits in the voltage range of from about 1 to about 36 kilovolts which comprises:

(a) a sealed cylindrical housing comprises substantially of metal having a diameter in the range of from about 2 to about 6 inches (50-150 mm);
(b) first and second bushing means mounted so as to penetrate said cylindrical metal housing, one of said bushings being mounted proximate one end of said housing and the other being mounted proximate the other end of said housing, each of said bushings having an electrical conductor therethrough;
(c) a contact assembly capable of assuming a first position in which it is in physical and electrical contact with the electrical conductor of each of said bushings and a second position in which it is physically and electrically separated from at least one of said conductors;
(d) means for causing said contact assembly to move from said first portion to said second position, thereby causing said contact assembly to move out of electrical contact with one of said conductors and conversely from said second position to said first position, thereby causing said contact assembly to move into electrical contact with each of said conductors;
(e) an insulating gas in said housing maintainned at a pressure of about 1 to about 5 atmospheres;
and
(f) means for causing a flow of said insulating gas to the region between said contact assembly and the conductor as the contact assembly is moved into and out of contact with that conductor;
said switch being adapted to be electrically connected into an electrical power distribution system having a voltage in the range of from about 1 to about 36 kilovolts.

5 more elements

A single phase ground enclosed load break switch for use in electrical circuits in the voltage range of from about 1 to about 36 kilovolts which comprises:

(a) a sealed cylindrical housing comprised substantially of metal having a generally cylindrical side wall and a pair of opposing end walls, said housing diameter in the range of from about 2 to about 6 inches (50-150 mm);
(b) first and second bushing means coaxially penetrating said cylindrical metal housing, one of said bushings being mounted proximate one end of said housing and the other being mounted proximate the other end of said housing, each of said bushings having an electrical conductor therethrough;
(c) a contact assembly capable of assuming a first position in which it is in physical and electrical contact with the electrical conductor of each of said bushings and a second position in which it is physically and electrically separated from at least one of said conductors;
(d) a bellows consisting essentially of metal mounted in and hermetically sealed directly to the cylindrical side wall of the housing and having a lever extending therethrough, and hermetically sealed directly thereto, said bellows being capable of a "rocking" motion as said lever is moved with respect to the cylindrical wall, said lever being connected through a crank to said contact assembly;
(e) means acting on said lever to cause axial motion of said contact assembly from said first position to said second position, thereby causing said contact assembly to be separated from at least on of said conductors thus interrupting current flow through the switch and from said second position to said first position, thereby causing said contact assembly to be in contact with each of said conductors thus providing a path for current flow through the switch;
and
(f) an insulating gas in said housing maintained at a pressure of about 1 to about 5 atmospheres absolute;
said switch being adapted to be electrically connected between a load and a power course having a voltage in the range of from about 1 to about 36 kilovolts.

5 more elements

Dependencies are inferred from the claim text.

Load break switch

Life of this patent

Load break switch

Life of this patent

Abstract

Claims49