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Air Circuit Breaker

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Air Circuit Breaker I.B. 32-150-3 RECEIVING • OPERATION • MAINTENANCE "De-ion" ; • f AIR CIRCUIT BREAKER i ; -vji Type DH m ! Type Kv Amps Kva Vi* i i| 50-DH-250 5.0 1200 250,000 50-DH-250 5.0 2000 250,000 75 DH 150 7.5 600 150,000 / - - 75-DH-150 7.5 1200 150,000 75-DH-250 7.5 1200 250,000 I ; 75 DH ? 250 7.5 2000 .1 - - 250,000 '' 2 ' 75-DH-500 7.5 1200 500,000 75-DH-500 7.5 2000 500,000 150 DH 150 15.0 600 150,000 3 - - 150-DH-250 15.0 1200 250,000 150-DH-500 15.0 1200 500,000 150-DH-500 15.0 2000 500,000 ! . At T • , : ELECTRIC 4 WESTINGHOUSE CORPORATION SWITCHGEAR AND CONTROL DIVISION EAST PITTSBURGH WORKS EAST PITTSBURGH, PA. { NEW INFORMATION EFFECTIVE OCTOBER, 1947 (R*p. 3-49) Printed In U S,A. * A e • N \ 4 1 i o i f w o One of the outstanding improvements in modern power distribution has been the “development of the air circuit breaker by Westinghouse for distribution circuit voltages. On circuits where the duty on breakers is heavy, long life with a minimum of maintenance makes the "De-ion 7 ' air breaker an outstanding performer. In the type DH magnetic "De-ion" air circuit breakers, Westing- house offers a complete standard line for circuits from 2.3 to 15 kv. This instruction book applies to breakers for the 7.5 and 15 kv classes and to 5 kv, 250,000 kva breakers which have the same class of insulation and general construction. Each of the type DH air circuit breakers is three-pole, electrically operated, and is built as a complete horizontal drawout unit for metal-clad switchgear. Breaker units of the same rating are interchangeable so that changing breakers f is a matter of minutes. Since they are drawn out horizontally, no lowering or lifting is necessary. Steel barriers and automatic interlocks prevent contact with live parts while the breakers are being changed. As in the case of most high voltage electrical equipment, these breakers should be inspected and maintained at regular intervals in order to obtain the most dependable performance. 3 2 | I mm :1W - I.B. 32-150-3 AIR CIRCUIT BREAKER !1 DESCRIPTION The type DH air circuit breaker is a three-pole, rier between personnel and live parts when the electrically operated, horizontal drawout unit for unit is in the cell. This barrier assembly is in two metal-clad switchgear. In the type designation, parts for convenience in handling. the numbers preceding DH indicate the voltage rating in hundreds of volts, and the numbers follow- * ing DH indicate the maximum interrupting rating CHUTE in thousands of kva. The various ratings have A ARC similar many parts in l . r structural features and i * common. P- 1 BLOWOUT Fig. 1 shows a type 150DH250 breaker with -MAGNET the main barrier assembly and one arc chute re- CONDENSER moved. This shows clearly the arrangement of the - BUSHING FINGER arc chutes and blowout magnet assemblies, the con- CONTACTS tacts and insulated operating rods, and the sole- A noid operating mechanism These components are MOVING . CONTACT ARM supported in a welded steel frame mounted on flanged wheels for guiding it into the metal clad OPERATING - TRIPPING ROD cell. In the lower part of the frame also is located TRIGGER- the levering-in device for moving the breaker into final contact engagement. This device is inter- SOLENOID locked with the mechanism to prevent inserting or MECHANISM withdrawing the breaker with the contacts closed. Also located in the lower part of the frame are the secondary contacts for automatically disconnecting the control wiring when the breaker is withdrawn, the auxiliary switch, and other auxiliary devices. TRIP COIL A barrier assembly is placed on the breaker before it is rolled into its . The front sheet is cell of FIG. 1. Type 150 DH 250 Circuit Breaker with Main one-eighth inch steel to form a grounded bar- Barrier and One Arc Chute Removed. RECEIVING, HANDLING, STORING All type DH breakers are completely assem- damaged, file a claim immediately with the carrier bled and given operating tests at the factory, and notify the nearest Westinghouse Sales office. after which they are carefully inspected and pre- pared for shipment by workmen experienced in HANDLING the proper handling and packing of electrical equipment. In order to afford maximum protection Remove the crating and packing carefully to against damage, the main barrier assembly and the avoid damage from negligent handling of crowbars arc chutes are removed from the breaker and or other tools. Use a nail puller for the uncrating. packed separately. For each three-pole breaker Care must be used in handling the arc chutes, there is one barrier assembly and three arc chutes. since the splitter plates within them are made After the equipment has been unpacked, make of a ceramic material which may break if dropped. a careful inspection for any damage which may have The base of the crate may be used as a skid for occurred in transit. If the apparatus has been moving the breaker, or the breaker may be lifted 3 RECEIVING, HANDLING AND STORING. with sling under the crate. If the breaker is to be STORING lifted with slings, move it while it is still crated. The arcing chambers shipped After the breaker is unpacked, the best way to are in separate containers to guard against damage move it is by rolling it on its own wheels. from rough handling and for better protection If it is necessary to lift the breaker after it is from dust and water or liquids i uncrated, lift it without the arc chutes or barriers . Store them in their shipping containers until ready in place. Slings may be placed under the breaker for use. frame or in holes provided in the frame. Use a Store all components of these breakers in a clean spreader to prevent the cables from distorting the dry place. During the storage period, keep them blowout magnets. sufficiently warm to prevent moisture condensation. TABLE OF WEIGHTS (POUNDS) TYPE BREAKER UNIT ARC CHUTE (Each) BARRIER ASSEMBLY 75-DH-150 1175 57 150 75-DH-250 1400 65 160 75-DH-500 1600 105 160 150-DIM 50 1175 57 150 150-DH-250 1250 70 160 150-DH-500 1450 105 160 INSTALLATION With the exception of the arcing chambers and or excessive friction. As the contacts touch near the barriers, these breakers are shipped completely end of the closing stroke, the force necessary to close assembled and adjusted. No adjustments should be the breaker increases rapidly. obviously required and none should be made unless 2. With the breaker in the closed position, check needed. the contacts to make certain that the adjustments When the breaker has been removed from the have not been disturbed. Refer to Fig. 2 for proper crate, remove the wooden clamp and angle iron settings. If adjustments are required, they may be braces which support the blowout magnet pole made as described under OPERATION AND AD- pieces during shipment and the breaker is ready JUSTMENTS. assembly for final . A light film of grease is applied to both the arcing Caution: Severe injury may be sustained and main contacts before the breaker is operated if any part of the body is struck by the con- at the factory. This film is normally removed before tact arms since they move very rapidly on the shipment. Before the breaker is placed in service, opening stroke. Personnel working about the inspect the arcing contacts to see that they are free breaker should stay clear of the space in which of oil or grease. the arms move while is contact breaker 3 The breaker is more easily handled with the being . closed or is closed. arc chutes and barriers removed; mount these parts The following sequence of operations should be after the breaker has been moved near the metal- performed in preparing the breaker for use: clad cell structure. 1. Breakers are usually shipped with the con- Before installing the arc chutes, play a stream of tacts closed and with a tie on the trip lever to pre- dry compressed air through them from each end to vent tripping. After the breaker is unpacked and remove any dust or foreign matter. Then examine the shipping ties and braces removed, take off the the chutes to make certain that the vents and slots tie on the trip lever and trip the breaker. Then close are open and free from foreign material. Assemble the breaker carefully by hand, using the emergency the arc chutes on the breaker by removing the re- hand closing lever. Make certain that all parts are taining straps from the front of the magnet pole functioning properly and that there is no binding pieces and sliding the chutes into position, making o 4 INSTALLATION. I.B. 32-150-3 AIR CIRCUIT BREAKER the top of the laminated pole faces. Connect the STATIONARY MOVING |II TQ |11 shunt strap to the front arcing horn in the chute. ARCING CONTACT 16 ' 16 ARCING CONTACT ARCING ^ MOVING Tighten the lower connection of the shunt strap CONTACT SPRINGS ^CONTACT ARM / STATIONARY since it may have loosened during transit. The arc ARCING SECONDARY CONTACT ^jCONTACT SHUNT V chute is now completely installed. - MOVING Make a final SECONDARY CONTACT check by operating the breaker slowly by hand to — PUFFER )K CYLINDER see that there is no interference in the movement of the moving contact.
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