Eaton W-VAC Series Instructions For Installation, Operation And Maintenance

Also see for 120W-VAC16: Instructions for installation, operation and maintenance

Contents

Instruction BookPage 29IB131009ENW-VAC, WVACR, and W-VACW designs utilizes contin-uous glass polyester moldings to support individual poleunits. All 95 KV BIL 630 through 1250 ampere ratedbreakers require an additional cover to be added to thesupport molding, resulting in the support molding beingenclosed on all four vertical sides (Figure 5-4a).All 3150 ampere breakers, no matter what the ratedvoltage or BIL level, utilize continuous one piece glasspolyester moldings to support and enclose individualpole units (Figure 5-4b). No additional covers arerequired as just described for 95 KV BIL 630 through1250 ampere rated breakers.5-2 STORED ENERGY MECHANISM5-2.2 CHARGINGFigure 5-6 is a schematic view of the spring chargingparts of the stored energy mechanism.The major component of the mechanism is a cam shaftassembly which consists of a drive shaft to which areattached two closing spring cranks (one on each end),the closing cam, drive plates, and a free-wheeling ratch-et wheel. The ratchet wheel is actuated by an oscillatingmechanism driven by the motor eccentric. As the ratchetwheel rotates, it pushes the drive plates which in turnrotate the closing spring cranks and the the closing camwith it.The closing spring cranks have spring ends connectedto them, which are in turn coupled to the closing springs.As the cranks rotate, the closing springs are charged.When the closing springs are completely charged, theKEEP HANDS AND FINGERS AWAY FROM THEBREAKER'S INTERNAL PARTS WHILE THE BREAK-ER CONTACTS ARE CLOSED OR THE CLOSINGSPRINGS ARE CHARGED. THE BREAKER CON-TACTS MAY OPEN OR THE CLOSING SPRINGS DIS-CHARGE CAUSING A CRUSHING INJURY. DIS-CHARGE THE SPRINGS AND OPEN THE BREAKERBEFORE PERFORMING ANY BREAKER MAINTE-NANCE, INSPECTION OR REPAIR.The spring stored energy operating mechanism isarranged vertically in front of all circuit breakers. Itincludes all the elements for storing the energy, closingand tripping of the breaker, as well as manual and elec-trical controls. The manual controls are all front accessi-ble. Motion to close and open the interrupter contacts isprovided through operating rods connecting the mecha-nism pole shaft to the bell cranks of the interrupterassemblies.5-2.1 OPERATION OF STORED ENERGYMECHANISMThe mechanism stores the closing energy by chargingthe closing springs. The mechanism may rest in any oneof the four positions shown in figure 5.5 and as follows:a. Breaker open, closing springs dischargedb. Breaker open, closing springs chargedc. Breaker closed, closing springs dischargedd. Breaker closed, closing springs chargedspring cranks go over dead center, and the closing stoproller comes against the spring release latch. The clos-ing springs are now held in the fully charged position.Closing springs may also be charged manually. Insertthe maintenance tool in the manual charging socket(Figure 4.1a). Move it up and down approximately 38times until a clicking sound is heard, and the closingsprings charging indicator indicates "Charged". Any fur-ther motion of the maintenance tool will result in freewheeling of the ratchet wheel.5-2.3 CLOSING OPERATIONFigure 5-5 shows the position of the closing cam andtripping linkage. Note that in Figure 5-5a in which thebreaker is open and the closing springs are discharged,the trip "D" shaft and the trip latch are in the unlatchedposition as in Figure 5-5b.The closing springs can be released to close the break-er by moving the spring release latch out of the way.This is done electrically or manually by depressing thespring release lever, which turns the spring release latchout of the way of the closing stop roller. The force of theclosing spring rotates the cam shaft through the springcranks. The closing cam, being attached to the camshaft, in turn rotates the pole shaft through the main linkto close the breaker.In Figure 5-5c the linkage is shown with the breaker inthe closed position before the closing springs have beenrecharged. Interference of the trip "D" shaft with the triplatch prevents the linkage from collapsing, and thebreaker is held closed.Figure 5-5d shows the breaker in the closed positionafter the closing springs have been recharged. Note thatthe spring charging rotates the closing cam by one halfWARNING