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

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

Contents

IB131009ENInstruction BookPage 26SECTION 5: DESCRIPTION ANDOPERATIONEaton Type W-VAC and W-VACW are horizontaldrawout circuit breakers while the W-VACR is a fixedcircuit breaker. They are all designed specifically to IEC56 and KEMA certified to IEC Standards, includ- ingtheir earthing system.W-VAC and W-VACW breakers are both available inthree mounting configurations. These include single tierdesigns and double tier designs for use in medal-cladswitchgear, and a basic element design for use in retro-fitting. For the single tier design, the basic breaker ele-ment is mounted on a carriage assembly. The basicbreaker element is mounted on a cradle assembly forthe double-tier design. The carriage assembly and thecradle assembly both incorporate the racking mecha-nism and required safety interlocks. The W-VACR fixedcircuit breaker is available for a single tier configurationonly.For drawout breakers, the basic breaker element, thebreaker element with a carriage assembly, and thebreaker element with a cradle assembly are designed toaccept a variety of faceplates or covers. This permitsthe breakers to be very flexible with respect to the typeof structure used to form the final switchgear assembly.Possibility 1 : The basic breaker element, by itself, isused for retrofitting purposes (Figures 3-3 and 3-4).Possibility 2: The basic breaker element combined witha carriage assembly is used for single tier switchgear.The breaker and carriage combination, however, can beutilized in a flush mounted configuration (Figure 5-1) ora behind the door configuration. The flush mounteddesign cover forms a deadfront design with the struc-ture, once the breaker is racked into the fully connectedposition.Possibility 3 :The basic breaker element combined witha cradle assembly is used for double tier switchgear.This combination is only for use in a behind the doorconfiguration (Figure 5-2).W-VAC breakers utilize Eaton vacuum inter- rupters toclose and open the primary circuit. The mech- anism isa front mounted, spring stored energy type, which iscommon to all ratings. This one front mountedmechanism is easy to inspect, accessible for servicingand requires a minimum of spare parts. Because of theinherent long life characteristics of the vacuum inter-rupters and the highly reliable spring stored energymechanism, W-VAC and W-VACW circuit breakers pro-Figure 5-1 Flush mounted configuration.vide long trouble free service with a minimum of mainte-nance.The primary insulation used throughout both breakerdesigns is flame retardant and track resistant glass poly-ester.5-1 INTERRUPTER ASSEMBLYVacuum interrupters are mounted vertically and support-ed from the fixed stem clamped to the top conductor(Figure 5-3 for W-VAC) and (Figure 5-9 for W-VACW).The current transfer system consists of a series of tin-plated, high-conductivity copper leaf conductors that arepressed onto the movable interrupter stem.This pro-vides a multipoint contact resulting in low electrical andthermal resistance. Since the current transfer from themovable stem to the breaker main conductor is a non-sliding design, no maintenance is required.5-1.1 VACUUM INTERRUPTERAll the circuit breakers utilize vacuum interrupters forinterruption and switching functions. The primary differ-ence between the different breaker types is the vacuuminterrupter configuration, which results in different rat-ings (Tables 1.1 and 1.2). Vacuum interruption offersthe advantages of enclosed interrupters, reduced sizeand weight, short interrupting time, long life, reduced