Siemens 3AH Anleitung Handbuch - Seite 28

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1. Table of Contents

Overhaul

Introduction

For following procedures along with the troubleshooti ng

charts at the end of this section, provide maintenance per

sonnel with a g u i d e to identifying a n d correcting possible

malfunctions of the circuit breaker.

A WARNING

Hazardous voltages and high speed moving

parts.

Can cause death, severe personal injury, or

property damage.

De-energize circuit breaker and discharge

springs before working on circuit breaker.

Read instruction manual.

Circuit Breaker Overh.aul

Table 6 lists the recommended overhaul schedu l e for 3AH

circuit breakers operating under ANSI usual cond itions.

When actual operating cond itions are more severe, over

haul periods should occur more frequently. The counter on

the front panel of the circuit breaker records the n u mber of

operations.

Table 6. Overhau l Schedu le

ANSI Usual Conditions

Maintenance Based Upon Number of Closing Operations

Circuit Breaker Type

kA(MVA)

5 kV

36kA (250MVA)

15 kV

23kA (500MVA)

All Others

Replacement at Overha u l

T h e following components a r e replaced d uring a n overha u l

of t h e circuit breaker, when req uired:

• Vacuum interrupters as determined by vacuum integrity

test, contact erosion, or accord ing to Overh a u l Sched u l e

- reference Table 6.

• Close Coil, 52SRC

•Tri p Coil, 52T

•Trip Free Drive Bar M echa nism

When these parts are cha nged, locking devices must a l so be

removed and replaced. These include lock washers, reta in

ing rings, retaining clips, spring pins, cotter pins, etc.

1. Replace Vacuum I nterrupter; instructions follow.

2. Close Coil (52SRC) andTrip Coil (52T).

a. Remove two "push on" terminal con nections

b. Remove two M4 hex head screws and coils.

c) I n stall replacement coils with new M4 x 1 0 hex head

screws (Siemens part # 00-000-443-820) and new lock

washers for M4 (Siemens part # 00-000-288-31 6) .

Number of

Closing Operations

30,000

10,000

d. T h e coil mounting screws must b e installed using

thread locking adhesive ( Loctite #222, Siemens part

1 5-1 33-281-007) and primer ( Loctite primerT, Siemens

part 1 5- 1 33-28 1-005) .

e) Connect wires to coils with new wire terminals

(Siemens part # 1 5- 1 7 1 -600-002)

3. Lubricate operating mechanism according to M a i ntenance

Section.

4. When work is finished operate circuit breaker, close

open, several times, and check that all screw con nec

tions are tight.

Replacement of Vacuum Interru pters

Replacement vacuu m interrupters are furnished as a

complete assembly. They have been completely tested a n d

dielectrically and mechanically conditioned.

For 3000A circuit breaker with flexible current shunts which

are electron-beam welded to the vacu u m i nterrupters, the

vacuum interrupters are not field replaceable. Contact the

nearest Siemens representative.

It is recommended that one vacuum interrupter be removed

and replaced com pletely rather than removing two or more

vacu u m interrupters at a time. The following procedure i n

check l ist format describes the procedure for removing a n d

replacing a vacuum interrupter. Components m a y b e identi

fied by reference to Figures

1. Removing the Vacuum Interrupter

N ote: Special care needs to be exercised in removal

or installation of hardware around the bottom, or mov

able contact end, of the vacuum interrupter.

The movable contact uses metal bellows to maintai n

the vacu um seal while still permitting u p and down

motion of the contact. These bellows a re rugged a n d

reliable, and a r e designed t o withstand years of verti

cal movement. However, care should be exercised

to avoid subjecting the bellows to excessive torq ue

du ring removal and replacement. Twisting the bellows

through careless bolt removal or tightening may dam

age the vacu um interrupter.

1.1 Before starting work, the circuit breaker should be

isolated from all primary and control power sources

and all stored energy discharged by opening,

closing, a n d opening the circuit breaker by h a n d .

Discharge a n y static charge b y grounding all a n d

center metal sections of t h e vacu um interru pter.

Ca refu lly remove exterior a n d interphase barriers.

1.2 Loosen the lateral bolt(s) on terminal clamp (29.2).

Refer to Figure 20 and employ the illustrated proce

d u re to loosen clamp hardware.

and 20.