Siemens 38-3AH3 38 kV Overhaul, Circuit-breaker overhaul, Circuit breaker Number Type

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Overhaul

High-potential tests employ hazardous voltages.

Will cause death, serious injury and property damage.

Read instruction manual. All work must be performed with the circuit breaker completely de-energized and the springs discharged. Limit work to qualified personnel.

Introduction

The following procedures along with the troubleshooting charts at the end of this section, provide maintenance personnel with a guide to identifying and correcting possible malfunctions of the type 38-3AH3 vacuum circuit breaker.

Circuit-breaker overhaul

Table 5 gives the recommended overhaul schedule for a type 38-3AH3 vacuum circuit breaker. These intervals assume that the circuit breaker is operated under "usual service conditions" as discussed in ANSI/ IEEE C37.20.2, section 8.1 and ANSI/IEEE C37.04, section 4, and elaborated in ANSI/ IEEE C37.010, section 4.

When actual operating conditions are more severe, overhaul periods should occur more frequently. The counter on the front panel of the circuit breaker records the number of operations.

Circuit breaker		Number of
type		closings

38-3AH3		10,000

Table 5: Overhaul schedule

Replacement at overhaul

The following components are replaced during an overhaul of the circuit breaker, when required:

Vacuum interrupters as determined by vacuum-integrity test, contact erosion or after 10,000 operations

Spring-release coil, 52SRC

Shunt-trip coil, 52T

Auxiliary switch

Trip-free drive-bar mechanism.

When these parts are changed, locking devices must also be removed and replaced. These include lock washers, retaining rings, retaining clips, spring pins, cotter pins, etc.

1.Replace vacuum interrupters, instructions follow (refer to page 49).

2.Spring-release coil (52SRC) or shunt- trip coil (52T).

A.Remove two "push on" terminal connections

B.Remove two M4 hex-head screws and dismount solenoid.

C.Install replacement solenoids with two M4 hex-head screws and new lock washers.

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Contents

Answers for energy Qualified person Table of contents Introduction Signal words Hazardous ProceduresIntroduction Introduction Field service operation and warranty issuesShipping damage claims Introduction Receiving procedureReceiving, handling and storage Receiving, handling and storage Handling procedureIndoor storage Storage procedureOutdoor storage Space heatingDe-energizing control power in switchgear Installation checks and functional testsInspections, checks and tests without control power Installation checks and functional tests Type 38-3AH3 vacuum circuit breaker racking Racking crank engagement procedureManual-spring charging check Physical inspectionsSplit-plug jumper connected to circuit breaker Final mechanical inspections without control powerVacuum interrupter/ operator Vacuum interrupters Vacuum interrupter/ operatorStored-energy operating mechanism Phase barriersPrimary disconnects Construction Interrupter/operator moduleSwitching operation Current-path assemblyCircuit-breaker pole Vacuum interrupterType 38-3AH3 vacuum circuit breaker pole section Stored-energy operating mechanism Mode of operation Auxiliary switchOperating mechanism Indirect releases tripping coilsUse of manual-spring operation crank ClosingOpening Trip-free functionalityRapid auto-reclosing Manual operation62.2 62.5.2 50.3.1 53.0 Pawl roller 62.5.2 Close-latch pawl Vacuum interrupter/ operator Discharged Closing Standard Undervoltage optional Indirect releases dual-trip orSecondary shunt release optional 54.2Position a locked Secondary disconnect Capacitor-trip deviceShock absorber Truck-operated cell TOC switch Mechanism-operated cell MOC switch optionalShutter-operating linkage Secondary disconnect Shutters Rating interlock Trip-free interlockCircuit-breaker frame Ground disconnectVehicle function and operational interlocks Racking mechanismAlignment Interlocks Circuit breaker racking-interlocksRacking interlocks Closed circuit breaker interlock Automatic closing-spring energy release Trip-free interlock position mechanical interlock Introduction and maintenance intervals MaintenanceRecommended hand tools MaintenanceInspection items and tests Recommended maintenance and lubricationCleanliness check Removal from switchgearChecks of the primary power path Circuit Number Maintenance and lubricationInspection of primary disconnects Checks of the stored-energy operator mechanismTypical for all three-phases Manual-spring charging and contact- erosion checks Fastener checkAutomatic spring-charging check control power required Wiring and terminals checkElectrical-control checks Secondary-disconnect checkTypical vacuum interrupter contact curve Vacuum-interrupter mechanical check Spring-charging motor checksHigh-potential test voltages Vacuum-integrity check using dielectric testHigh-potential tests Voltage Frequency withstand Field-test voltageContinuous Contact Inspection and cleaning of circuit- breaker insulationRating a Functional testsOverhaul Replacement at overhaulCircuit-breaker overhaul Circuit breaker Number TypeOverhaul Vacuum interrupter replacementSetting Vacuum interrupter replacement illustration Overhaul Hydraulic shock absorber Checking the contact stroke Open the circuit breakerSub-assembly Inspect for Maintenance and troubleshootingProblem Symptoms Possible causes and remedies Maintenance and troubleshootingClosed Appendix Appendix Maximum design voltage Permissible tripping delay YValues Voltage Voltage range factor K3 Insulation Withstand Voltage levels Lightning-impulse BILLevels Voltage levels Lightning-impulse BIL Rated Maximum design voltageRated Continuous4 Short-circuit at rated maximum design voltage I5, 6Remarks Appendix