Siemens 38-3AH3 38 kV Racking mechanism, Vehicle function and operational interlocks, Alignment

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Vacuum interrupter/ operator

When circuit breakers are located above floor level, handling of the circuit breakers requires the use of a lifting device or a crane with a lift sling.

Racking mechanism

Figure 33: Circuit-breaker compartment (MOC/TOC switch cover removed for photo) on page 34 shows the racking mechanism in the switchgear used to move the circuit breaker among the DISCONNECT, TEST and CONNECT positions. This mechanism contains a circuit-breaker racking-block that mates with the bottom of the circuit-breaker housing, and locks the circuit breaker to the racking mechanism during in and out movement.

A racking crank (refer to Figure 2: Type 38- 3AH3 vacuum circuit breaker racking on page 11) mates to the threaded square- shaft of the racking mechanism. Clockwise rotation of the crank moves the circuit breaker into the switchgear, and counterclockwise rotation removes it.

The racking and trip-free interlocks provide several essential functions.

1.They prevent racking a CLOSED circuit breaker into or out of the switchgear assembly.

2.They discharge the closing springs whenever the circuit breaker is inserted into or withdrawn from the switchgear.

3.They prevent closing of the circuit breaker unless it is in either the TEST or CONNECT positions, and the racking crank is not engaged.

The rating interlock prevents insertion of a lower-rated circuit breaker into a cubicle intended for a circuit breaker of higher ratings.

Vehicle function and operational interlocks

A type 38-3AH3 vacuum circuit breaker is comprised mainly of the vacuum interrupter/operator module fitted to a vehicle. This vacuum interrupter/operator module is an integral arrangement of operating mechanism, dielectric system, vacuum interrupters and means of connecting the primary circuit. The vehicle supports the vaccum interrupter/operator module, providing mobility and fully coordinated application in Siemens type GM38 switchgear.

Successful coordinated application of the fully assembled type 38-3AH3 vacuum circuit breaker is achieved through precise alignment in fixtures during manufacture, and important functional interlocking.

Alignment

All aspects of the circuit breaker structure impacting alignment and interchangeability are checked using master fixtures at the factory. Field adjustment will not normally be required.

Interlocks

Circuit breaker racking-interlocks

The vacuum interrupter/operator module, the vehicle portion of the circuit breaker and the racking mechanism in the switchgear all cooperate to provide important operational interlocking functions.

1. Rating interlock

The rating interlock consisting of a coded-interference plate is mounted on the vehicle (refer to Figure 32: Circuit- breaker interlocks and ground disconnect on page 33). A mating- interference blocking plate is mounted in the drawout compartment (refer to Figure 33: Circuit-breaker compartment (MOC/TOC switch cover removed for photo on page 34).

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Contents Answers for energy Qualified person Table of contents Signal words Hazardous Procedures IntroductionIntroduction Field service operation and warranty issues IntroductionIntroduction Receiving procedure Receiving, handling and storageShipping damage claims Handling procedure Receiving, handling and storageStorage procedure Indoor storageOutdoor storage Space heatingInstallation checks and functional tests Inspections, checks and tests without control powerDe-energizing control power in switchgear Installation checks and functional tests Racking crank engagement procedure Type 38-3AH3 vacuum circuit breaker rackingPhysical inspections Manual-spring charging checkFinal mechanical inspections without control power Split-plug jumper connected to circuit breakerVacuum interrupter/ operator Vacuum interrupter/ operator Vacuum interruptersPhase barriers Primary disconnectsStored-energy operating mechanism Interrupter/operator module ConstructionCurrent-path assembly Switching operationCircuit-breaker pole Vacuum interrupterType 38-3AH3 vacuum circuit breaker pole section Stored-energy operating mechanism Auxiliary switch Mode of operationOperating mechanism Indirect releases tripping coilsClosing Use of manual-spring operation crankTrip-free functionality OpeningRapid 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 Indirect releases dual-trip or Undervoltage optionalSecondary shunt release optional 54.2Position a locked Capacitor-trip device Shock absorberSecondary disconnect Mechanism-operated cell MOC switch optional Truck-operated cell TOC switchShutter-operating linkage Secondary disconnect Shutters Trip-free interlock Rating interlockCircuit-breaker frame Ground disconnectRacking mechanism Vehicle function and operational interlocksAlignment Interlocks Circuit breaker racking-interlocksRacking interlocks Closed circuit breaker interlock Automatic closing-spring energy release Trip-free interlock position mechanical interlock Maintenance Introduction and maintenance intervalsMaintenance Recommended hand toolsRecommended maintenance and lubrication Inspection items and testsRemoval from switchgear Checks of the primary power pathCleanliness check Maintenance and lubrication Circuit NumberInspection of primary disconnects Checks of the stored-energy operator mechanismTypical for all three-phases Fastener check Manual-spring charging and contact- erosion checksWiring and terminals check Automatic spring-charging check control power requiredElectrical-control checks Secondary-disconnect checkTypical vacuum interrupter contact curve Spring-charging motor checks Vacuum-interrupter mechanical checkVacuum-integrity check using dielectric test High-potential testsHigh-potential test voltages Field-test voltage Voltage Frequency withstandInspection and cleaning of circuit- breaker insulation Continuous ContactRating a Functional testsReplacement at overhaul OverhaulCircuit-breaker overhaul Circuit breaker Number TypeVacuum interrupter replacement OverhaulSetting Vacuum interrupter replacement illustration Overhaul Checking the contact stroke Open the circuit breaker Hydraulic shock absorberMaintenance and troubleshooting Sub-assembly Inspect forMaintenance and troubleshooting Problem Symptoms Possible causes and remediesClosed Appendix Appendix Permissible tripping delay Y Maximum design voltageValues Voltage Voltage range factor K3 Insulation Withstand Voltage levels Lightning-impulse BILRated Maximum design voltage Levels Voltage levels Lightning-impulse BILRated Continuous4 Short-circuit at rated maximum design voltage I5, 6Remarks Appendix

38-3AH3 38 kV specifications

The Siemens 38-3AH3 is a high-voltage circuit breaker designed for medium voltage applications, particularly in substations and industrial environments. This device operates at a voltage level of 38 kV, showcasing Siemens' commitment to innovation and reliability in electrical engineering.

One of the main features of the Siemens 38-3AH3 is its advanced interruption technology, which employs the proven hybrid design combining both gas-insulated and air-insulated technologies. This hybrid approach not only enhances the breaker's performance and reliability but also minimizes its footprint, making it an ideal choice for space-constrained environments.

The Siemens 38-3AH3 uses vacuum interruption technology, allowing for efficient switching with minimal wear and tear. The vacuum interrupters are highly reliable and provide excellent performance under various operating conditions. This technology ensures that the circuit breaker can handle short circuits and overloads effectively, thus protecting the entire electrical system.

Additionally, the Siemens 38-3AH3 incorporates intelligent monitoring systems. These digital technologies provide real-time data on breaker status, operational performance, and maintenance needs. This predictive maintenance capability helps operators to identify potential issues before they develop into significant problems, ultimately leading to reduced downtime and maintenance costs.

Another notable characteristic of the Siemens 38-3AH3 is its high insulation strength. Thanks to its robust design and development, this circuit breaker can withstand adverse environmental conditions, making it suitable for use in diverse geographical locations and climates. Its components are designed to resist contamination and corrosion, ensuring long-term reliability.

The Siemens 38-3AH3 also offers enhanced safety features. It includes protective relays and automatic fault detection systems that isolate faults quickly, preventing damage to downstream equipment. Furthermore, the design allows for easy maintenance, with components that are accessible without the need for extensive disassembly.

In summary, the Siemens 38-3AH3 38 kV circuit breaker is a leading solution in high-voltage protection and control, characterized by its advanced interruption technology, integrated monitoring systems, high insulation strength, and user-friendly maintenance features. Its innovative design and engineering make it a trusted choice for utilities and industrial facilities aiming to enhance the reliability and safety of their electrical systems.
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