Siemens 38-3AH3 38 kV Mechanism-operated cell MOC switch optional, Truck-operated cell TOC switch

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Vacuum interrupter/ operator

 

6

5

4

3

2

1

 

 

1.

Ground disconnect

 

 

 

4.

CLOSED circuit-breaker racking interlock

 

 

2.

Spring-dump interlock

 

 

 

5.

Circuit-breaker frame

 

 

3.

Trip-free interlock

 

 

 

6.

Rating interlock

 

 

 

 

 

Figure 32: Circuit-breaker interlocks and ground disconnect

Figure 30: MOC switch operating

 

 

 

 

 

 

 

arm on a circuit breaker

The auxiliary switch contains both "b" (normally closed) and "a" (normally open) contacts. When the circuit breaker is OPEN, the "b" switches are closed and the "a" switches are open.

Mechanism-operated cell (MOC) switch (optional)

Figure 30: MOC switch operating arm on a

circuit breaker and Figure 31: MOC (bottom) and TOC (top) switches and associated terminal blocks show the principal components that provide optional-control flexibility when operating the circuit breaker in the TEST (optional) and CONNECT (standard) positions.

Figure 30: MOC switch operating arm on a circuit breaker shows the MOC-switch operating arm that projects from the right side of the circuit breaker, above the bottom rail structure. The MOC-switch operating arm is part of the jack-shaft assembly and directly reflects the OPEN or CLOSED position of the circuit breaker primary contacts.

As the circuit breaker is racked into the appropriate position inside the switchgear, the MOC-switch operating arm engages the pantograph linkage (refer to Figure 33: Circuit-breaker compartment (MOC/TOC switch cover removed for photo) on page 34). Operation of the circuit breaker causes the pantograph linkage to transfer motion to the MOC switches located above the pantograph.

The "a" and "b" contacts can be used in relaying and control-logic schemes.

All circuit breakers contain the MOC-switch operating arm. However, MOC switches are provided in the switchgear only when specified.

The circuit breaker engages the MOC switch only in the CONNECT (operating) position unless an optional TEST position pickup is specified in the contract. If a TEST position pickup is included, the circuit breaker will engage the auxiliary switch in both positions. Up to 24-stages may be provided.

Truck-operated cell (TOC) switch

Figure 31: MOC (bottom) and TOC (top) switches and associated terminal blocks shows the optional TOC switch. This switch is operated by the circuit breaker as it is racked into the CONNECT position.

Various combinations of "a" and "b" contacts may be optionally specified. These switches provide control and logic indication that a circuit breaker in the cell has achieved the CONNECT (ready-to- operate) position.

Figure 31: MOC (bottom) and TOC (top) switches and associated terminal blocks

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Contents Answers for energy Qualified person Table of contents Signal words Hazardous Procedures IntroductionIntroduction Introduction Field service operation and warranty issuesIntroduction Receiving procedure Receiving, handling and storageShipping damage claims Receiving, handling and storage Handling procedureIndoor storage Storage procedureOutdoor storage Space heatingInstallation checks and functional tests Inspections, checks and tests without control powerDe-energizing control power in switchgear 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/ operatorPhase barriers Primary disconnectsStored-energy operating mechanism 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 Capacitor-trip device Shock absorberSecondary disconnect 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 lubricationRemoval from switchgear Checks of the primary power pathCleanliness check 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 checksVacuum-integrity check using dielectric test High-potential testsHigh-potential test voltages 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

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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