Siemens 38-3AH3 38 kV Trip-free functionality, Opening, Rapid auto-reclosing, Manual operation

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Trip-free functionality

Refer to Figure 15: Stored-energy operating mechanism on page 20, Figure

17:Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED on page 24, Figure 18: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism OPEN, closing spring DISCHARGED on page 25, Figure 19: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism CLOSED, closing spring DISCHARGED on page 26 and Figure 20: Operating mechanism section diagram (drawout trip-free linkage shown) mechanism CLOSED, closing spring CHARGED on page 27.

The trip-free coupling rod (62.8) permits the immediate de-coupling of the drive lever (62.6) and the jack shaft (63.0) to override the closing action by trip command or by means of the racking interlocks.

The trip-free coupling rod (62.8) forms a link between the drive lever (62.6) and the jack shaft (63.0). The rigidity of this link depends upon a spring-return latch carried within the coupling rod.

The latch pivots within the coupling rod and is normally positioned to maintain the rigidity of the coupling rod.

Trip-free coupling link (62.8.2) and trip- free coupling lever (62.8.3) cause the spring-return latch position to be dependent upon the normal tripping components and the racking interlock.

Thus, whenever a trip command is applied or the circuit breaker is not in the fully CONNECT or TEST position, the trip-free coupling rod is no longer rigid, effectively de-coupling the drive lever and jack shaft. Under these conditions the vacuum interrupter contacts cannot be closed.

Vacuum interrupter/ operator

Opening

If the circuit breaker is to be tripped locally, the tripping spring (64.0) is released by pressing the trip button (54.0). In the case of an electrical command being given, the shunt-trip coil 52T (54.1) unlatches the tripping (opening) spring (64.0). The tripping spring turns the jack shaft (63.0) via lever (63.5); the sequence being similar to that for closing.

Rapid auto-reclosing

Since the closing spring is automatically recharged by the motor-operating mechanism when the circuit breaker has closed, the operating mechanism is capable of an "open-close-open" duty cycle as required for rapid auto-reclosing.

The circuit breaker is suitable for use in applications with a rated reclosing-time interval of 0.3 seconds, per ANSI/IEEE C37.06-2009.

Manual operation

Electrically-operated vacuum circuit breakers can be operated manually if the control supply should fail.

Manually charging the closing spring

Refer to Figure 16: Use of manual-spring operation crank on page 22. Insert the hand crank (50.0) in hole (50.1) and turn it clockwise (about 48 revolutions) until the indicator (55.0) shows CHARGED. The hand crank is coupled with the charging mechanism via an over-running coupling; thus the operator is not exposed to any risk should the control supply be restored during charging.

Manual closing

To close the circuit breaker, press the close button (53.0). The OPEN/CLOSED indicator (55.0) will then display CLOSED and the closing-spring condition indicator (58.0) will now read DISCHARGED.

Manual opening

The tripping spring is charged during closing. To open the circuit breaker, press the trip button (54.0) and OPEN will be displayed by indicator (55).

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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 procedureSpace heating Storage procedureIndoor storage Outdoor storageDe-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 moduleVacuum interrupter Current-path assemblySwitching operation Circuit-breaker poleType 38-3AH3 vacuum circuit breaker pole section Stored-energy operating mechanism Indirect releases tripping coils Auxiliary switchMode of operation Operating mechanismUse of manual-spring operation crank ClosingManual operation Trip-free functionalityOpening Rapid auto-reclosing62.2 62.5.2 50.3.1 53.0 Pawl roller 62.5.2 Close-latch pawl Vacuum interrupter/ operator Discharged Closing Standard 54.2 Indirect releases dual-trip orUndervoltage optional Secondary shunt release optionalPosition a locked Secondary disconnect Capacitor-trip deviceShock absorber Truck-operated cell TOC switch Mechanism-operated cell MOC switch optionalShutter-operating linkage Secondary disconnect Shutters Ground disconnect Trip-free interlockRating interlock Circuit-breaker frameInterlocks Circuit breaker racking-interlocks Racking mechanismVehicle function and operational interlocks AlignmentRacking 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 Checks of the stored-energy operator mechanism Maintenance and lubricationCircuit Number Inspection of primary disconnectsTypical for all three-phases Manual-spring charging and contact- erosion checks Fastener checkSecondary-disconnect check Wiring and terminals checkAutomatic spring-charging check control power required Electrical-control checksTypical 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 voltageFunctional tests Inspection and cleaning of circuit- breaker insulationContinuous Contact Rating aCircuit breaker Number Type Replacement at overhaulOverhaul Circuit-breaker overhaulOverhaul 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 Voltage levels Lightning-impulse BIL Permissible tripping delay YMaximum design voltage Values Voltage Voltage range factor K3 Insulation WithstandShort-circuit at rated maximum design voltage I5, 6 Rated Maximum design voltageLevels Voltage levels Lightning-impulse BIL Rated Continuous4Remarks 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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