Siemens 38-3AH3 38 kV Operating mechanism, Indirect releases tripping coils, Auxiliary switch

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Vacuum interrupter/ operator

When a tripping command is given, the energy stored in the tripping- and contact- pressure springs is released by pawl (64.2). The opening sequence is similar to the closing sequence. The residual force of the tripping spring arrests the moving contact (36.0) in the OPEN (TRIPPED) position.

Operating mechanism

The operating mechanism is comprised of the mechanical and electrical components required to:

1.Charge the closing springs with sufficient potential energy to close the circuit breaker and to store opening energy in the tripping- and contact- pressure springs.

2.Means to initiate closing and tripping actions.

3.Means of transmitting force and motion to each of three poles.

4.Operate all of these functions automatically through electrical- charging motor, cutout switches, anti- pump relay, release (close and trip) solenoids and auxiliary switches.

5.Provide indication of the circuit breaker status (OPEN/CLOSED), spring condition (CHARGED/DISCHARGED) and number of operations.

Construction

The essential parts of the operating mechanism are shown in Figure 15: Stored-energy operating mechanism on page 20. The control and sequence of operation of the mechanism is described in the Operating mechanism section diagrams in Figure 17-21 on pages 24 through 28.

Indirect releases (tripping coils)

The shunt releases (54.1) convert the electrical-tripping pulse into mechanical energy to release the trip latch and open the circuit breaker.

The undervoltage release (optional) (54.2) may be electrically actuated by a make or a break contact.

If a make contact is used, the coil is shorted out, and a resistor must be used to limit the current. The undervoltage-release option mounts to the immediate right of the trip coil (54.1).

Motor-operating mechanism

The spring-charging motor (50.4) is bolted to the charging-mechanism (50.2) gear box installed in the mechanism housing. Neither the gear-box mechanism nor the motor require any normal maintenance.

Auxiliary switch

The auxiliary switch (68.0) is actuated by the jack shaft (63.0) and link (68.1).

Mode of operation

The operating mechanism is of the stored- energy trip-free type. In other words, the charging of the closing spring is not automatically followed by the contacts changing position, and the tripping function prevails over the closing function in accordance with ANSI/IEEE C37.04- 1999, clause 6.9.

When the stored-energy mechanism has been charged, the circuit breaker can be closed manually or electrically at any desired time. The mechanical energy for carrying out an "open-close-open" sequence for auto-reclosing duty is stored in the closing and tripping springs.

Charging

The details of the closing-spring charging mechanism are shown in Figure 15: Stored-energy operating mechanism on page 20. The charging shaft is supported in the charging mechanism (50.2), but is not coupled mechanically with the charging mechanism.

Fitted to it are the crank (62.2) at one end, and the cam (62.3), together with lever (62.5) at the other.

When the charging mechanism is actuated by hand with a hand crank or by a motor (50.4), the flange (50.3) turns until the driver (50.3.1) locates in the cutaway part of the cam disc (62.3), thus causing the charging shaft to follow. The crank (62.2) charges the closing spring (62.0).

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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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