Workscope: LVCB Major Overhaul and Conversion

• The circuit breaker will be received and inspected for worn, damaged and missing components
  

  -	Inspection includes, but is not limited to, broken secondary disconnects, bent or damaged interlock arms, rusting on the frame, bent primary disconnects, and missing hardware.
  -	Any item found damaged will be recorded and a suitable replacement identified.

• Arc chutes will be removed, cleaned and inspected for erosion and damage
  

  -	Arc chutes will be inspected for chipped or broken components, and for excessive pitting or burning in the arc path.
  -	Where available, arc chutes as well as other components containing asbestos should be replaced with the manufacturer's recommended non-asbestos parts. These asbestos replacement parts will be quoted at the customer's request.
  -	Upon request, GE will properly dispose off the asbestos-containing materials.

• The circuit breaker will be functionally and operationally tested to determine any additional work required
  

  -	The breaker will be operated and inspected for binding of moving components.
  -	Individual electrical components will be tested as required.
  -	The circuit breaker will be inspected for applicable manufacturer updates.
  -	Any additional work required will be quoted separately.

• The front and back frames will be separated to facilitate overhaul
  

  -	The circuit breaker wiring harness, if so equipped, will be removed to facilitate separation of the front and back frames.
  -	All interconnect links between the mechanism and the contact assem blies will be disassembled
  -	Front and back frames will be separated.

• The back frame, insulating parts and contact assemblies will be completely disassembled.
  

  -	Disassembly and cleaning of the contact structures reduces the amount of resistance in and heat generated by the current carrying path. This process also removes all of the dried lubrication found in the contact structure.
  -	The contact assemblies will be removed from the circuit breaker and disassembled into component parts.
  -	All contact assembly components will be inspected for damage and wear.
  -	All components will be cleaned and the contact structures re-assembled using extended life lubricants.
  -	After re-assembly, contact pressure will be checked and adjusted according to manufacturer's specifications.

• The back frame will be painted and the components assembled and lubricated with extended life lubricant
• Front frame and mechanism will be completely disassembled into component parts.
• The front frame and escutcheon will be thoroughly cleaned and painted.
• The operating mechanism will be disassembled and cleaned, and the trip shaft bearings and reset latch will be replaced
  

  -	Replacement of the trip shaft bearings and of the breaker reset latch increases the reliability of the breaker.
  -	The mechanism will be disassembled to component parts.
  -	All parts will be cleaned and inspected for wear or damage.
  -	The mechanism will be re-assembled and the trip shaft bearings and reset latch replaced with factory new parts.
  -	All sliding surfaces within the mechanism will be lubricated.

• The front frame and mechanism will be assembled and lubricated using extended life lubricant
• The circuit breaker's front frame and back frames will be assembled, and the appropriate conversion kit installed
  

  -	Replacement of old electro-mechanical trip devices to new current generation digital trip devices increases the flexibility and reliability of your existing circuit breakers.
  -	GE currently offers three different types of conversion kits: the MicroVersaTrip Plus™ (M or PM), the ProTrip and the Carriere conversion kit.
  -	The existing trip devices and components will be removed to make room for the conversion kit.
  -	The conversion kit will be installed according to manufacturer's specifications and all components verified for correct installation.

• Insulating parts will be thoroughly cleaned and inspected for damage
  

  -	Each phase barrier and insulating part will be cleaned with a solvent and inspected for damage.
  -	Any damaged parts will be replaced.

• Circuit breaker wiring will be cleaned and inspected
  

  -	The wiring bundle will be inspected for damaged or cut control wiring.
  -	Any replacement wiring, if needed, will be quoted separately.

• Mechanical adjustments will be checked and adjusted as required
  

  -	Wipe and gap measurements will be taken as required.
  -	Mechanism adjustments, such as trip latch wipe, will be completed according to manufacturer's specification.
  -	Quick close mechanism will be checked (if applicable).

• Interlocks, mechanical and electrical, will be checked and adjusted for proper operation, if necessary
• Breaker electrical accessory devices will be tested for proper operation (if applicable). Adjustments will be made as necessary
  

  -	Under voltage device
  -	Shunt trip
  -	Open fuse lock out device
  -	Bell alarm (with or without lock out device)
  -	Auxiliary switch

• Final electrical tests will be performed, as applicable
  

  -	High current injection tests - Each phase will be checked for over-current and fault protection provided by the trip device.
  -	Contact resistance tests - A digital low resistance ohmmeter will be used to record the contact resistance and compare it to the manufacturer's specifications. High resistance in the contact structure can cause excessive heat in the breaker and prematurely dry out the lubrication.
  -	Insulation resistance tests - A 500 to 1,000 volt megger will be used to determine the condition of the circuit breaker insulation to ground and across phases.
  -	Functional operational tests (electrical and manual) - The breaker will be electrically and manually operated.
  -	Contact overlap sequence tests (AKF field breakers only) - For generator field circuit breakers, the field contact overlap and sequence will be checked and adjusted according to GE specifications.

• Test data will be included as part of the final customer report
  

  -	All test data received will be included with the circuit breaker test report. The test report will be shipped with the equipment.

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