LV Air Circuit Breaker Maintenance & Testing

LV Air Circuit Breaker Technical Description, Maintenance Procedure and Testing.

acv

ACV Parts

Schedule  Maintenance Check list

Power Portion of the ACB (1)Cleaning( with CRC) and tightness checking of –

Power contacts or jaw contacts and all other parts.

(2)Check condition of arcing contact and gap between fixed and moving arcing contracts shall be checked.

(3)Checking condition and alignment of jaw contract with cradle terminals.

(4)Checking proper closing of all poles together.

(5) Checking condition of arc chutes.

 (5) Checking presence of all circlips

(6) Replacement of broken or damages parts if any.

Operating Mechanism  of the ACB (1)Cleaning( with CRC), tightness, greasing & adjustment of-

(a)  Spring charging motor & its gear mechanism.

(b)  Motor limit switch assembly.

(c)   Closing coil & its assembly.

(d)  Tripping coil & its assembly.

(e)  Tripping coil no. 2 if any available.

(f)    Auxiliary contacts

(g)  Main shaft /operating rod

(h)  Closing, tripping & other springs.

(i)     Control block of the breaker.

(2)Checking ACB tripping through Shunt release.

(3)Checking continuity and proper changeover of aux contract block.

(4) setting of-

             (a) All spring tension

             (b) all levers

(5) Replacement of broken or damages parts if any.

Trolley/truck of the ACB (1)Cleaning( with CRC), tightness, greasing & adjustment of-

  (a) All four trolley wheels.

   (b) Rack in and rack out mechanism.

   (c) Metallic Body parts.

   (d) Earthings.

(3) Replacement of broken or damages parts if any.

 

Front Panel Portion Of the ACB (1)Cleaning( with CRC), tightness, greasing & adjustment of-

   (a) Shutter mechanism.

   (b) Service, test & door limit switches positions.

(3) Replacement of broken or damages parts if any.

 

Field Testing of Air Circuit Breaker:

  • Insulation resistance Test:(R. Values for 60/15 seconds, with 500V, I.R Tester, commonly known as Megger)
  • Checking IR between phases – phase (ACB Closed condition).
  • Checking IR between phases – earth (ACB closed Condition).
  • Checking IR between phases – earth (ACB in open condition).

 

  • Power contacts or jaw contacts continuity of all three poles.
  • Contacts Resistance Measurement in micro ohms.

 

 

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