GE Industrial Solutions EntelliGuard G - Manual (Page 40)

EntelliGuard® G Circuit Breaker DEH-41304C
Section 8 – Maintenance, Testing and Troubleshooting 13 March 14
40 ©2012 General Electric All Rights Reserved
1. Inspect the arc splitter plates and sides of the moldings
for signs of wear or damage. Replace as necessary.
2. With the circuit breaker in the ON position, check the
size of the gaps between the fixed and moving arcing
contacts.
 If the gap is greater than 2.5 mm:
- No evidence of contact damage: loosen the
fixed contact screw and adjust the gap to
2.5 mm. Retighten the screw (12 N m torque).
- Evidence of excessive contact wear or damage:
Replace the fixed arcing contacts and set the
gap set to 2.5 mm.
 Even if gaps are within operating tolerance (1 mm
to 2.5 mm) always check contact screws for
tightness to 12 N m torque.
3. Assemble the arc chamber. Torque to 2 N m.
Circuit Breaker Main Mechanism Inspection
 Check the circuit breaker ON and OFF action both
manually and by remote means, if appropriate.
 Check tripping action by means of the under voltage
release (if installed).
 Check all indicators for correct function.
 Check number of operations (if operations counter is
installed) to the circuit breaker’s specification.
Cassette Inspection
 Ensure the base of the cassette is clear of debris.
 Prop open the top and bottom shutters and inspect the
cassette’s installed contacts for excessive wear or
damage.
 Check the carriage switch operation (if installed) while
racking the circuit breaker into and out of the
CONNECTED position.
Isolating Contacts (Drawout Type) Inspection
1. Remove the circuit breaker from the cassette housing
and place it on a suitable working surface.
2. Inspect the rear cluster contacts for signs of
overheating and wear.
3. Remove the cluster contacts using the special cluster
pliers.
4. Clean the isolating contacts and terminals with a soft,
clean cloth to remove any old grease or dirt.
5. Apply a thin film of white paraffin grease (grade 8802).
Power Terminals and Busbar Inspection
1. Inspect insulating parts for cracks. If found, replace
affected component.
2. Clean dust/dirt with dry cloth.
3. Tighten screws/nuts to proper torque.
4. Inspect terminal joints for signs of overheating and
oxidation. If found, clean affected component.
Lubrication
CAUTION
PRODUCT DAMAGE
Do not lubricate Auxiliary Switch, Signaling Switches,
Coils, Motor and secondary disconnects.
Failure to comply with these instructions may result in
product damage.
Ensure all metal-to-metal friction surfaces are kept
lubricated:
1. Remove old lubrication and dirt.
2. Apply Molecote 4700.
3. Wipe off excess lubrication.
TRIP UNIT TESTING
1. Test the circuit breaker operation against selected
protection settings (see Section 2) using a trip unit test
box (optional accessory).
2. Continuity check the mechanical trip alarm (if installed),
while test box tripping the trip unit.
3. Continuity check REF inter-trip (if installed).