30
Instruction Book
IB182023EN March 2016 www.eaton.com
AMH-4.76-VR
Replacement Circuit Breaker
Tablt 6.3. Troubltshooting Chart
SYMPTOM
INSPECTION AREA
PROBABLE DEFECTS
FAILS TO CLOSE
Closing Springs Not Charged
Control Circuit
• Control Power (Fuse Blown Or Switch Off)
• Secondary Disconnects
• Motor Cut-off Switch (Poor Or Burned Contacts. Lever Not Operational.)
• Terminals And Connectors (Poor Or Burned Contacts)
• Motor (Brushes Worn Or Commutator Segment Open)
Mechanism
• Pawls (Slipping Or Broken)
• Ratchet Wheel (Teeth Worn Or Broken)
• Cam Shaft Assembly (Sluggish Or Jammed)
• Oscillator (Reset Spring Off Or Broken)
Closing Springs Not Charged
Breaker Does Not Close
Control Circuit
(Close Coil Does Not Pick Up)
• Control Power (Fuse blown or switch off)
• Secondary Disconnects
• Anti Pump Relay (Y Relay N.C. Contact Open Or Burned Or Relay Picks Up)
• Close Coil (Open Or Burned)
• Latch Check Switch (Contact Open - Bad Switch Or Trip Bar Not Reset)
• Auxiliary Switch (B Contact Open Or Burned)
• Motor Cut-Off (Contacts Open Or Burned)
• Trip Coil Assembly (Clapper Fails To Reset)
Closing Sound But No Close
• Pole Shaft (Not Open Fully)
• Trip Latch Reset Spring (Damaged Or Missing)
• Trip Bar-D Shaft (Fail To Remain Reset)
• Trip Latch-Hatchet (Fails To Remain Reset)
• Trip Floor Tripper (Fails To Remain Reset)
• Close Latch (Binding)
• Close Latch Roller (Binding)
• Trip Circuit Energized
UNDESIRABLY CLOSES
Control Circuit
• Close Circuit (CS/C Getting shorted)
Mechanism
• Close Release Latch (Fails To Reset)
• Close Floor Tripper (Fails To Reset)
FAILS TO CLOSE
No Trip Sound
Control Circuit
• Control Power (Fuse Blown Or Switch Off)
• Secondary Disconnects
• Auxiliary Switch (A Contact Not Making Poor Or Burned)
• Trip Coil (Burned Or Open)
• Terminals And Connections (Poor Or Burned Or Open)
• Trip Clapper (Jammed)
Trip Mechanism
Trip Sound But No Trip
Trip Mechanism
• Trip Bar, Trip Latch (Jammed)
• Pole Shaft (Jammed)
• Operating Rod Assembly (Broken Or Pins Out)
Vacuum Interrupter (One Or More Welded)
UNDESIRABLY TRIPS
Control Circuit
• Control Power (CS/T Switch, remains made)
Mechanism
• Trip Coil Clapper (Not Resetting)
• Trip Bar or Trip Latch (Poor Engagement Of Mating Or Worm Surfaces)
• Trip Bar Reset Sprint (Loss Of Torque)
