31
Instruction Book
IB182923EN September 2018 www.eaton.com
AMH-4.76-VR
+
VR-Series
+
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 Disconnect Contacts
• 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
Circuit Breaker Does Not Close
Control Circuit
(Close Coil does not pick up)
• Control Power (Fuse blown or switch off)
• Secondary Disconnect Contacts
• 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 Disconnect Contacts
• 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)
