What happens
Internal dielectric damage or a terminal fault creates an abnormal current path.
Typical symptoms
Protective trip, ruptured case, leaking material or abnormal motor behavior.
Checks that distinguish this cause
Stop operation and isolate before approaching damaged parts. Confirm circuit integrity with the capacitor safely discharged and separated from wiring.
What can look similar
A grounded motor or chafed harness can trigger the same protection. Never assume a bulged capacitor is the only fault.
Repair direction
Replace the damaged approved component and evaluate the connected motor and supply.
Verify the repair
Verify insulation and wiring integrity, then normal start and running behavior.
Equipment-specific limits
Use the OEM capacitance, tolerance, voltage rating and terminal arrangement. ECM and inverter motors have different electronics; this procedure is not a universal motor test.
Practice this diagnosis
This cause is a reference topic; it does not yet have a dedicated simulated call. Browse the practice board.
References and applicability
Original HVACSim explanations with manufacturer and instrument-maker references for further reading. These resources support the subject; their model-specific examples are not specifications for every system.
- Fluke: How to measure capacitancePower isolation, discharge and capacitance measurement.
Editorial review: 2026-09-29. Verify the current manual for the installed model.