R-Pro › Field cases › Refrigeration systems
Magnetic Contactor Failure
Likely causes
Contactor coil open circuit
Check: Confirm control voltage is applied to coil terminals
What to do: Confirm control voltage is applied to coil terminals → Measure coil resistance (tens to hundreds of Ω; open = infinite) → Visually inspect main contacts for carbonization or welding → Replace with same spec (coil voltage, current rating) → Perform manual test after replacement
Main contacts seized or carbonized
Check: Measure coil resistance (tens to hundreds of Ω; open = infinite)
What to do: Measure coil resistance (tens to hundreds of Ω; open = infinite) → Visually inspect main contacts for carbonization or welding → Replace with same spec (coil voltage, current rating) → Perform manual test after replacement
Coil voltage rating mismatch
Check: Visually inspect main contacts for carbonization or welding
What to do: Visually inspect main contacts for carbonization or welding → Replace with same spec (coil voltage, current rating) → Perform manual test after replacement
Control signal is normal but the contactor is not energizing. Coil or contact fault — replace the contactor. Always disconnect power before inspecting or replacing main contacts.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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