Alfen
Acoustic Noise from Contactor or Magnetic Components
Charger emits a loud humming or buzzing noise during charging.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Aging or loose contactor coil, Vibrating transformer or inductor in power supply, Loose mounting screws on contactor or DIN rail, Slight phase imbalance causing magnetostriction noise
How to Fix / Troubleshooting
Safety first: Isolate power before tightening or touching internal components.
- Step 1 – Identify source: With the cover removed (and power OFF), locate the component that vibrates when charging (contactor, transformer).
- Step 2 – Tighten mounting: Ensure the contactor and any transformers are firmly secured to the backplate or DIN rail.
- Step 3 – Check coil voltage (technician): A technician can verify that the contactor coil is receiving the correct control voltage; undervoltage can increase buzzing.
- Step 4 – Replace noisy component: If noise is excessive or accompanied by heating, replace the contactor or power supply module.
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Repair Difficulty
Medium
3/5
Required Part
Main Power Contactor Assembly
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