Centrifugal Vacuum Fan

The earth leakage circuit breaker tripped twice today. It is just conceivable that something was wrong with the oil vapour sucker. The miniature circuit breaker was fine though so it wasn't a short circuit but more precisely an electrical leakage through earth. I took out my multimeter and turned the switch to test for resistance. Then, I touched one probe on the metal casing and another probe on the live wire. The meter measured 900k ohm.

There are two centrifugal fans in the oil vapour vacuum, I disconnected one fan and analyzed the resistance between the metallic casing and live wire before I realised there is no electrical leakage in that fan. The damage fan was removed from the circuit, leaving one working fan to suck the oil vapour and the gap of the other fan was shut. The oil vapour vacuum is ready to work again.

Did you realised that this fan uses a transformer to make it moved? The adapter that you used to charge your handphone has the same working principle as the AC fan's motor. AC motors are brushless since the coiling is on the side rather than the rotor (for DC), therefore it is more reliable.

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