What is a capacitor?

A capacitor in an air conditioner is a small cylinder, usually found in the outdoor condenser unit, that stores electrical charge and releases it in a short burst. That burst gives the compressor and the condenser fan motor enough push to start turning. Once the motors are running, the capacitor keeps them steady by smoothing out the power they draw.

Most residential split units in Yishun use a run capacitor, which stays in the circuit while the motor operates, and a start capacitor in some compressors. Both work the same basic way: they hold charge and feed it to the motor windings at the moment of start-up.

Why it matters: without a working capacitor, the compressor may hum without starting, start and stop repeatedly, or fail to start at all. A weak capacitor can also make the outdoor fan run slowly, which reduces airflow across the condenser coil. In a humid climate where units run for long hours, a capacitor that has swollen, leaked, or lost capacity is one of the more common reasons an outdoor unit stops cooling properly.

Because capacitors are sized to a specific motor, they are replaced with a matching rating rather than any part that fits. If you are looking for a technician who handles this kind of electrical fault, you can browse aircon repair providers in the directory.

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