The run capacitor of the refrigerator is an important component in its start-up relay. The run capacitor assists the refrigerator compressor, which should only run for a few minutes in any given hour. If it runs longer than that, the compressor can overheat or its motor can burn out.

A faulty compressor capacitor can cause the compressor to not start correctly, it can also cause overloading and trip breakers.

A capacitor can be tested with a multimeter (Farad) or visually, it can be noted if the capacitor is bulged or has burnt terminals.

Possible Solution

The μF sizes will vary with each refrigerator unit, however, in this example, we will use a 40μF (40 Micro Farad) capacitor, 250Volt and a Tolerance of ±10%. The specifications of each capacitor is usually printed on the capacitor.

Take note of the following on the capacitor:

1. The μF, in this case, will be 40μF.
2. Tolerance is indicated by a ± symbol and indicates that the capacitor will be approximately 5% more or less than 40μF. For example, 5% of 40 is 2, therefore the reading should be between 42μF and 38μF.
3. Voltage Rating. This indicates the voltage that the capacitor will operate. Which should be more than 250v. Ideally, a 380V capacitor should be used in order to handle voltage fluctuations.

Testing the capacitor

Disconnect and remove the capacitor from the compressor.

Warning! It is recommended you wear gloves or try not to touch the terminals of the capacitor as the capacitor may still have a charge which will give you an electric shock!

It is best to short out the capacitor before testing. To do this, short out the capacitor with a piece of wire. A small spark may appear.

You will need a multimeter with a capacitor tester and set it to μF.

Place the multimeter probes on the terminals to get a reading.

If your reading is 40μF, then the capacitor is ok. The reading must be within 5% (The Tolerance) of the reading.

If there is no reading at all, then the capacitor is faulty and will need to be replaced.