You may have noticed that your condenser start capacitor may be worn out. In a new system the start capacitor has a primary winding and a secondary winding. The primary winding is made up of copper-clad fiber and the secondary winding is made up of many strands of copper tape wound around a core. The primary winding is wound tightly enough so that it creates a very tight seal on the capacitor’s coil, and the secondary winding is wound loosely enough so that the heat from the capacitor’s plates cools off the primary. The primary and secondary windings must be equal in length before the capacitor starts to operate.
As the system ages the primary and secondary windings wear out. This causes a fluctuation in the current that is the most common problem. If you find that your capacitor is operating slowly or doesn’t start up at all, you may need to replace the insulation on the outside of the capacitor. If the insulation has become worn, it makes the actual tube bigger, and this causes the capacitor to operate with less voltage. If you need to replace the cap with another one, check for small burrs on the insulation.
To inspect the insulation you can use a Q-tip and cotton swab. The easiest way to do this is to put the Q-tip and cotton swab into the capacitor so that you can see the insulation. If the burrs are small, you can use your fingers to feel them, but if they are large, the cotton swab works just as well. Be careful not to put too much pressure on the inside of the capacitor because this can cause some damage.