A motor capacitor can form part of the mechanism for a number of different electrical items, including an air conditioning unit. However, there are occasions when the component can fail, which will require you to know what signs to look for that this has occurred.
1 – Speed In the event that you are suddenly unable to achieve a certain level of speed after switching on an air conditioner, you may find that the motor capacitor is at fault. The capacitor will often provide the appliance with a boost facility, which will fail if it is faulty.
2 – Failure A motor capacitor may be required in the event that the air conditioner fails to work at all. The capacitor is the component through which power is drawn, accordingly, if the fans fail to rotate at all or only works intermittently, the capacitor may be to blame. If the motor stops working, the capacitor may be the cause.
3 – Noise In view of the fact that a motor capacitor plays a role in making the motor run, you may find that a fault with it causes a change to the sound it makes. If the air conditioner rattles or sounds different than it previously did, the capacitor may be defective.
Read more: http://www.doityourself.com/stry/3-ways-to-tell-if-you-need-a-new-motor-capacitor#ixzz1ZAn3jsZa