i have a d903 electric motor on my ac unit and it wont start on its own. if you start it by hand it runs but i?
I would check the bearings - clean and oil all bearings. Good Luck
Edate Troll is a little fuzzy on how capacitors work, but is on the right track. The two most likely causes of a motor unable to start on its own is a failed capacitor or failing bearings. These motors typically have sealed bearings, and cannot be easily lubricated. With power off, grab the blade and give it a spin. If it spins freely, try to wiggle the motor shaft side to side. If you get any play out of it, the bearings are failing. When bearings are going out, the motor usually makes a bit of a hum or grumble as it tries to start. My first instinct would be to replace the capacitor.
The capacitor for starting the motor may be bad. Capacitors store electricity, in this case they discharge when the motor is turned on to give it an extra boost of electricity. Some motors also have an internal start winding and if this winding burns out then the motor won't start on its own. I recommend that you have a tech look at it, capacitors still carry a lethal amount of current even when everything is turned off and the electricity supply disconnected.
