Sounds like the speed control switch has been replaced recently, or one of the capacitors in the black brick in the switch housing has failed. Most modern fans use a double capacitor for medium and low. High is wired straight across the run capactor (which is usually 2 wire by itself, or all three capacitors may be in one big black brick)
The symptoms you describe suggest that the speed capacitor has failed. Typically they are 5+5MFD, or two in one case On Medium both 5MFD capacitors are activated, but on low only one is activated. The capacitors serve as a "choke" that limits the amount of current getting to the motor (not voltage, but amperage)
Find out the manufacturer of the fan and if it is Hunter, their number is 1-901-745-9222. Tell them the model# of your fan and they shall get you hooked up with a new cap.
Answers & Comments
Sounds like the speed control switch has been replaced recently, or one of the capacitors in the black brick in the switch housing has failed. Most modern fans use a double capacitor for medium and low. High is wired straight across the run capactor (which is usually 2 wire by itself, or all three capacitors may be in one big black brick)
The symptoms you describe suggest that the speed capacitor has failed. Typically they are 5+5MFD, or two in one case On Medium both 5MFD capacitors are activated, but on low only one is activated. The capacitors serve as a "choke" that limits the amount of current getting to the motor (not voltage, but amperage)
Find out the manufacturer of the fan and if it is Hunter, their number is 1-901-745-9222. Tell them the model# of your fan and they shall get you hooked up with a new cap.