I recently installed 3 identical ceiling fans. I wired the fans to a 4"x4" junction box with one power supply. (The fans are all very low wattage, so circuit overload should not be a problem) I twisted all of the black wires together, white wires together and ground wires together with properly sized wire nuts. Two of the fans work fine, but the motor gets very hot one one of the fans. I have returned the fan to the store 3 times and still have the same problem. Any idea what the problem is?

 

Are any of the fans connected to wall switches, or are all of them permanently hot? Is there anything in the 4x4 junction box except four black/white/bare cables, one bringing in power and three taking power to the three fans? Where exactly does the cable bringing power in come from?

 

None of the fans have wall switches...they are controlled by the pull chain. The junction box contains only black, white and bare wires. The power to this junction box comes from an existing junction box that feeds a few wall outlets. I appreciate your help.

 

Well, that's a mystery.

Most people wouldn't even notice if the fan motor got hot or not. I don't know how hot it is getting, but maybe it's not a problem.

What's different about this room? Is the room smaller? Is the fan closer to the ceiling? Does the room have a west or south facing window? Is the ceiling sloped? Blades longer or shorter?

You might measure the voltage at each fan, but that is only a meaningful test if you can measure it with the fans running.

 

Would an open neutral cause the motor to get hot? Even though I don't think I have an open neutral, someone told me that might be the problem.

I am on fan # 4 and about to give up!

 

An open neutral would only cause it to get hot if you had a multiwire circuit, which apparently you do not.

A loose connection can always cause heat. But this heat would be where the connection is made, which is at least six inches from your motor, and it seems unlikely for significant heat to transfer that far. If the connection had gotten that hot, you'd probably see melted insulation when you replaced the fan.

Either low or high voltage can also cause a motor to overheat. But since all the fans are connected to the same feed, it's hard to understand why just this one fan would be getting low voltage.

 

I just installed fan number 7 and all seems to be OK. The first 6 were either too noisy or got too hot. I tried 3 Harbor Breeze (Lowes brand), 1 Hampton Bay (Home Depot brand) and 3 Hunter. The last Hunter is the one that is OK. I am going to assume that my wiring is correct and the fans that got hot were somehow defective.

 

That sounds like a lot of bad fans.... not questioning your wiring, but I've installed 3 Hunter fans in the last 2 weeks and they all work great, every one of them. I have mine wired a bit different: Supply from panel -> Junction box -> Splits off to 2 wall switches for each fan (1 for light and 1 for fan motor). All of them work great without a hitch and no over heating problems to speak of. Also, the circuit is all 12 gauge wiring.

 

That does sound like a lot of bad fans!!! The symptoms described are symptoms of low voltage. Perhaps there's a series fault situation? The connection in the JB? There's four conductors connected - are you sure they're all really tight? Just using the right sized wire-nut doesn't guarantee that. Or a bad length of cable or a clamp too tight that has created a series fault - (broken, but touching conductor)... Sounds more to me like you got lucky with a fan that behaved to your satisfaction with the lower voltage.... I'd check for heating in both JB's and along the cable just to be sure. Not sure I could sleep after 6 "bad" fans..... There are also ways to check the voltage at a running ceiling fan. One would be to remove the light fixture (or cap) and check the voltage available to the lights. Just be sure to use clip on test leads or keep your head down!!!!

 

What type of tester do I need to check for low voltage?

Only 3 of the 7 fans actually got too hot. The others were returned for various reasons, such as too loud, bent motor armature.

 

A voltmeter, or a multimeter. But as I said, to be an accurate check, you have to check the voltage while the fan is running. That can be a bit hard to do with the fan blades hitting you in the chest.

 

Can I test for low voltage using the unused leads for the light like rodek01 suggested?