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Repair and support for ceiling-mounted bladed fans.

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Trouble finding celing fan capacitor replacement

I have a ceiling fan that will only run on one speed. After some research and testing, I’m fairly certain I need to replace the capacitor. I’m just having a hard time finding a matching one.

I know just enough about electrical to ask questions before it gets dangerous, so sorry for any incorrect terminology…

The markings on the old capacitor say 350v and 4uf. I know the replacement can be higher than 350v if needed, but should be exactly 4uf.

The problem I’m running into is that the old one has 3 wires (1 red, 2 white), and all of the 3-wire capacitors I’ve found so far have 3 different colored wires with 2 different uf values.

I’m assuming the red wire is the input or hot wire and the 2 white wires are the output and share the same 4uf rating. If so, can I just get a 2-wire 350v 4uf capacitor and connect the single output wire to both of the fan’s white connections? If not, is there somewhere you recommend for finding a 3-wire 350v 4uf capacitor?

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Hi @jargs ,

What is the make and model number of the fan?

Post an image of the capacitor in question showing the markings and the wiring etc.

Here's how to do this on iFixit Voeg afbeeldingen toe aan een bestaande vraag.

Are the two white wires joined together or even the terminals they're connected to, are they joined together? It may be that they are just in multiple connection for the supply in the fan.

Disconnect the wires from the capacitor and then use an Ohmmeter to test between the capacitor terminals where the two white wires were connected and check if they are short circuit.

Also some DMMs (digital multimeter) have a capacitance test function which you may be able to use to test the 4uF capacitor (if the meter’s capacitance test range is this high). Discharge the capacitor first before testing i.e. short out the red wire terminal to the white wire terminal (or both?) for a few seconds.

The 4uF is necessary to get the correct current (i.e. therefore speed) for the fan.

Also don’t assume that the red is the hot wire. In some places the white wire is the active wire in electrical appliance wiring. ;-)

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Agreed. Please post a pic of the old capacitor and we can help you source a new one. Just went through this with one of my ceiling fans as well.


Thanks for the responses... unfortunately our weather heated up, so I had to put the fan back together just so we'd have something to move the air. It's at the top of a vaulted ceiling, so it may be a little while before I am able to take it all down again to get a photo. I'll update this post when I do.


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Celing fan very old and the fan is sed hoto repeir

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Ceiling fan speed is not controlled by capacitors but by field windings. (The non-spinning part is the the stator. The 'spinning' part is the rotor or armature).

The speed selector switch merely adds more field windings to the stator windings thus increases the rotor speed. You can measure this on multimeter. Each speed setting will change slightly on a sensitive OHM scale as you change speeds. (Of course with everything unplugged and probes directly connected to the fan's input wires).

The 3-wire capacitor is actually two capacitors in one internally wired with both caps using a common lead. One cap acts as the 'starting' cap, the other as the 'running' cap. There ought to be two values printed on this double cap. (Possibly you can't see both values because they may have faded over the years due to heat). These are hi voltage (X2) capacitors and have to cater for the maximum voltage swing encountered in AC supplies (about 312V peak-to-peak for a 110V AC mains supply).

Therefore if your fan runs at only one speed, suspect the speed selector switch or most likely an open field winding(s). Do the multimeter test to determine.

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J Richmond zal eeuwig dankbaar zijn.

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