Ceiling Fan Capacitor Woes

When we moved, the house we moved into did not have forced air circulation or heating, so in order to circulate the warm air from the single wall heater into the various rooms, we installed 4 ceiling fans about 8 years ago, one in each room, and one in the central hallway, which is closest to the wall heater. One of the issues we’ve encountered over the years with these 3-speed reversible ceiling fans is the fact they have speed-control capacitors that occasionally burn out. So far, it has always been one of the two in control of the lowest speed circuit, which uses the least power when it’s working properly, and it’s also the speed that the fan is operating on most of the time it’s on. The factory module is an integrated three-in-one unit, molded into a single, insulated plastic housing, with five wires. These fans are now about 7- or 8-years old.

While on our monthly grocery shopping trip, we stopped by the store where we purchased the fans. They either no longer carried these replacement capacitors, or never carried them in the first place.

The home center, sometimes referred to as a mega-store, did have wall-mount speed controls, and had I desired to cut a hole in the wall, install an electrical box, the necessary wiring to the fan, patch the drywall and paint, as well as spend the additional time to accomplish all of that, then perhaps those types of speed controls could be retrofitted into the existing system, but I just wanted a replacement module for the burned out capacitor so the repair was quick and simple, nor involved replacing the rest of the perfectly fine ceiling fan.

At the mega-store, after looking for replacements on the shelf and not being able to locate them, I then spoke to the employee in the fan department, who said, “No, we don’t carry them,” but added that he’d been trying to get management to stock them and hadn’t had any luck.

I went to the customer service desk, and looked through their supply book for some period of time, checking multiple cross-references in its index. Nope, there were no in-the-fan-housing capacitor modules to be found.

Later that evening after we got back home and unpacked the groceries, I searched the Internet, and found several online suppliers.

1. Replacement ceiling fan capacitors supplier site 1.

2. Replacement ceiling fan capacitors supplier site 2.

In studying those two sites above, it is apparent from the latter one that even though the modules are rated by the two, three, or four capacitors they contain, the schematics and internal wiring also have several variations. This would affect installation of a replacement. Since the type we need has two wires internally connected to one side of all three capacitors according to the on-the-module schematic, some of the four-wire type that don’t appear to match should work provided I wire them into the rest of the fan’s wiring in such a way to simulate that internal connection.

It appears that a number of differently rated modules could be installed. The exact same values as the failed unit are probably best provided those values are printed on the outside of the bad module. In our case they were: 5-wire, 4uf + 4uf + 5uf; the second fan is 4uf + 5uf + 5uf; “uf” means micro farad, a value of capacitance. No module replacements seem to match those values exactly in 5-wire, and it’s cautioned that the capacitance value can only vary by +/- 1uf. The repair question morphs again, complicating matters: do we want a slightly slower fan speed, or slightly faster, and which farad value, either an increase or a decrease, achieves each?

For a slightly slower speed it appears we’ll need a lower capacitance value: for a higher speed, a higher capacitance value. Apparently, a shorted or solid wire approaches infinite capacitance (MS word doc).

This is confirmed by the schematic logic in the links below. Perhaps it would be better to just replace the single one that has blown:

1. Single ceiling fan capacitors supplier site 3.

This is an interesting repair option, and in our fan’s case of a factory three-in-one module, it would likely and initially require installation of three single capacitors due to the fan-case space limitation of keeping the old module in addition to the replacement: the bad one can’t singly be removed. Unfortunately, at the time of this writing, these “single capacitors” may not have the correct rating, their catalog is using an “m” (milli) instead of a “u” (micro). This is possibly a typo related to the computer age’s typical use of ASCII, the actual, old-fashioned character for micro is “µ”.

Another question arises: is there enough room in the fan’s case, or, what physical size are these single capacitors? One attraction of these is that once the three-in-one module is replaced with three single ones, and properly wired into the rest of the fan, should any ever blow again in the future, only the single blown ones will require replacement. One downside of this is that they are not available in fractional microfarad values, should one of those be desired for any reason. Another downside is that the supplier only has values of 1-5 “m”fd, no 6 or 7, so this will not work for one of the fans which I want to very slightly increase the hi speed, and increase the low and medium speed, unless an extra one is added in parallel: then there would be additional housing-space requirements.

For those who may need additional ceiling-fan repair instruction:

1. General ceiling fan repair with photos, repair information, and wiring schematic.

2. Schematic diagram of reversible 3-speed ceiling-fans.

While I won’t be installing a variable speed controller, it is nice to know one could be built from scratch, if desired:

1. Variable speed ceiling fan control.

Some online sources claim the variable type of speed controller sometimes cause humming or buzzing while the fan is in operation.

Perhaps it goes without saying, but I spent several hours online learning more about ceiling fan capacitors than I ever wanted to know! I’ve actually created a spreadsheet and, assuming the generic schematic (scroll down, two different ones on page) that may match our fan, attempted to mathematically simulate the capacitance difference between the two motor inductance coils, since there are so many possible capacitance value combinations possible that feed these coils.

While it’s always nice to learn something new, if you have the time, these blown speed-control modules should have been a simple-to-replace item, but it’s become slightly more complicated than simple!

This has become a two-part topic, the next post is a continuation: Ceiling Fan Capacitor Solutions.

I’m sure there are a lot of other sources of ceiling-fan capacitors, and if I didn’t find yours: so sorry.

General electronic references:
Capacitors in series and parallel.
Schematic Symbols site 1.
Schematic Symbols site 2.
Capacitors.

Electronic Abbreviations site 1.
Electronic Abbreviations site 2.

Capacitor suppliers not listed above:
Ceiling Fan Capacitor supplier site 4.

Ceiling fan capacitor manufacturer information:
PDF - NTE ceiling fan capacitors