I recently installed three ceiling fans in a warehouse space. Of the
three units, one of them failed shortly after installation (the
installer didn't know what he was doing and blew it up), and someone
else replaced the wall controller with another unit. The replacement
wall controller had a 4 position slider (Off / Low / Med / Hi* ) like
the original, but I don't think it's exactly the same internally
because in the "Off" position, the fan is still moving at a very slow
rate (2-4 cycles per minute). Plus the slider goes the wrong way, but
that's just cosmetic.
The fans have a single hot wire going to them (and a neutral coming
back), so there's no fancy tach/feedback stuff going on here, just
supply power manipulation.
I'd like to replace the failed controller with the exact same model by
the same mfg (Rhine Electronic, Model UC9020, apparently Taiwanese) but
their website is nonfunctional and I can't even figure out who their
distributor in the US might be. So now I'm looking into at least
getting a controller that works the same.
I took the failed controller apart and it is built around two large
capacitors, labeled 8.0 uF and 12.0 uF (actually they're rated "uFJ",
whatever that means). There are a few resistors, the 4 position slider
switch and then that's it. I assume that this serves to cut the AC
waveform or drop the voltage somehow.
If I go buy a replacement fan controller, what should I be looking for?
Are there different types? (e.g. voltage limiting? current limiting?)
All the failed controller label says is the current rating (1.5A).
Obviously it is possible to get the wrong kind, because that's what
I've got now.
Obviously, the original fan controller switched the capacitors around to change
speed. Typical for a split phase motor. And I don't think you can control a
split phase motor's speed with just two wires... there has to be a hot and
neutral, but also a third wire that connects to the appropriate capacitor.
Many fans have the capacitor(s) inside the motor housing (designed to work from
a pull switch hanging from the motor). Possibly is your fan of that
construction? If so, a controller having the capacitors won't work.
I'd be very suspicious of the wiring to the fan. That is probably why the fan
doesn't run with the original controller.
The replacement controller that you have is probably a "dimmer" type controller,
and will not work with your fan.
In my opinion, your first move would be to make sure that the wiring to the fan
is correct. Unless the improper installation ruined the switch, it's unlikely
that the capacitors are damaged. Most likely thing is that the improper
installation ruined the fan motor by burning out the split phase winding.
Prepare to buy a new fan or replacement motor.
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
In the case of a ceiling fan, you can control it using just two wires.
How? Using a choke (reactance) with several taps. That΄s the way it
was done until very recently. The controller had 5 speeds, and the
highest speed just bypassed the choke.
Question: what do I need to read to at least try to
understand what you all are talking about -- split-phase
motors, need for capacitor (or coil, as above?), etc?
(I used to know *some* EE stuff, phase, etc, but that
was a *long* time ago.)
Fan speeds are controlled by switching capacitors of different sizes in
series with the supply line. If using a fan control other than the internal
pull chain control, one should leave the fan mounted one on "high".
Thanks for the replies so far. It definitely is just a two-wire
control (hot + neutral) and is properly wired. The other two
fan/controller pairs work just fine, it's just this one controller that
died. And the fan doesn't seem happy with the controller that someone
installed as a replacement. I've already scolding him for doing my job
One of the replies said:
That looks like the controller I have -- two big caps, a few resistors,
and a slider switch; NO ICs. Is this pretty much the only way to
control a fan with one hot wire? If so then I'll just look for fan
controllers that show only one wire going to the fan (and the neutral
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