# Electronics for Dummy (me)



## Doc Doom (Aug 28, 2008)

As I posted, I'm trying to modify a ceiling fan for an Axworthy Ghost. I want to mount a large drive pully directly to the motor so need to remove the light kit housing and jumble of wires, switches and other unidentified parts (capacitor, I think) inside the metal cup that the lamp kits attaches to. I'm making the drive pulley from two metal serviing trays. I can cut a reasonable sized hole in the middle of the plates to accomodate some of the wires. I've spent hours online researcing and have found that the small solid box-like part is most likely a capacitor that somehow welps helps the motor start faster. What I can't seem to find out is will it still work without the capacitor? I'd really like to get it out of the way. I only need one speed in one direction. Although I'll admit to being a civil engineer, I'll also admit to not being able to understand wiring schematics anymore. Can anybody smart enough to understand this stuff help me out? I'm about ready to just start cutting wires to see what happens. 
Thanks


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## Phil (Sep 2, 2007)

The "smart enough" qualifier rules me out, but here goes until somebody smart shows up. I attempted to use a ceiling fan motor for a prop once, but abandoned it due to insufficient torque. I did find out that the cap is kind of a "jump start" to get things rolling from a stalled position. It does need to be present unless you want to push start the fan. The other switches can be jumped out of the circuit since you only need one direction and one speed. I love me a wiper motor.


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## BillyC333 (Mar 13, 2010)

The black box is most likely a capacitor, if removed you may loose some speed settings, need to hand start, or worst case it will not spin by itself at all. You may want to try to relocate it with some extra wire. Be careful though some capacitors store a lot of energy and can pack a punch. Not really sure about the flavor that gets added to ceiling fans.


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## Doc Doom (Aug 28, 2008)

Bill & Phil,
Thanks for the advice. Looks like I'll have to relocate the switches and the capacitor to the top of the assembly, that is after I learn how to discharge the capacitor.


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## corey872 (Jan 10, 2010)

I probably don't qualify for the "knowledgeable" part either - but if there is a capacitor, you will need to keep it - at least wired up for the speed you want to use. This page gives a little description and some schematics:

http://www.electrical-forensics.com/CeilingFans/CeilingFans.html

But in short, the box capacitor you mention likely has two individual caps inside. The fan uses one or the other, or both combined to make the 3 speeds run. Without it, the fan is likely to run very slowly and with little or no torque - well, even less than a ceiling fan would have normally.


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## BillyC333 (Mar 13, 2010)

There are tools to discharge capacitors, they work by applying a big resistor between the two contacts. You can always use the NON-SAFE, Non-recommended way.. well insulated screwdriver across the cap  and you will hear it snap.. haha


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## Dead Things (Apr 4, 2009)

BillyC333 said:


> You can always use the NON-SAFE, Non-recommended way.. well insulated screwdriver across the cap  and you will hear it snap.. haha


Ya, that one will put hair on the balls of your feet... or remove it lol
Good luck with the Axworthy by the way. I have one and it is a hit. It can also be a pain in the a**.


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## hedg12 (Jul 6, 2008)

Phil said:


> I attempted to use a ceiling fan motor for a prop once, but abandoned it due to insufficient torque.


I'd have to go with Phil on this one. Ceiling fan motors are very low powered for safety reasons - the manufacturers wouldn't want any accidental decapitations. You'd have to have a pretty smooth running cable assembly for the ghost to run.

That being said, everyone else's responses are right - you'll have to leave the cap in the circuit, but you can bypass the switches with no problems.


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## corey872 (Jan 10, 2010)

Re - cap discharge: Assuming the cap doesn't have a small internal resistor (which is pretty rare in today's safety conscious / lawsuit happy times) - it is already in series with the motor windings. So - in the unlikely event the cap is still holding a charge - if you twist your three input wires together and flick the three way switch through the speeds a couple of times, you would discharge the cap harmlessly through the motor windings.


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## Doc Doom (Aug 28, 2008)

corey872 said:


> - if you twist your three input wires together and flick the three way switch through the speeds a couple of times, you would discharge the cap harmlessly through the motor windings.


Here's a pic of the of the capacitor in question. Can you tell me which the three input wires are? My money is on the three coming from the switch to the capacitor, brown, purple and gray.
thanks


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## corey872 (Jan 10, 2010)

Sorry, I should have been more clear - I meant the three input wires of the ceiling fan - should be black, white and copper, though 'electrically' if you just twist the black and white together and turn the fan on, you create a circuit which would discharge the cap.

If you were to do it at the cap level, then going by your picture, touching the gray wire to the red, brown, and purple in turn would insure the cap is discharged. If you want to do it the 'proper' way, then touching the wires across a ~10K - 100K ohm resistor would eliminate the small 'spark' you might get by just touching the bare wires.

But in reality if the fan hasn't been powered for a week or so, the cap is most likely self discharged, though it never hurts to be careful.


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