I want to convert a 3spd box fan to operate on a pull chain switch. Help me figure out the switch wiring.
the shot below is the back of the OEM switch and the back of the pull chain switch for a ceiling fan. Both are numbered L-1-2-3.
Is it as easy as using the same numbers? I know on a ceiling fan the medium speed powers 2 points on the motor, but I can't find any info to tell if the box fan motor works the same way.
any helpful ideas? I mean, I hate to let the smoke out of a brand new $30 box fan.
Get a multimeter and probe the switch continuity.
So set the rotary switch to 1 and probe to see what outlet/s have continuity. Do the same for setting 2 and then setting 3. Then Repeat the process on the pull switch.
The wiring diagram for the pull switch suggests that it only has continuity to one outlet at a time. So long as the rotary does the same thing, it should be a straight swap.
Without being able to find a diagram for the rotary, I'll assume the 2 neutrals are just a simple pass thru/ join and neutral will be constant. With the cord unplugged and the neutral on the motor outlet side disconnected, Probe for continuity from neutral to neutral. Again, probe all other outlets to make sure the switch isn't doing something weird like double throw. If the neutral doesn't do anything weird and is just a basic joiner built into the switch you can join them with a connecter independent of the pull switch.
The continuity circuit in my meter is blown . I tried checking the voltage through the factory switch with the fan plugged in but the readings weren't helpful.
I wonder if I've got a coupon for a free harbor freight meter somewhere...
Ok, sorry, I found a better diagram. So you'll see there's some bridging between outlets going on depending what speed setting you're on.
Same rules apply to what I said above though. Test probe both switches and confirm they operate the same. If they do, you're good to go.
ultraclyde (Forum Supporter) said:
The continuity circuit in my meter is blown . I tried checking the voltage through the factory switch with the fan plugged in but the readings weren't helpful.
I wonder if I've got a coupon for a free harbor freight meter somewhere...
I literally made it through the first sentence and was thinking "QUICK! to Harbor Freight!"
In reply to ultraclyde (Forum Supporter) :
That makes it a little more tricky.... I guess you could GRM a poor man's circut tester if you need to know now.
Battery, globe, wire.... Globe will light up when you complete the circut. A bit of messing around, but it should get you an answer.
Yeah, I've either got a HF meter somewhere in the shop or can rig a test light. I was kind of hoping someone on here would be like "oh yeah, I've done that, it works great! Go for it!"
I mean, they're both mechanical 3 speed fan switches... It's probably 99% that they're going to be a straight swap. But without a diagram for both, or without probing and verifying they both definitely function the same, I can't just in good conscience say "she'll be right, swap em over". Sorry mate.
Hopefully someone else chimes in in the meantime.
Line, speed 1, 2, and 3... am I missing something? I think the N in your existing switch is just a straight pass through.
So, power from black goes to switch L, then out of 1/2/or 3, then back through the motor black line to the white N wire.
In reply to Robbie (Forum Supporter) :
Yeah, it seems pretty straight forward but the ceiling fan motor powers up 2 windings on the "2" setting and I'm not sure if the box fan does. I mean, it probably does, but if it's not designed that way I might burn out the motor. Not a huge deal, but it's a brand new fan, I hate to fry it. I agree the N is a pass through though.
No idea if it matters in your application, but the original switch appears to be rated at 8A @ 125V.
The rotary switches I found with the part number you are showing are listed at 6A @ 125V...
CJ (FS) said:
No idea if it matters in your application, but the original switch appears to be rated at 8A @ 125V.
The rotary switches I found with the part number you are showing are listed at 6A @ 125V...
Good catch, I hadn't noticed that, just assumed that a ceiling fan pulls more amps. Looks like my box fan draws a max of just less than an amp though, so should be ok.
Edit: I went back and looked at the photo above. The box fan switch says 3A@125 or 1.5A @250 volts, so should be good. the "3" is just a bad stamping.
Most AC variable speed motors use different windings to achieve the different speeds. The switches are pretty dumb. You should get zero ohms for each position you test. The switch simply sends full juice to winding #1, winding #2, or windings 1 and 2 together.
So, if my thinking is correct, it doesn't really matter how you hook it up. If you get it right, it will operate hi, medium, low, off. If you get it wrong, it might be hi, low, medium, off.
In reply to Curtis73 (Forum Supporter) :
That works for me. With a sequential pull chain I probably wouldn't know the difference anyway
