A crusty suprise

[Arjun Saini]

So to start off I have obtained a ge BMY. I want to change the headwire and see if it will run. I know it does but for my own curiosity. I heard I have to pull the stator out. Since I’m inexperienced with these type of fans I was wondering if anyone local could help me. I want to thank Alex rushing and David Killnap for telling me about the headwire and replacing it. Problem is I live far away from them and I don’t think anyone is local. 

[Louis Luu]

I like crusty.

 

[Arjun Saini]

Me too. But the inside of the motor is a whole another level it’s dirty real dirty on the inside 

[Lane Shirey]

You have flat struts- it may have a centrifugal switch. There are 3 motor designs so pull the switch and post a pic. Also post pics of the area where the struts mount to the motor. Do you have a 2 or 3 wire headwire? 

[Arjun Saini]

3 headwire non centrifugal start 

[Arjun Saini]

Only pics I have l

[Arjun Saini]

For my own curiosity. Is there anyway I can safely hook this fan up to test it? I don’t know the wire combo 

[Dave McManaman]

2 hours ago, Arjun Saini said:

For my own curiosity. Is there anyway I can safely hook this fan up to test it? I don’t know the wire combo 

Do you have access to a multimeter?  I usually check continuity before doing a lot with a fan. That will help you know what you’re starting with. If you have a break, short, etc. I don’t put electricity into it till I know that it’s fairly safe to do so. Can fry pretty quick whereas might avoid that happening if you diagnose first. I hear you about being curious but slow is the way to go. 

[Alec Burns]

Here is the diagram I used for my BMY. It looks like yours is the same, with the nichrome wire wound into the windings, as long as you don't have a centrifugal switch on the rotor. In its current state the field coil switch having rust means the insulation is at least compromised there. I would recommend reading the stator leads with a multimeter and see if there are Ohms that match close to the diagram readings. Wouldn't recommend putting power to that motor as it is. Before you put power to that motor I would get correct Ohm readings, check for motor to body shorts (continuity when connected to stator lead and cast iron housing, indicates short), regardless of readings I would clean the stator (can be done with odorless mineral spirits and a soft brush, gently clean), dry, then soak with plenty of electrical insulating varnish (i use Sprayon EL600 clear, let it dry). Check the continuity again and ensure everything is good, then technically you could put power to that stator, because you have just refurbished an old stator!

 

To be safe, Steve Stephens had a brilliant technique of wiring wall power to two alligator leads, adding a lightbulb socket inline with one wire, and adding a lightbulb with similar wattage to the stator. Connect to the stator leads, plug in, and viola, if the stator is good the lightbulb will be dim, and if there is a short, the bulb would burn bright. Good luck and don't forget you're dealing with deadly electricity 👍

[Arjun Saini]

43 minutes ago, Dave McManaman said:

Do you have access to a multimeter?  I usually check continuity before doing a lot with a fan. That will help you know what you’re starting with. If you have a break, short, etc. I don’t put electricity into it till I know that it’s fairly safe to do so. Can fry pretty quick whereas might avoid that happening if you diagnose first. I hear you about being curious but slow is the way to go. 

Yes I have a multimeter but don’t know how to use it 

[Dave McManaman]

Alec does a great job of explaining what you’d be looking for in testing. Set your multimeter for ohms. Connect the leads to pairs of wire coming off the stator to see if you get good readings. A zero or very low read indicates there’s a break/weak point in the winding. If you get a zero or very low read, you could do a visual check to see if you find a broken wire. Can repair but if it’s buried in the winding or fried altogether, will need a rewind or replacement. In addition, like Alec described, check for a short go the fan body. One lead to a headwire, other to the motor housing. Should get zero as a reading. Anything more means you’ve got continuity indicative of a short to the housing and that’s a shock hazard. 

Edited January 28, 2022 by Dave McManaman

[Arjun Saini]

Ouch… I better be careful on this one 

[Ben Guegain]

I already tested this BMY and it works great. You’ll need to pull motor and rewire. 

 

 

[Rod Rogers]

2 hours ago, Dave McManaman said:

Alec does a great job of explaining what you’d be looking for in testing. Set your multimeter for ohms. Connect the leads to pairs of wire coming off the stator to see if you get good readings. A zero or very low read indicates there’s a break/weak point in the winding. If you get a zero or very low read, you could do a visual check to see if you find a broken wire. Can repair but if it’s buried in the winding or fried altogether, will need a rewind or replacement. In addition, like Alec described, check for a short go the fan body. One lead to a headwire, other to the motor housing. Should get zero as a reading. Anything more means you’ve got continuity indicative of a short to the housing and that’s a shock hazard. 

Your description of ohm readings is backwards! A low or zero reading indicates a short, a high or infinity reading indicates an open, as in a broken wire. The stator coils should read  around 100-400 ohms from wire to wire. From the wires to the motor case should read very high, even infinity.

 

~Sparky~

 

[Dave McManaman]

Rod, I thought that's what I said. If he gets a zero or low read when checking the head wires, there's a broken/weak wire in the windings. If when he's reading one of the head wires and across the motor case he gets anything other than zero, it's shorting to the housing/case.

[Rod Rogers]

Nope! If you have a broken wire in the stator, you will get a very high or infinite reading when reading across the wires. (Many ohms).

 

If you get zero ohms from the wires to the case, it's shorted to the case. (Very few ohms.)

 

Put your meter in the resistance function, then touch the meter leads together to create a short & see what your meter reads! It will be nearly zero!

 

~Sparky~

 

 

[Dave McManaman]

13 minutes ago, Rod Rogers said:

Nope! If you have a broken wire in the stator, you will get a very high or infinite reading when reading across the wires. (Many ohms).

 

If you get zero ohms from the wires to the case, it's shorted to the case. (Very few ohms.)

 

Put your meter in the resistance function, then touch the meter leads together to create a short & see what your meter reads! It will be nearly zero!

 

~Sparky~

 

 

Thanks for the correction

[Jim Kovar]

10 hours ago, Alec Burns said:

 

"Not Secure -- afcaforum.com"

Not that I mind,...
   but that prob'ly explains
      all the lingerie pop-up ads
         I'm always getting.  🤔

Edited January 29, 2022 by Jim Kovar

[Rod Rogers]

You'll notice that "Not Secure" is grayed out, indicating that's not the case.

 

Mine shows secure and verified by "Let's Encrtpt"

 

~Sparky~

[Arjun Saini]

Here’s a new one 

bet it’s insulation 

[Patrick Ray]

I've had a few like that. Sometimes lightly blowing it with compressed air gets the bulk out. Then some CRC electrical cleaner to finalize the cleaning. Then a good spray down with varnish and all will be good. This is all provided you are getting good readings across the stator. 

[Arjun Saini]

Does it matter the temperature outside when varnishing 

[Arjun Saini]

First I’m going to heat shrink the wires coming out of the switch. Then wire it up hopefully for a test 

[Arjun Saini]

Random ohm reading what does this mean?

 

 

[Patrick Ray]

On 1/31/2022 at 8:52 AM, Arjun Saini said:

Does it matter the temperature outside when varnishing 

In cold weather like we are having, I'll quickly run outside with the parts and varnish, spray everything down then come inside and place the stator on top of our water heater so the warmth will help it dry. Varnish dries quickly, but it's convenient since it's a couple feet away from my work bench.