Hot retrostat

Tadams32

New Member
Dec 28, 2020
21
North Carolina
I have had issues with the wiring of my black bart 2 insert. I do have the fan running now after trial and error. The retrostat is getting hot to the touch. I thought the retrostat could be used to control fan speed. But it's the same when I rotate the dial. I'm hoping this is a wiring issue. I had checked the retrostat and it shows the resistance changed as I rotate the dial.
Thanks
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,936
South Puget Sound, WA
What rheostat is being used specifically? Is it a fan motor speed controller?
 

Tadams32

New Member
Dec 28, 2020
21
North Carolina
It is to regulate the fan speed. I'm not certain of the brand, it is the one that is on the stove. By checking with a meter it appears to be working. My concern is the proper wiring. I purchased a new wiring harness but the old wires were not connected. Looking at the only wiring diagram I can find for the stove is incorrect. It shows 2 black wires coming from the power cord.
Thanks for your assistance
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,936
South Puget Sound, WA
Normally this is a simple series circuit. Is the speed control the original one for the stove? Can you post the schematic you found?
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,936
South Puget Sound, WA
What model Black Bart is this?

I'm sorry but it is hard to know we are talking about the same thing without seeing what you are seeing. Do you have a cellphone that you could take a picture of the schematic and post it?

I found this drawing, but have no idea if it applies to your stove model.
Screen Shot 2020-12-29 at 11.06.17 AM.png
 

Tadams32

New Member
Dec 28, 2020
21
North Carolina
Black bart 2. I am trying to send a picture of how it is wired but on this site I'm not certain how. I can tell you the thermostat is new. It has 2 wires a black one coming from the motor.
The retrostat had 2 wires. A red one from the motor and a white wire from the power cord.and a white from the power cord. The black wire goes to the
The power cord has a black, white and green wire. The green is a ground..
That has a black wire to the capacitor. A red wire from the motor to the capacitor. A white wire from the motor and a black wire from a black wire from the power cord.
Thanks for helping me with this.
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,936
South Puget Sound, WA
Interesting. I see that picture diagram in the Black Bart 3200 manual. Is there no manual/auto switch on your stove? Just the rheostat switch?
 

begreen

Mooderator
Staff member
Nov 18, 2005
85,936
South Puget Sound, WA
I am confused why in the manual there are two quite different wiring diagrams, but I see what you are using now. This is figure 10 on page 7 of the Black Bart 3200 manual. And yes, you are right, the person doing that drawing did a poor job of noting wire color or the power cable coming in to the blower box was different and lacked a white wire. If it was consistent with the Black Bart 1 wiring diagram then the white wire from the power cable would go to the capacitor and the black wire would go to the rheostat/switch. The changing of wire color code shown in the drawing is seriously inconsistent.

Basically, the incoming black (hot) leg should connect in series the rheostat/switch, then the snap switch, then the hot (black) leg of the motor. The white (neutral) should go to the capacitor, and the capacitor connects to the other leg of the fan motor. Does that make sense?

Be safe and only check when the unit is unplugged and remember that the capacitor stores a charge and can still shock even when all is unplugged.
 
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Tadams32

New Member
Dec 28, 2020
21
North Carolina
Thank you so much. I'll give it a shot. Crazy, I can restore a classic car or build any type furniture my wife would want, but this thing is being a pain.
 

rwhite

Minister of Fire
Nov 8, 2011
1,767
North Central Idaho
Hopefully you got it figured out. If not do you have 3 wires coming off the motor ? Its possible you have your start and run windings wired backwards and its creating high resistance. The wiring diagrams (other than colors) look the same. It appears that begreens diagram is for a dual fan set up. I dont believe any of it is polarized so the motor windings are the only thing to make sure are they are going to the right place.
 
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Tadams32

New Member
Dec 28, 2020
21
North Carolina
I'm going to check it out today. There are 3 wires coming off the motor. That is correct. I had the fan running yesterday but as said the retrostat was getting hot and the fan only ran at one speed. Thanks for your assistance
 

rwhite

Minister of Fire
Nov 8, 2011
1,767
North Central Idaho
There could be a few or combination of issues.
1. Windings are backwards. Check resistance between red/wh and Blk/wh. There should be continuity but there should also be a higher resistance on one set than the other. The one with the highest resistance would be the start windings. Those go to the capacitor. Start capacitor are not polarized so they can go to either side but the power cord must be on the same side as the wire (probably white one) which is common between the two.
2. Another issue or combination of issues is that the clutch may not be kicking out the start windings. Induction motors have a centrifugal clutch that kicks out once up to speed and takes the start windings out of the circuit. If that is not working it would create very high resistance trying to run both sets of windings at the same time. You can take the motor cover off and make sure the clutch moves freely or you can check the resistance of the start winding wires once the motor is up to speed. Should have continuity at a stop and open circuit when running.
3. The other problem may be the fan control. Its probably not a true rheostat but most likely a fan control. They do slowly wear out and create high resistance.
 

Tadams32

New Member
Dec 28, 2020
21
North Carolina
Thanks for the reply. The retrostat seems to be good. Checked using a multi meter. As dial is rotated the numbers change. The motor runs. But seems to be at a low speed with no adjustability.
 

rwhite

Minister of Fire
Nov 8, 2011
1,767
North Central Idaho
The fan control should be the on/off switch. Does it click off when turned one way? A bad control may still show varying resistance but it still may be too high. A way to check is remove the fan control and thermodisk from the circuit and run direct. The fan should run at full speed.