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Discussion Starter · #1 ·
Hey guys, a contractor we are working for has this fan that wasn't working properly and asked me to take a look at it. He had already took the circuit apart and I tried to put it back together. It's a 3 speed 120 volt motor. I have 8 leads coming from the motor into the control box.

Green - Ground
White - Neutral
Grey - Start Winding
Red - High Speed
Yellow - Med Speed
Brown - Low Speed
Black - ?
Black - ?

I found this wiring diagram and hooked it up like it showed not hooking the 2 blacks to anything because I am not sure what they are and the fan works, just rotates in the wrong direction. Now I know this fan is just a piece of :censored:but I just have to figure it out haha. Any idea what those 2 black wires are? They have no continuity or resistance to any other wire. Thanks.



I also hooked it up like this one not using the 2 blacks and it rotates in the right direction just not very fast.

 

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I would look up the diagram for the motor from the manufacturer
and properly identify the leads.
also identify the conductors color and function for your region
according to the second diagram you are switching a neutral (if you are using single phase)
 

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8V71 said:
The two blacks could be thermal protection. Do they meter close to zero ohms between themselves?
If it was a compressor, I would agree. I don't know if fans have external leads coming out. If the two blacks are open to each other, that might be what started this whole thing.
 

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nmackintosh said:
Hey guys, a contractor we are working for has this fan that wasn't working properly and asked me to take a look at it. He had already took the circuit apart and I tried to put it back together. It's a 3 speed 120 volt motor. I have 8 leads coming from the motor into the control box. Green - Ground White - Neutral Grey - Start Winding Red - High Speed Yellow - Med Speed Brown - Low Speed Black - ? Black - ? I found this wiring diagram and hooked it up like it showed not hooking the 2 blacks to anything because I am not sure what they are and the fan works, just rotates in the wrong direction. Now I know this fan is just a piece of :censored:but I just have to figure it out haha. Any idea what those 2 black wires are? They have no continuity or resistance to any other wire. Thanks. I also hooked it up like this one not using the 2 blacks and it rotates in the right direction just not very fast.
What kind of fan is this? And AHU blower, ceiling fan, kitchen exh???
 

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I would start the motor spinning in one direction, then turn it on. If it stays in that direction when powered, shut it off.

Start it spinning in the other direction, and add power. If it stays spinning in that direction, shut it off.

Then find the right cap for it.
 

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Discussion Starter · #14 ·
I would look up the diagram for the motor from the manufacturer
and properly identify the leads.
also identify the conductors color and function for your region
according to the second diagram you are switching a neutral (if you are using single phase)
Talked to the manufactor and they dont have a wiring diagram for it
 

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nmackintosh said:
Hey guys, a contractor we are working for has this fan that wasn't working properly and asked me to take a look at it. He had already took the circuit apart and I tried to put it back together. It's a 3 speed 120 volt motor. I have 8 leads coming from the motor into the control box. Green - Ground White - Neutral Grey - Start Winding Red - High Speed Yellow - Med Speed Brown - Low Speed Black - ? Black - ? I found this wiring diagram and hooked it up like it showed not hooking the 2 blacks to anything because I am not sure what they are and the fan works, just rotates in the wrong direction. Now I know this fan is just a piece of :censored:but I just have to figure it out haha. Any idea what those 2 black wires are? They have no continuity or resistance to any other wire. Thanks. I also hooked it up like this one not using the 2 blacks and it rotates in the right direction just not very fast.
ive seen some consumer grade permanent split-phase motors that include a LV secondary winding for powering some electronic circuits - such as a timer board. Do you have any voltage reading emanating form the black leads?

I've also seen fans like that where the AC line is applied to the blacks and the switch just operates the taps
 

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Nukie Poo said:
ive seen some consumer grade permanent split-phase motors that include a LV secondary winding for powering some electronic circuits - such as a timer board. Do you have any voltage reading emanating form the black leads? I've also seen fans like that where the AC line is applied to the blacks and the switch just operates the taps
they usually do this because there are two thermal fuses inside the motor winding to open both sides of the line in case of a burnout
 
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