Help identifying wires from antique fan

[thebigjoe1]

Restoring an old westinghouse desk fan from 1919. There are three wires coming from the fan head (motor) labeled G, Y, and R. Can these be identified for me, ie positive, negative, ground? Thanks!

 

[Avo Mk8]

Antique Fan Collectors Association the place to go:

Antique Fan Collectors Association

Members Discussion Forum

www.afcaforum.com

Hopefully that inductor/autotransformer component is still in good health!

 

[Lucien Nunes]

True series-fed transformer split-phase. Not a configuration one sees around these days. The transformer doesn't really function as an autotransformer as such, because the 'primary' is exclusively in series with the main winding while the 'secondary' exclusively supplies the auxiliary winding (shown on the dwg as as 'starting winding' but that is a bit of a misnomer.)

The windings share a common terminal to minimise the number of wires from base to head. I would describe these as:
Green: Main winding
Red: Auxiliary winding
Yellow: Common

positive, negative, ground

With AC power there is no positive or negative. The distinction you were looking for is hot and neutral, which are unrelated to positive and negative. Neutral is the wire connected to ground at the source and in the main panel, while hot is the one that is not. In contrast, negative (of a DC source like a battery) is the wire that has a surplus of electrons and positive is the one that seeks electrons.

 

[thebigjoe1]

Antique Fan Collectors Association the place to go:

Antique Fan Collectors Association

Members Discussion Forum

www.afcaforum.com

View attachment 87647
Hopefully that inductor/autotransformer component is still in good health!

Avo and Lucien,

Below is my crude wiring diagram. I got the fan to work, prior to looking at this, but it does sizzle, smoke, and smell like something is burning from the fan head/motor (i unplugged immediately). According to your diagram, it looks like the G would go to the AC source, not R, but im not sure where R and Y go. Based on my diagram could you you help?

Regards

 

[thebigjoe1]

i think i got it, R goes to red on the coil, and Y goes to black on the coil. Unfortunately this did not work. I can hear a hum, when i turn on the switch but nothing more.

 

[Lucien Nunes]

Your diagram shows an incorrect connection. The red wire from the motor should not connect to either of the screw terminals where the power cord is attached. It should connect only to the (probably red) wire from the transformer.

We now need to confirm that all the coils have continuity and are not short-circuited. Do you have a multimeter that you could use to take a few resistance measurements?

 

[Avo Mk8]

Lucien is of course right. You really do need a multimeter, both to check the motor windings still are the correct resistance (values in a posting on the AFCA site) and also to confirm the transformer connections. I think the wiring goes as my sketch below, but I'm making a rash assumption that the black wire (from the coil) is a tap on the winding of the transformer, rather than the end of it (you could establish that with the multimeter!).
NB Sorry for any confusion in the sketch - the faint line from the (L) terminal was supposed to indicate the lever of the switch - it's not a connection to the coil or red wire.

Do find a multimeter and carry out some checks rather than take pot luck and damage it!

 

[thebigjoe1]

Lucien, i have a multimeter, yet sadly am not an expert at using it. if you can give me some tips on how to properly use it so that i can take the necessary measurements, id greatly appreciate it.

Avo, The way you have your diagram, i tested late last night, and all i get is a hum from the motor when i switch it to on.

 

[Avo Mk8]

Lucien, i have a multimeter, yet sadly am not an expert at using it. if you can give me some tips on how to properly use it so that i can take the necessary measurements, id greatly appreciate it.

Avo, The way you have your diagram, i tested late last night, and all i get is a hum from the motor when i switch it to on.

That's great that you have a meter.
I will leave guru Lucien to suggest measurements.
There is one thing you could clarify for me - with your multimeter switched to a low ohms range - we want to measure tens of ohms probably - touch the probes together and check the meter reads about zero!
Then with everything disconnected, included my suggested connections, measure firstly between the red and black coil wires and note the result. Then measure between the black coil wire and the stud on the right (max speed setting) and note the resistance. In fact you might note the resistance to all the studs in sequence.
Grateful if you could let us know the results.
Regards
PS Once you have become expert at measuring resistances, I suspect Lucien would like to know the measured values between the three fan wires: green to red, red to yel, yel to green. I certainly would!

 

[thebigjoe1]

My meter does not let me select the different levels, its an auto range meter.

So just putting them on the terminals of the AC, not plugged into wall, it measures in at .017. If i then put them on the red and black wires from the coil it read .041. Does that seem correct, and if so any issues?

 

[Avo Mk8]

My meter does not let me select the different levels, its an auto range meter.

So just putting them on the terminals of the AC, not plugged into wall, it measures in at .017. If i then put them on the red and black wires from the coil it read .041. Does that seem correct, and if so any issues?

Hi
does the meter indicate the unit of measurement, ie K ohms?
If it does, it means the coil is 41 ohms, which sounds OK, and the resistance across the mains plug is 17 ohms, which seems rather low.
could you measure between each coil wire and the 'high' switch contact (furthest from 'off'), with the motor wires disconnected?

just to clarify - with your measurement across the plug, which position is the sliding lever in?

And Lucien's post at the same time as mine suggests a far more methodical start. So ignore my misguided suggestion to check if the coil is connected correctly!

 

[Lucien Nunes]

My first move would be to check the resistance of the two motor windings and confirm the leads are correctly labelled. Because if there is something wrong with the motor then nothing else matters until that is repaired / rewound.

With the motor disconnected from the base, measure the resistance from each lead to each other lead and from at least one to the motor body. When the meter autoranges it will display the unit: Ω, kΩ or MΩ and you must check and state this ewith every measurement.

 

[thebigjoe1]

This is the multimeter i am using. I had it on V. Tell me where i should have it positioned.

@ avo slider level was in off position.

 

[Lucien Nunes]

As it is now, on resistance (Ω) All resistance measurements must always be made with the fan unplugged from the wall outlet. The measurement unit will be shown in the top right hand corner along with the digits.

Black meter probe must be in COM, red probe in VΩ

 

[thebigjoe1]

So with it on resistance, it read 0L. I put the red probe on what i have as hot and black on neutral (AC Wire terminals). I also did the same on the red and black wires from the coil, and it reads the same. Not sure if im doing something wrong. Sorry i am a newbie with respects to a multimeter.

 

[Avo Mk8]

If you connect the meter probes together, does it read something like "0.01", different to OL?
If it does you are not doing anything wrong.
When taking your measurements, "OL" is reporting an open circuit.

You would need to move the fan speed lever to an 'on' posirion to get a reading across the AC input terminals, but with 'OL' across the coil terminals, that's suggesting a problem with the transformer.

Could you just confirm that touching the probes together changes "OL" to a low value reading?

 

[thebigjoe1]

I can confirm touching two probes together gets low reading. Also with the switch in on position, there is still no reading on Ac input terminals..... same with coil.

But, if i keep probe on Hot terminal, and then probe anything else, i get readings from different wires or terminals that i touch (not neutral terminal)

 

[Lucien Nunes]

Please can we test the motor first. It has fewer unknowns and the results can be cross-checked.

With the three motor wires disconnected from the base, test:
Green-Yellow (main winding)
Red - Yellow (aux winding)
Green - Red (both in series, reading should be the sum of the two above)
Yellow - motor body (should read OL)

Please post all four resistances.

 

[thebigjoe1]

With the mutlimeter, am i supposed to touch red to green, and black to yellow? Vice versa? or is there another way. Again, i apologize for my lack of knowledge on how to actually use the mutlimeter.

 

[Lucien Nunes]

For most resistance measurements it doesn't matter which probe is which. Here, for example, the windings are just copper wire so makes no difference which way the multimeter's test current flows through them.