Microwave Fan and Voltage rating?

Thread Starter

BarryTron

Joined Nov 18, 2018
83
So I have several fans that I took out of the old microwaves and they are labeled 120V 60Hz 0.3A MAX.Z. I would like to connect them to 120V so that I can fan away fumes when soldering.

After connecting one and burning it up (it worked for about five seconds) I decided to turn to here for help.

Any recommendation would be appreciate,

fan.jpg

-m
 

AlbertHall

Joined Jun 4, 2014
10,558
Did the motor turn for those 5 seconds?
Did it make smoke signals and, if so, where from?
In the second picture it looks like there is no tape covering the motor winding. It somewhere the insulation on that wire had been damaged that might cause trouble.
 

Thread Starter

BarryTron

Joined Nov 18, 2018
83
Did the motor turn for those 5 seconds?
Did it make smoke signals and, if so, where from?
In the second picture it looks like there is no tape covering the motor winding. It somewhere the insulation on that wire had been damaged that might cause trouble.
Did the motor turn for those 5 seconds? > Yes
Did it make smoke signals and, if so, where from? > Yes, a pop sound and smoke. Did not see the location of the smoke, what trying to cut the power.
In the second picture it looks like there is no tape covering the motor winding. > They are all like that.
somewhere the insulation on that wire had been damaged that might cause trouble > They all came out of working microwave. Took them out with care.
 

Ylli

Joined Nov 13, 2015
986
Try another one. I don't think you did anything wrong, and the motor is clearly labeled 120V 60Hz, 0.30 A max, Impedance Protected. The latter means that even if the fan is not allowed to turn, it should not damage the motor.
 

Thread Starter

BarryTron

Joined Nov 18, 2018
83
Try another one. I don't think you did anything wrong, and the motor is clearly labeled 120V 60Hz, 0.30 A max, Impedance Protected. The latter means that even if the fan is not allowed to turn, it should not damage the motor.
Try another one. I don't think you did anything wrong, and the motor is clearly labeled 120V 60Hz, 0.30 A max, Impedance Protected. The latter means that even if the fan is not allowed to turn, it should not damage the motor.
I should have mentioned that the moto winding was very hot after the pop.

Do I have a way to set it up such a way that I can protect that from happening when testing another, would hate to burn up another one?
 

Ylli

Joined Nov 13, 2015
986
Try a DBT (dim bulb tester). Put a small incandescent lamp in series with the line and the motor. Start with a 25 watt bulb. If the motor runs and the bulb lights only dimly, that tells you the motor is not drawing excess current. The get the motor to full torque, you may need to use a higher wattage bulb. Try 60 W and then if all is well, 100W.

Alternately, if you post the make and model of the microwave they came out of, perhaps someone can find a schematic and confirm whether or not the motor was fed 120 VAC.
 

Thread Starter

BarryTron

Joined Nov 18, 2018
83
Try a DBT (dim bulb tester). Put a small incandescent lamp in series with the line and the motor. Start with a 25 watt bulb. If the motor runs and the bulb lights only dimly, that tells you the motor is not drawing excess current. The get the motor to full torque, you may need to use a higher wattage bulb. Try 60 W and then if all is well, 100W.

Alternately, if you post the make and model of the microwave they came out of, perhaps someone can find a schematic and confirm whether or not the motor was fed 120 VAC.
The label indicates { 0.3A MAX }. Would that be 36W? If that is the case, how would one go about providing 36W without a bulb? I never had to care about Watts on AC before, only Volts.
 

MaxHeadRoom

Joined Jul 18, 2013
21,630
In spite of the fact they are marked 120v, some M.W. oven fans operate on a series winding on the transformer, I would suggest trying one on low voltage AC, say 24v and see what happens.
Many run on an oddball voltage of 21vac
Max.
 
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Ylli

Joined Nov 13, 2015
986
The label indicates { 0.3A MAX }. Would that be 36W? If that is the case, how would one go about providing 36W without a bulb? I never had to care about Watts on AC before, only Volts.
The bulb is simply acting as a current limiting resistor. MaxHeadRoom may be right - he generally knows his stuff. Do you know the make/model of the microwave?
 

Thread Starter

BarryTron

Joined Nov 18, 2018
83
In spite of the fact they are marked 120v, some M.W. oven fans operate on a series winding on the transformer, I would suggest trying one on low voltage AC, say 24v and see what happens.
Many run on an oddball voltage of 21vac
Max.
Will give it a try. But i don't understand why would it be labeled as 120V if it can only take 24V?
 

PeeSeeBee

Joined Jun 17, 2011
56
There is a third terminal in the photo. Was anything connected to that before you removed it from the oven?

Does that third terminal have a wire from the motor winding soldered to it?

I'm wondering if the motor winding is tapped & that the 120v rating applies to the outer windings?

Having said that, the physical position of the terminals doesn't always correspond with the position of the tap. Perhaps the winding is tapped, but is brought out to the unused terminal?
 
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Ylli

Joined Nov 13, 2015
986
Lots of google hits on "OEM-1011X1", but nothing definitive as to the voltage ratings. Apparently, it is used in many different microwaves.
 

PeeSeeBee

Joined Jun 17, 2011
56
Ooh! Well spotted. I think some resistance readings between the three terminals of a non-popped motor are needed.
Yep.

OP...I wouldn't recommend that you power up onother motor until taking some resistance measurements as AlbertHall suggests.

Looking at some photos online, that 3rd terminal is connected to the winding. I've a feeling that the outermost terminals are going to give the highest resistance reading & that's where the 120v should have been applied.
 

MaxHeadRoom

Joined Jul 18, 2013
21,630
Will give it a try. But i don't understand why would it be labeled as 120V if it can only take 24V?
There is a Utube video of someone experimenting with the same fan and it shows a tapped winding, but the video does not go into the difference unfortunately.
It is possible it is dual voltage purposed.
Also this video shows all three connected, with what looks like the hot side to one of the outer terminals.


Max.
 
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Tonyr1084

Joined Sep 24, 2015
5,239
Just a guess here, but my guess is that it may have been used as a way for the control board to determine if the fan was running or not. It MIGHT have been a protection for the whole microwave oven. But this is just a guess.

I also agree, resistance testing should be done before any more voltages are applied.

I do have one comment that is not guesswork - and that's using that fan to blow away smoke from soldering. First, I believe the air movement is going to be too fast and harsh. If you blow the fan AT your work you'll likely cool your iron before you can accomplish the soldering work you want to do. Blowing away, as I have a small 12 volt fan doing, will gently attract the smoke and blow it away from my face. Otherwise without the fan, no matter where I sit, the smoke always seems to find my face. Sort of like barbecuing.
 

thedoc8

Joined Nov 28, 2012
151
Yep.

OP...I wouldn't recommend that you power up onother motor until taking some resistance measurements as AlbertHall suggests.

Looking at some photos online, that 3rd terminal is connected to the winding. I've a feeling that the outermost terminals are going to give the highest resistance reading & that's where the 120v should have been applied.
I found this comment also:
Use the 2 outermost as connections. The fan often has a winding used to run the turntable motor, which typically runs on 24VAC or 43VAC. Check DC resistance and use the 2 with the highest resistance between them. That will be the outermost ones in most cases. If you look carefully one will have 2 wires connected that runs into the winding. Do not use that one.
 

MaxHeadRoom

Joined Jul 18, 2013
21,630
Use the 2 outermost as connections. The fan often has a winding used to run the turntable motor, which typically runs on 24VAC or 43VAC. Check DC resistance and use the 2 with the highest resistance between them. That will be the outermost ones in most cases. If you look carefully one will have 2 wires connected that runs into the winding. Do not use that one.
Although if using the motor stator as an auto transformer, I would expect to see the highest res winding used as the fan and the low one used as the aux out.
Not both in series for the supply, but it may not be a problem if the aux is fairly low output, as long as it is wound in the same direction.
Max.
 
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