What can I do with this motor I found?

strantor

Joined Oct 3, 2010
5,369
I say it would put out DC, and that the level of DC would depend on the speed of the turbine and load on it (loading will slow down the turbine). I would suggest a battery bank as a buffer between your turbine and circuit; that would smooth out the effects of changing load as well as smoothing out effects of changes in wind velocity.
 

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tom66

Joined May 9, 2009
2,595
I say it would put out DC, and that the level of DC would depend on the speed of the turbine and load on it (loading will slow down the turbine). I would suggest a battery bank as a buffer between your turbine and circuit; that would smooth out the effects of changing load as well as smoothing out effects of changes in wind velocity.
I'll leave the bridge rectifier in there, in case I upgrade to a different motor or happen in my infinite genius to reverse the polarity. The caps provide a temporary battery, along with the fact that it can run from low input voltages and still produce 340V DC. But I'll see how it all fits together when I get the motor hooked up to the scope and slowly turn it. If it's low voltage (<100Vp-p), it might make more sense to make a buck, SEPIC or flyback converter and feed a standard 12V automotive inverter.
 

davebee

Joined Oct 22, 2008
540
I'd suggest testing it before making too many plans - figure out how to wire it and run it on the bench.

Maybe the reason that a used motor had been removed from an appliance was that it had failed.
 

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tom66

Joined May 9, 2009
2,595
I'd suggest testing it before making too many plans - figure out how to wire it and run it on the bench.

Maybe the reason that a used motor had been removed from an appliance was that it had failed.
It's quite plausible that it has failed, so I'll be testing it as soon as I get my hands back on it.
 

K7GUH

Joined Jan 28, 2011
190
A 3/5 HP motor is hefty enough to run a drill press, light duty table saw, or a blower. I would keep it on a shelf until someone (maybe moi) has a use for it.
It will need a step down pulley but that shouldn't be expensive.
 

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tom66

Joined May 9, 2009
2,595
Okay, so I got the motor home.

First thing I did was try to scope the voltages on each of the connections relative to earth. When turned I got about 30mVp-p AC on some of the connectors.

So I heard you need to apply a voltage to the field to get these things to work. Did that (applied about 12V and the field pulled around 50mA), but still the same 30mVp-p.

It's possible the motor is bust, but the fact that I'm getting any voltage seems to suggest otherwise. Then again, I know very little about motors.
 

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strantor

Joined Oct 3, 2010
5,369
Well, did you try running it as a motor? if it's a no-good motor then its going to be a no-good generator. and I still maintain my prediction that it won't be a good generator.
 

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tom66

Joined May 9, 2009
2,595
Well, did you try running it as a motor? if it's a no-good motor then its going to be a no-good generator. and I still maintain my prediction that it won't be a good generator.
How would I configure it as a motor? (bear in mind I haven't touched anything other than a 3 phase brushless motor on my RC aircraft.)

I have a 0-35V DC power supply (up to 3A), and 230V mains available. I was using the 0-35V supply to run the field.
 

strantor

Joined Oct 3, 2010
5,369
http://www.allaboutcircuits.com/vol_2/chpt_13/12.html

you need to find out what all those wires are. I suspect there may be several field windings, or several taps off the same field winding for several speeds; I'm not sure of this. a true, basic univeral motor should only have 2 leads coming out of it; in order to make it into a generator, you would have to go into the motor and bring the field winding leads out and seperate them. Since you said you already put current through the field, that makes me think they are already brought out on this motor.

Actually, after looking at your last picture, if I am looking at it right, you have connected the power supply to the 2 red wires coming out of the end? I don't think that's the field. Not sure what it is, maybe some kind of temp or rotation sensor or switch. I see the a grey wire coming out of the brush housing and into the stator; that probably connects to the field winding inside the motor.
 

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tom66

Joined May 9, 2009
2,595
Yes, there are two red wires running into something at the rear of the motor. I kind of assumed these were the field windings, but I suppose I was probably wrong.

I found the washing machine this motor was used in. Of particular note is page 8 which seems to show a 7 pin connector going to the main drum motor. 1, 2 and 3 seem to be a field maybe? They have a TRIAC controlling them. 4,5 seem to be the motor itself. 6,7 might be a temperature sensor, or maybe a tachometer -- they might be the red wires I've been thinking are the field.

Among the pile of junk, I think I also found the CUIO board.
 

strantor

Joined Oct 3, 2010
5,369
that looks promising; the field could be switched for rotation in either direction, and then goes through a variable resistor, which would control the current in the winding for 2 seperate speeds. I only count 6 wires in your connector though; is ther a wire missing between the black and the brown, or between the brown and the reds?
 

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tom66

Joined May 9, 2009
2,595
That's a good point, there are only 6 wires.

Two red wires go to the tacho/temp sensor. They go straight to the rear of the motor.

There's an earth point, which has a connector pin which is similar to the rest inside the plastic white connector, so maybe one end of something is connected to earth - perhaps a common terminal or such - or maybe a design revision?

There is a grey wire which goes to a brush on the right hand side. And there is a blue wire which goes to a brush on the left side.

There then appear to be two wires left; a brown and a black, separated by a gap in the connector. Maybe the field? Is the stator powered using the brushes?

The motor is reasonably new. Date code 28th week of '06.

Idiot question: What would be the minimum number of connections to get this to run from 12 - 24VDC?
 

strantor

Joined Oct 3, 2010
5,369
That's a good point, there are only 6 wires.

Two red wires go to the tacho/temp sensor. They go straight to the rear of the motor.

There's an earth point, which has a connector pin which is similar to the rest inside the plastic white connector, so maybe one end of something is connected to earth - perhaps a common terminal or such - or maybe a design revision?

There is a grey wire which goes to a brush on the right hand side. And there is a blue wire which goes to a brush on the left side.

There then appear to be two wires left; a brown and a black, separated by a gap in the connector. Maybe the field? Is the stator powered using the brushes?

The motor is reasonably new. Date code 28th week of '06.

Idiot question: What would be the minimum number of connections to get this to run from 12 - 24VDC?
ok, so something is missing, per design (maybe slightly different or less-featured model); there are some things we can eliminate: it's not either of the armature wires (because it wouldn't run otherwise), it's not either of the field wires (because it wouldn't run or switch direction otherwise), and its not either of the tacho wires (because we already verified they're there) so it must be one of the wires coming back from the variable resistor. did you see a variable resistor anywhere on the motor? I didn't.

so you need to figure out which of the pairs of wires are the armature and which are the field. the field will have a higher resistance than the armature.

EDIT: armature you verified is the blue & grey. so the other two wires (brown & black) I assume are the field. if you jumper blue to black and then apply power to grey & brown, I would expect to see some movement. Be careful though, it may spin fast. be ready to remove power.
 

Thread Starter

tom66

Joined May 9, 2009
2,595
Yes! It works!

I connected a 9V zinc carbon battery to the field windings. Just to provide the required magnetic field, I think?

Then I connected the remaining brush lines to my power supply. The motor will run at 5V and produces a pretty good speed at 35V. It also works pretty well as a generator, powering the power supply for about 10 seconds after it is switched off (I can see from the voltage readout.)

The only problem I'll have with making this into a wind turbine is generating sufficient voltage. I'll need to either gear the motor, or find a very windy day, or go for a low voltage -> high voltage conversion and then invert that into AC, or just power a standard 12V-24V automotive inverter with a SEPIC/isolated flyback converter.
 

strantor

Joined Oct 3, 2010
5,369
awesome! now play around with different currents in the winding and see how that effects the voltage produced. remember current through the winding is what's important. I'm not sure what the DC resistance of the winding is, but going any higher than 9V with no current limiting might damage it (not all sure of that statement; just a guess). as a motor, the less current through the winding, the faster it will go and the less torque it will have. what that means as a generator? I don't know, never tried it.
 

Thread Starter

tom66

Joined May 9, 2009
2,595
Yes, the 9V battery is "current limiting", as it gets very warm after about 5 minutes of motor use.

In future it would be good to go without a separate field winding. I have some neodymium magnets, would they work to provide a constant field for the motor?

Also, the motor seems to draw a fairly fixed 1A on the brush terminals, independent of voltage (it seems to mostly depend on load.) An increase in voltage causes a substantial increase in speed. Since the sensor at the rear is probably a tacho, I'll try measuring the motor RPM using an oscilloscope later.
 

strantor

Joined Oct 3, 2010
5,369
there is a lot of engineering that goes into designing a motor. much more than I or anyone I know knows. if you decide to rip the field winding out and try to replace it with magents, I fear that will be the end of your motor; but hey, it was free and what better way to learn than by trial and error?

That tach is probably a DC tachogenerator (guess, based on the fact that it drew a steady current when you thought it was the field winding) meaning, it won't tell you RPM based on pulses, but based on a DC level.

My recommendation (assuming your goal is to make a working generator, and not to engage in a learning by trial & error excercise) is that you either continue with your generator plans using this motor, and accept the fact that you need to supply the field with a current, or you find a permanent magnet motor.
 
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