I have been lurking for awhile now.

I was at a local scrap yard today and came across a permanent magnet motor. I have been wanting to play around with a DIY generator for some time now.

Anyways i ended up buying it. it is very heavy(70 lbs) it says 220 volt dc 17.0 amps and 4 hp is this something that can be used or is it to big?

i can spin it by hand and get 25-30 volts ac out of it np at all. if i put my meter on dc i can get about 7-10 volts. no load of coarse.

i assume after i figure out how i want to spin it then i wire the + and - into a charge controller and then to a battery or a bank of batteries.

I want to use it to recharge batteries at the cabin.

what would you guess i could get out of this at say low rpms (say 250) and at high rpms (say 2500)?

Any thoughts and help would be greatly helpful.

http://www.jwarfieldelectric.com/com....html?Itemid=0

4 horsepower 17amp 220voltz DCContinuous Duty Electric motor

 

If you either back feed it with another motor at a known rpm and read the generated voltage, or apply a voltage and read the rpm via a tach, the voltage at 2500rpm can be extrapolated.
It appears to be 220vdc at 2500rpm according to the label, this is a servo motor you have there.
Max.

 

so this motor is usable then?

think that under a load at slow rpm i will put out decent power to rechage batts?

I am new to this whole thing but interested in learning about it more.

 

The continuous torque (current) rating appears to be 17amps.
Bit of a waste to use a good servo motor for that, any T.M. motor would do the trick.
Max.

 

this is out of a commercial treadmill believe it or not. i bought it out of scrap yard for $28.00

let me see if i understand this right........i spun it at just 70 rpms with no load and it was reading 10 volts. does that mean i was producing 170 watts at that speed?

 

there was another one there also. maybe i should go get it also.

 

let me see if i understand this right........i spun it at just 70 rpms with no load and it was reading 10 volts. does that mean i was producing 170 watts at that speed?

Unless you were also connected to something that was drawing 17 amps while you were putting out 10 volts then no.

As far as using it as a DC generator it will work fine. Just make sure you don't pull much over 17 amps for extended time periods. High currents for a few seconds wont hurt it nor will moderate load in the 20-25 amp range for a minute or two.

If you can get the second one for another $28 then by all means do so! Larger PM DC motors like those are rather spendy to buy new!

 

so i should be just fine with it as a battery charger then. a 17 amp draw is pretty high for most items( household items anyways).

So i can go from this motor wired to a charge controller then to a battery correct?

 

this is out of a commercial treadmill believe it or not. i bought it out of scrap yard for $28.00

let me see if i understand this right........i spun it at just 70 rpms with no load and it was reading 10 volts. does that mean i was producing 170 watts at that speed?

They are one of the higher quality T.M. motors, something does not jive with the numbers you got?
As tcmtech said that test has nothing to do with watts, you essentially had no load.
If the label is to be believed then the 17amps is the continuous current it is capable of.
You need to govern or regulate the output in some way if you are feeding into a battery bank.
What is the nature of your charge controller? Not AC supplied I assume?
Max.

 

i havent bought a charge controller yet. Should i just get rid of this motor and get something else.

I am hoping to find a cheap option from the scrap yard that would be able to put out decent amps to charge the batteries at lower rpms. i will probally use it with a water wheel at the property.

I know wishful thinking.

Not sure if anyone would buy this motor due to shipping cost or not.

 

Oh I would be very interested in both units!

Send me a PM and I will deal with you on them if you want to make a bit of easy money.

 

i cant find the pm button for you. odd

 

Hmmmm......... I cant find any PM buttons for anyone.

 

removed information.

 

I did a quick online check and it would appear you are from Genesee Michigan.

Any guess on the motors weight and actual shipping dimensions? Given my rough estimates shipping to me for one motor would be between $30 - $45 which is well within my acceptable cost range.

 

i just measured it. It is 10"x10"x20"
when i bought it it was coming in at 70 lbs.

 

fed ex seems the best price at 59.00 for shipping.

ups was 73.00

i dont think usps does anything over 70 lbs

 

That works just fine for me. I wasn't expecting 70#'s though. Does it have a big flywheel on one end?

All of the treadmill motors I have picked up had a massive flywheel weight on them that weighs nearly as much as the whole motor. If so I have no use for that.

 

yes it has the large flywheel that probally is about 15 lbs i would guess.

Feel free to text me and we can see if we can work out a price for it.

It seems like to me that this unit would be great at low rpm for charging batteries.

Maybe i just dont understand how it works.

 

Yes it would work just fine as a low RPM DC generator.

That said I can put it to use just the same if you have no use for it or want to make some easy money and pick up the second unit and sell that one to me!
(Or sell me both.)

And yes I have no use for the flywheel so I would like a weight estimate without it. At 70 #'s for a 4 HP motor I am suspecting that flywheel might be more in the 20 - 25+ # range which to me is just wasted money on shipping.

BTW I don't text.