I Have a very very low rpm PM motor .will it work?

[divemaster1963]

I Have gotten a PM motor form a firetruck hose reel. It is a 12v dc motor with 35 amps at 100 rpms. Can I use this for a windmill motor in a low wind zone? My winds avg. 6 to 8.6 pmh during the year. and if so what would this best blade length to use. I plan on making a furling system. what angle sould I use to control rpms?

[tecker]

If you spin it to 100 with a drill you'll see but the ratio is not in your favor .You can get charge at 6  and dump to 12 with a dumper works very well . You have to checkit out to be sure.

[ghurd]

Sounds like a geared motor.  Not good.

G-

[CmeBREW]

Hello,  

      That is a rare DC motor. Do you have any pictures you can show?

My brother has one similar on his carpet cleaning van hose reel. Fortunetly, the motor is not a gear motor since it uses the entire diameter of the steel hose reel as a giant 'gear'. The steel hose reel has steel gear teeth all the way around it.

It is an interesting motor. We changed the brushes inside and it has many ceramic magnets (many poles) inside it and the wire gauge is decent size-- so it might make a decent small diameter windmill. Does It have ball bearings?

If it has at least a shaft size of 5/8" you could try a set of 5-6' diam pvc blades on it and see how it does first. I recall the motor had some cogging.

Matching a random motor to a set of blades is not always easy. I make pvc blades long and then cut them down little by little as I watch performance over the months. Then make wood blades to that size.

It would also make a good 80-100W bike pedgen.

 

[divemaster1963]

I cleaned up the motor and found i made a mistake. it is 12vdc 35 amp at 650 rpm. it has for very strong 4 by 2 inch. magnets moounted to the huosing. I tried a drill attached to it and got 8volts at 20 amps at medium speed. it has sealed bearings on both ends of the shaft. I had a 2nd. burnt up. took it apart. it has heavy gauge winding on the field. it turns like a dream. very very little cogging. is there a way to step up the voltage to 12v. I have a bank of 8 240aph batterys.sealed agm telecommunication back up batteries rated for 13.6 volts max.  I thankyou for the info I have a big learning curve.

[CmeBREW]

My bad. So they are not that rare and special after all. My brother's motor is called "White Magic" but gives no ratings anywhere. When I saw all those ceramic magnets in it I thought it would be good--but now like yours it looks like it needs around 700rpm to even reach 12v cut-in. Thats very fast. Too fast for me.  You could try to make your own fast 4'diam.  wood blades, and it would do something on windy days.   It is good the cogging is very small.  Or you might try a voltage doubler circuit here if you search for them.

Nice batteries. Make sure you keep'em fully charged.

Sounds like you really need to make a 8'-10' alternator mill.    

[divemaster1963]

I have been doing some searching on the net. would using dc to dc mutipler help bring up the voltage at lower rpm so the cut-in voltage would work. what do you think.

I'm up for any input thanks

[CmeBREW]

This is a problem many (including myself) had/have when they start out using  DC motors of sorts. I am not very good on the electronics, but if I recall the simple voltage doubler circuit could only do little current. Not worth much. It seems to me, Dc to DC converters are complex and/or expensive and use up power that one can't afford to lose with a small 4' mill in a simple system.

Since you said the cogging on the motor was very little, and if you have a good, clean wind location you might still try making a simple 2-bladed wood prop which would be very fast and go well over 700rpm quite a lot in medium to strong winds.  I believe many 4' mills (like 'Air-X, etc.)often go over 1500rpm in good winds. So if you make the blades good and balanced, you have a good chance having something useful. It is much better than nothing on sunless, gloomy days when solar panels do almost nothing but the winds blows decent. But you still have to have solar panels because usually when the sun is shinning the wind is not blowing. (where I live anyway)

Sorry there is no easy answer for that...or all beginners would be doing it!

[Norm]

  How much easier it would be if posters with a

motor would simply wrap a rope around a drum

about 1 inch in diameter by 1ft.long very tight

fit onto the shaft.

  wind up various weights until just heavy enough

to overcome the cogging....now we will Know how

Much It Cogs.... 'very little cogging' tells us

nothing !  same goes with ' it lights up a light

bulb or a led with a flick of my fingers'

A better example: A 50 pound weight around the

 (1 inch) drum puts 5 amps into my 12volt

battery ....the weight traveled 3 ft. per second.

(just an example).

Hope you guys get my drift of what I'm trying to

say ?

  It really doesn't take that much time and this

method is a lot more accurate than using a

cordless drill and saying it was about 700 rpm

but then the batteries weren't full charged and

who knows how much torque was involved ??