trying to test a motor

coboda
coboda Registered Users Posts: 6 ✭
in Wind Power Generation #1
I just got a dc permanent magnetic motor off an old treadmill, according to my calculations it should produce 24v @ 450rpm
I'm trying to test the voltage output with a voltmeter by connecting it to the terminals and hand spinning the shaft but I'm not showing any output.
any suggestions?
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: trying to test a motor

    If you have connected your meter to the right terminals on the motor, and if the motor is indeed a DC motor, and if the meter is good and set to read low voltage DC, then I would expect a problem with the motor. BTW, even if you get the motor to work, IF you are thinking of using it as a generator, do not expect a lot of power from it. Yes, it should give you 24 volts alright, but it won't produce a lot of amps or watts due to it having been wound with small wire, to run as a motor off a much higher voltage.
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  • coboda
    coboda Registered Users Posts: 6 ✭
    #3
    Re: trying to test a motor

    I get an ohm reading and a DC amp reading, DC volts only read when my dial is set to 200m, but I get no reading on 200. the motor I got is rated @ 1725rpm 115v and 8.5 amp so techinically if at 450rpm i generated 24v shouldn't that give me about 204 watts?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: trying to test a motor

    Power is not a linear function of RPM.
    Spin it with an electric drill for testing purposes.
    Don't get your hopes up.
    Motors still aren't generators, nor are they designed to last outdoors in weather (if you were thinking of making a wind turbine from this).
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  • coboda
    coboda Registered Users Posts: 6 ✭
    #5
    Re: trying to test a motor

    well after messing with this damn thing for two days I just found out it was an ac motor haha
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #6
    Re: trying to test a motor
    coboda wrote: »
    well after messing with this damn thing for two days I just found out it was an ac motor haha

    More likely it is a DC motor with circuitry attached to it to make an AC fan module.
    Circuitry also called "steering diodes", as mentioned in an earlier post. :-)
    SMA SB 3000, old BP panels.
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  • coboda
    coboda Registered Users Posts: 6 ✭
    #7
    Re: trying to test a motor
    inetdog wrote: »
    More likely it is a DC motor with circuitry attached to it to make an AC fan module.
    Circuitry also called "steering diodes", as mentioned in an earlier post. :-)

    Well I ended up getting another motor that work, but the other one has a better voltage/rpm ratio so how would I bypass the circuitry?
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  • westend
    westend Solar Expert Posts: 46 ✭
    #8
    Re: trying to test a motor

    It would be helpful if you list the items off the rating plate of the motor,i.e. AC, DC, RPM, Load A, V, HP.

    I have a permanent magnet DC motor generator. This is a small set, prop diameter is 7'. I tried many motors before finding one that would work. What you need is a motor that is rated at low RPM and higher amperage. The bigger cased motors usually have bigger windings and that is what's needed. Old school Ohio Electric hard drive motors fit this description but are becoming increasingly hard to find.

    I've experimented with higher RPM motors of various sizes and different gear reduction but those have to much torque to be used at typical wind speeds, mounting heights, and with small diameter props.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #9
    Re: trying to test a motor
    westend wrote: »
    It would be helpful if you list the items off the rating plate of the motor,i.e. AC, DC, RPM, Load A, V, HP.
    Welcome to the Forum, westend.
    If you look far enough back in the thread you will realize that the subject is a computer fan, not a motor converted to a generator for wind turbine. :-)
    SMA SB 3000, old BP panels.
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  • westend
    westend Solar Expert Posts: 46 ✭
    #10
    Re: trying to test a motor
    inetdog wrote: »
    Welcome to the Forum, westend.
    If you look far enough back in the thread you will realize that the subject is a computer fan, not a motor converted to a generator for wind turbine. :-)
    When he put "other motor" in his last post, I thought we were back to the treadmill motor. Sorry..
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