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Light Dimmer Swith Trouble

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  • 28-11-2009 2:39pm
    #1
    Schizems
    Closed Accounts Posts: 2 ✭


    i have a small 12v Electric motor i'm trying to set it up as a record player motor, and i have a 12v 9v 7v 5v power supplys but i am trying to use a set of 3 double a's. my question is, is it possible to rig up a dimmer switch to this?


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    #2
    DublinDilbert
    Registered Users Posts: 5,369 ✭✭✭DublinDilbert


    Schizems wrote: »
    i have a small 12v Electric motor i'm trying to set it up as a record player motor, and i have a 12v 9v 7v 5v power supplys but i am trying to use a set of 3 double a's. my question is, is it possible to rig up a dimmer switch to this?

    The quick answer is no... a dimmer switch just works on AC, where as you have a DC motor and the batteries are DC.

    Your AA batteries are 1.5V each, so the 3 of them in series will give you 4.5V, which is very little to run your 12V motor. I would advise you to get more batteries or a lower voltage motor.


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    #3
    Schizems
    Closed Accounts Posts: 2 ✭Schizems


    Thnx for the help, after some searching and a little learning, i figured out that i need a Potentiometer, and as far as the low voltage i just need a little only need to push the record to 33 rpms


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    #4
    Rev. BlueJeans
    Closed Accounts Posts: 600 ✭✭✭Rev. BlueJeans


    How are you gearing it to the turntable?

    The TT alone will need considerable mass to overcome any fluctuations in the torque (which will be in short supply anyway with an underpowered motor.

    Most pots too won't cope with the current required. Far easier to pick up a turntable on ebay or somewhere tbh.


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    #5
    10-10-20
    Registered Users Posts: 6,819 ✭✭✭10-10-20


    You can't use a potentimeter to control a motor directly. They are only rated for a couple of mili-amps, so it would melt the resistive material in an instant.
    You'd need a kit to do it.
    http://www.quasarelectronics.com/motor-controllers-drivers.htm

    Have a look at the velleman kits in Maplin. I think they have one.


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    #6
    DublinDilbert
    Registered Users Posts: 5,369 ✭✭✭DublinDilbert


    Rev. BlueJeans wrote: »
    How are you gearing it to the turntable?

    The TT alone will need considerable mass to overcome any fluctuations in the torque (which will be in short supply anyway with an underpowered motor.

    Most pots too won't cope with the current required. Far easier to pick up a turntable on ebay or somewhere tbh.

    +1

    You need to gear down your motor to get it to the 33rpm, rather than just reduce the voltage.

    When you gear down, you'll increase the available torque / reduce the motor current.


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