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Need help Converting a variable Speed 12v drill to corded drill - 3rd wire?

Discussion in 'Sensors and Actuators' started by Clayt, May 8, 2018.

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  1. Clayt

    Clayt

    3
    0
    May 8, 2018
    I need to convert this 12V Ridgid cordless drill to a corded 12v DC drill to use off my boat's battery supply.

    I do not have the original drill battery, only the drill.

    After dissembling the drill, there are 3 wires going to the switch from the battery. a RED, BLACK, AND WHITE. There are only 2 wires (red, black) leading from the switch to the motor.

    I put 12V directly to the motor to verify the motor operates...it does.

    However, when I hook 12V to the red & black wires that lead into the switch, the motor does NOT operate.

    I have also tried to hook the white wire to both the + and - side of the circuit with no success.

    Can anyone help me with this? What does the white wire do? I cannot find any info online.

    The final result will need to be variable speed so direct-wiring the motor is not an option.

    See attached pics.


    Thanks in advance!
     

    Attached Files:

  2. kellys_eye

    kellys_eye

    4,276
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    Jun 25, 2010
    I don't think the 'switch' you refer to is a switch - it's a variable speed controller that may well be dud hence it not working as you expect.
     
  3. Clayt

    Clayt

    3
    0
    May 8, 2018
    Yes, you are correct. It is not a "switch" but I am using that term to describe the "variable speed controller". I do not believe it is a dud as the whole unit is brand new.
     
  4. kellys_eye

    kellys_eye

    4,276
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    Jun 25, 2010
    in which case you have the rest of the machine so should know where the wire came from???

    It could be current sensing, temperature sensing, voltage tap (from a separate part of the battery) or even something more 'sinister' like a device to stop you using the drill with anything other than the genuine battery......

    I'd find an after-market 12V drill trigger and use that in its place.
     
  5. Clayt

    Clayt

    3
    0
    May 8, 2018
    I dont have the rest of it. The 3 wires were soldered to a little plastic plate with 3 metal contact pads that all make contact with the battery when it is inserted.

    I was afraid it might be some sort of temperature sensor of some sort!

    Any ideas on how to get around this or "hot wire" it? This is a small project with a small budget....

    Thanks
     
  6. Bluejets

    Bluejets

    3,995
    826
    Oct 5, 2014
    Two wire variable speed switches are available from Ebay for around $5.00.
    I used one to replace a dud switch in an old 7.2v makita as the original replacement speed switch was over $70.00.
    Working great for last 12 months.
     
  7. 12vdc

    12vdc

    46
    9
    Apr 13, 2011
    I am the master of disaster when it comes to corded cordless tools.
    I have converted many to muscle build versions by adding UPS 12 v 7ah SLA batteries.

    as stated some drills had a 2 speed motor by using a center tap of the battery. (craftsman 7.2v drill)
    I was learning and accidentally reversed polarity on the variable speed switch and got smoke. upon use of proper polarity it was dead.

    can you disassemble the switch?
     
  8. Bluejets

    Bluejets

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    826
    Oct 5, 2014
  9. kellys_eye

    kellys_eye

    4,276
    1,146
    Jun 25, 2010
    Not sure why the controller didn't work in the first place but ^this^ could have caused permanent damage anyway....
     
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