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How to re-wire an old AC drill to a new switch

Discussion in 'General Electronics Discussion' started by animartis, Jul 30, 2013.

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  1. animartis

    animartis

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    Jul 30, 2013
    Hello all,

    I am repurposing a drill motor and need some help rewiring. Here is how it is currently wired. The hot and neutral come into the trigger switch. There are six leads out of the trigger switch: Two black and two white to the motor and a blue to each magnet. I would like to rewire this to a three way toggle switch (so I can change direction) and, if possible, be able to adjust the speed. Any assistance would be greatly appreciated.

    Thanks!
     

    Attached Files:

  2. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    This is lmost certainly a series wound (universal) motor. In order to change direction, the wires to the field winding or the brushes must be reversed. A relay could do this.

    A lamp dimmer could be used to vary the speed but may be jerky at low speeds.

    Some of the wires may be to capacitors to reduce interference getting back into the mains. You should be able to find the capacitors.
     
  3. animartis

    animartis

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    0
    Jul 30, 2013
    Thank you for the quick response, it really helped me along. I know I may be out of my element, but I wanted to figure out what the blue wire going to the brush provides. Is it a HOT wire?

    Since there are 3 pairs of the same color wires, i'm assuming that the Blue (to brush) and Black (to motor) are HOT and the white is NEUTRAL. Then the Reverse switch on the drill just changes the path of the electricity to the other pair.

    Anyway, I've attached a picture of my proposed wiring. Could someone take a look and see if it is appropriate?

    Thank you!
     

    Attached Files:

  4. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    Do not assume anything.

    Trace out the original circuit and post it here. Use the terms 'brush' and 'field' rather than 'motor'. There will be some interference suppression capacitors somewhere.

    You should not use two relays giving opposite output, that is a recipe for disaster. You can manage without any relays, just use a two pole two way switch to change direction.
     
  5. animartis

    animartis

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    Jul 30, 2013
    Thank you duke37, I'm learning more and more every day about this!

    Here is current wiring diagram. After tracing out the path, here is what I've found. Referencing the attached picture, the SWITCH changes the path to the brushes. One pole send it to AB and CD, where the other pole sends to AC and BD.

    Also, I do not see any interference suppression capacitors in the drill, unless they are build into one of the components and I cannot see them.

    I realize I'm a bit out of my element here but am determined, so thank you for your patience!

    Cheers
     

    Attached Files:

  6. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    I am out of my depth here also !

    It looks as if you will need to keep the drill case to hold the motor bearings. If so, can the change direction switch be used in the drill?

    If you wish to use an external direction switch, then an intermediate (crossover) switch as used for a third switch in a two way lighting circuit can be used, Wire this in place of the internal switch, you will need four wires to the drill.

    To vary speed, a triac light dimmer can be used. I have tried these and some work better than others. A lamp in parallel to the drill may make it behave better.

    To test it, you can use a low voltage, say 12V AC or DC can be used.

    I doubt if you have the correct crimping tools to make a good job of connection modifications and bad connections are liable to lead to fires.
     
  7. animartis

    animartis

    5
    0
    Jul 30, 2013
    It sounds like you're thinking I should run this all AC, but I was wondering if I could control it via DC, say with a relay. The reason I ask is because I eventually would like to move this set up (stage II) to an arduino or Raspberry Pi for automation and control. I've used DC to AC solid state relays in the past, but never for something like this where there are multiple leads.
     
  8. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    I do not think that solid state relays would be suitable in case there is a glitch enabling forward and reverse at the same time. You can use a two pole change over mechanical relay to eliminate this possibility.

    I would not know how to control speed from a micro.
     
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