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[How do I?] Switching Question

Discussion in 'ELECTRICAL ISSUES - POWER YOUR MACHINES & SHOP' started by jbolt, Mar 23, 2017.

  1. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    I want to switch the motor of an electric impact wrench with a momentary ON-OFF-ON toggle switch. Pos A = ON/FWD, Pos B = ON/REV.

    I had originally thought I could use a DPDT switch but after tracing out the ON-OFF and FWD/REV it does not look like I can do that.

    The motor coil has four leads. Two are the AC Line & Neutral and the other two are to the brushes. The brushes are switched through a FWD/REV switch.

    Here is a wiring diagram of the motor & switching.

    Motor Wiring.png

    Is there a way to make a DPDT switch work or could a 3PDT switch be used and just switch the LINE side of the AC in?
     
  2. Bob Korves

    Bob Korves H-M Supporter - Premium Content H-M Supporter-Premium

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    Not sure, but you might need the equivalent of a drum switch.
     
  3. RJSakowski

    RJSakowski H-M Supporter - Premium Content H-M Supporter-Premium

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    If it you have a series wound motor, the DPDT center off switch should work. In the center off position, the circuit will be broken. In that case, the line and neutral would just be connected through to R1 and R2.

    If you still have current flowing, a 3PDT switch should work. If you connect the line to the center terminal of one pole and connect the other two terminals of that pole to the motor R1 terminal and R2 terminal.

    The down side of either of these is that the wiring is live when the switch is off rather than terminating at your on/off switch as it does now but that shouldn't be an issue as long as the tool is double insulated or grounded.
     
  4. jbolt

    jbolt United States Active User H-M Supporter-Premium

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    Ah I see now. With a DPDT switch the circuit is broken between the coils and the brushes.

    The manual says it is double insulated. I will wire and test with caution.
     
    RJSakowski likes this.

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