Need help wiring a motor switch

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Discussion Overview

The discussion revolves around wiring a motor switch for a new motor installation on a Logan lathe. Participants explore the specifics of connecting a reversing switch and ensuring proper electrical connections, including considerations for voltage and grounding.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes the existing wiring of the old motor and seeks assistance with the new motor's wiring, specifically regarding the reversing switch.
  • Another participant suggests identifying the supply voltage, asking if it is closer to 115V or 230V.
  • The original poster clarifies that both 120V and 220V are available, but the old motor operated at 120V.
  • A participant proposes connecting the neutral of the 120V supply to T5 of the new motor, indicating that the reversing switch will handle the T6-T8 swap.
  • Another participant confirms the connection of Line1 to T5 and suggests following a specific wiring diagram for the remaining connections.
  • The original poster reports successful testing of the wiring setup, noting adjustments made to terminal connections for correct motor rotation.
  • A participant emphasizes the importance of connecting the protective earth to both the motor casing and lathe chassis, while humorously acknowledging a previous mistake regarding rotation direction.
  • Another participant agrees on the grounding issue and reflects on the learning experience regarding motor rotation direction.
  • The original poster concludes that the new motor and drum switch are functioning properly after installation.

Areas of Agreement / Disagreement

Participants generally agree on the wiring approach and the importance of grounding, but there are variations in specific wiring details and the interpretation of motor rotation direction.

Contextual Notes

The discussion includes assumptions about the wiring configuration and the specific motor model, which may not be universally applicable. There are also references to personal experiences that may influence the advice given.

Who May Find This Useful

Individuals working on motor installations, particularly in lathe applications, as well as those interested in electrical wiring for machinery.

gmax137
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I'm replacing the motor on my old Logan lathe. The old motor was pretty simple, it had four wires; two to run and two for the starting coil. I can't seem to figure out how to wire up the reversing switch for the new motor. Here's the plate on the new motor.
motor_plate_crop.jpg


The drum switch I have is like this:

drum_sw2.jpg

Any help appreciated.
 
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gmax137 said:
Any help appreciated.
Start by identifying your supply voltage.
Is it closer to 115V or 230V ?
 
Baluncore said:
Start by identifying your supply voltage.
Is it closer to 115V or 230V ?
Oh, sorry! I have both 120 & 220 available within a few feet of the lathe. The motor I'm replacing was 120V.

Thanks @Baluncore

EDIT: this is in the US, single phase.
 
Last edited:
I think you will have to connect the neutral of the 120V supply, to T5 of the new motor, as it cannot be switched, since the reversing switch is needed for the T6-T8 swap.
Connect all others into the two bundles, as shown for the 115V motor diagram, except the T6 swap with T8, that will be done by the reversing switch. I'm busy, so the details are not specified yet.
 
Connect Line1 to T5 then others as shown here.
drum_switch.jpg
 
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Thank you @Baluncore ! I need to stare at this for a while but it seems you are right on.
 
Hello again, @Baluncore . I did a test mockup on my bench using your suggested wiring. It worked fine. I had to put T6 to terminal 3 and T8 to terminal 4 to get the correct rotation in 'forward.' Thanks so much for your help! Next step is getting the motor & switch back into the lathe so I can get the chips flying again.

motor_mockup.jpg
 
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I see you have the protective earth on the switch. Please make sure it also connects to the motor casing and the lathe chassis.

My apologies for getting the rotation backwards. I was multitasking in the Southern Hemisphere, and so was hanging upside down by my feet.

Perfection is the enemy of progress. I maximise progress.
 
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Plus 1 on the grounding/earth.

No apology please -- forward for the lathe could be CW or CCW depending on which way the motor gets mounted in any particular machine. At least I knew which wires to swap. I learned quite a bit in the last week.
 
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  • #10
After a few delays, the new motor and drum switch are in and working fine. Thanks again @Baluncore !

EDIT: fixed photo orientation


logan_motor.jpg
 
Last edited:
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