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Thread: 220/240 volt advantages?

  1. #1
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    220/240 volt advantages?

    Years ago, I ran a 220V circuit to power my tablesaw. I recently acquired a lathe that also requires 220V. While I'm at it, is it worthwhile to add 220V drops to other machines that can run on that voltage (jointer, bandsaw, etc.)? For home shop motors that can run on either 110 or 220, what are the advantages of higher voltage? Cooler running? Greater longevity?
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  2. #2
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    Runs cooler because it uses less amperage which also costs you less money.

    I think 220v is worth it. I was given an old version of a Grizzly dust collector that ran 220v ONLY. It has been replaced by a new design that runs either 110v or 220v. The sacrifice is that the new unit is capped at 12 amps @ 110v / 1.5 HP while my old one is capped at 2 HP because it can take a higher amperage @ 220v and Grizzly didn't have to worry about making the motor compatible w/ 15 amp 110v.

    You probably have a few 20 amp 110v circuits in your house, but that's as high as I've personally seen. Where as 220v are commonly wired for pretty high amperages (high HP).

    3 phase is even better. I just picked up a 3 (three) amp 3 HP 480 v dust collector. Pretty awesome.

  3. #3
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    In the context of motors, it mainly comes down to the ability to do work at a given current. With 240V there is a higher voltage potential and to do the same work it requires half the current. In a residential context you can get a very powerful 240V motor pulling say 12A and generating 3 horse power. In contrast to do that same thing at 120V you're needing double that current. Wiring, breakers, etc. all need to be setup to protect the cabling delivering the power to the machine. So, manufacturers will generally half the horse power instead so it fits better in the application because >20A breakers and wiring at 120V is exceedingly rare. I preplanned by shop setup and I only went 8 120V 20A services as there really aren't a lot of 120V tools that pull more than 15A.

    By having 240V available now YOU have the option to decide what kind of power you need at a given machine. Maybe 120V is sufficient, maybe you need more and now you have the option.

    In terms of reliability, cooler, etc. it's largely splitting hairs assuming it's a quality tool built to purpose. 240V will give you a bit more efficiency, but often you're also getting more power so heat/power really varies by machine and application.
    Last edited by Michael Burnside; 03-31-2023 at 2:22 PM.

  4. #4
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    In the context of woodworking, 240v machines typically have higher horsepower motors and higher capacities for work as a result. So having multiple 240v outlets can allow you to have the opportunity leverage the more capable machines should you want or need them. While you can have all the machines you can only use one at a time on the same circuit, if you also put in a 240v dust collector, that should have a separate circuit from the other machines. The only other reason to have additional 240v circuits in most one-person shops is for special needs, such as a CNC machine that requires a four wire circuit, a Mini SPlit HVAC system, a welder that requires a higher amperage circuits, etc. For the shared machine circuit, set that up so it able to handle the amperage of the highest rated tool (typically 30 amp in a woodworking shop for a big saw, J/P, etc) and standardize your receptacle/plugs to that higher amperage for flexibility.
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  5. #5
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    For a given motor Power is power no matter the voltage. There is no significant advantage of running a motor of a given horsepower at 240 volts versus 120. 240 Volts does allow you to use smaller gauge wire which will save some cost on wire but the 240 volt breakers, plugs and receptacles will cost more.

    Here is a link to more discussion of this.
    Lee Schierer
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  6. #6
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    Runs cooler because it uses less amperage.

    Electric cost won't change. (120V @ 15A = 1.8kW, 240V @ 7.5A = 1.8kW)

    Gauge wire required is smaller, thus less expensive for the same motor. Or for the same expense (installation of 12g wire) you can run high HP motor. On a 120V 20A breaker with 12g wire the highest HP motor is 2, whereas a 3HP motor can be run on the same wire using 240V.

    Spin up time will be less, but not by an amount that a human would care about.

  7. #7
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    Quote Originally Posted by Lee Schierer View Post
    For a given motor Power is power no matter the voltage. There is no significant advantage of running a motor of a given horsepower at 240 volts versus 120. 240 Volts does allow you to use smaller gauge wire which will save some cost on wire but the 240 volt breakers, plugs and receptacles will cost more.

    Here is a link to more discussion of this.
    Quote Originally Posted by Anthony Whitesell View Post
    Runs cooler because it uses less amperage.

    Electric cost won't change. (120V @ 15A = 1.8kW, 240V @ 7.5A = 1.8kW)

    Gauge wire required is smaller, thus less expensive for the same motor. Or for the same expense (installation of 12g wire) you can run high HP motor. On a 120V 20A breaker with 12g wire the highest HP motor is 2, whereas a 3HP motor can be run on the same wire using 240V.

    Spin up time will be less, but not by an amount that a human would care about.
    I agree!

    When I built my shop, I put 240v.a.c. boxes evenly dispersed around the perimeter walls so in the future I could place higher horsepower equipment where I wanted. Then I, also, wired them with 12 gauge wire so I could put heavier duty motors near those outlets as I deemed necessary. I put one in the wall between the walkin-door IIRC wired with 10 gauge and the insulated garage door so if I decided I needed use a welder it was handy to put the welder outside when welding.
    Last edited by Ken Fitzgerald; 03-31-2023 at 11:19 PM.
    Ken

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  8. #8
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    Your motor will run more efficiently, but, yes the practical side of things... you'll save pennies.

    My point still stands: 220v gives you more freedom for bigger machines. If you want bigger and better machines that consume more HP, you will have to use 220v. I don't see a woodworking tool company building a 110v motor that consumes more than 15 amps. But, maybe they exist. IDK. I haven't looked. Seems oddball to me.

    Edit to add:

    To remove confusion. When we are buying electricity from the utility company they don't care about your motor OUTPUT power. They care about the INPUT power. The INPUT power = OUTPUT power + X power (real life inefficiency of your motor). X power is less for higher voltages, hence you buy less power from the utility company for a given OUTPUT power.

    Maybe that difference is small and/or the motor is turned on so infrequently that practically speaking it makes no difference, but I feel like there is some confusion above regarding this point.
    Last edited by andrew whicker; 03-31-2023 at 5:37 PM.

  9. #9
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    Many more options for VFDs to give you three phase power and variable speed where that matters. You can often go down a step in wire gauge (or up a step in amperage without rewiring).

    I'm not sure what advantages, if any, there are for 120V power. Much of the rest of the world gets along fine without it.

    I wired all the outlets in my shop except for the dedicated single machine 240V circuits as MWBCs (multiwire branch circuits) giving me both 120 and 240 V options at every drop as well as ability to plug two 120V larger loads in at a single drop. Yes, a bit of extra wire cost in theory, but it only take one reorganization of the shop to recoup what was, at the time, a very small difference in price between 12-2 and 12-3 cable.

  10. #10
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    What Lee said. There is no difference inside the motor.

    John

  11. #11
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    If you want bigger and better machines that consume more HP, you will have to use 220v. I don't see a woodworking tool company building a 110v motor that consumes more than 15 amps.
    Since the largest 120V outlet is 20A, the biggest motor that can run on it is 16A. That's why you'll never see a larger 120V motor.

  12. #12
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    Quote Originally Posted by Mike Stelts View Post
    Since the largest 120V outlet is 20A, the biggest motor that can run on it is 16A. That's why you'll never see a larger 120V motor.
    I only did a quick look.

    Grizzly G0513X2 Bandsaw "Motor: 2 HP, 110V/220V (prewired 220V), single-phase, 19A/9.5A"

    BALDOR 1425RPM 184T TEFC 1PH MOTOR L3609T-50 110V 25A/220V 12.5A

    Not that I would want to run either of those motors on 120V. But there are motors that can be wired on 120V that require more than 20A service.
    Last edited by Anthony Whitesell; 03-31-2023 at 10:21 PM.

  13. #13
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    Quote Originally Posted by Anthony Whitesell View Post
    I only did a quick look.

    Grizzly G0513X2 Bandsaw "Motor: 2 HP, 110V/220V (prewired 220V), single-phase, 19A/9.5A"

    BALDOR 1425RPM 184T TEFC 1PH MOTOR L3609T-50 110V 25A/220V 12.5A

    Not that I would want to run either of those motors on 120V. But there are motors that can be wired on 120V that require more than 20A service.
    Sorry, I didn't finish my point earlier... Nobody would sell these motors wired for 120V, because they wouldn't pass UL. If they exceed 16A (80% of 20A), they can't be sold for 120V. If one decides to rewire for 120V, it's at their risk, not the manufacturer's. The practical limit is about 1.75 Hp; e.g. SawStop and Powermatic offer 1.75Hp motors.

  14. #14
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    Quote Originally Posted by Mike Stelts View Post
    Sorry, I didn't finish my point earlier... Nobody would sell these motors wired for 120V, because they wouldn't pass UL. If they exceed 16A (80% of 20A), they can't be sold for 120V. If one decides to rewire for 120V, it's at their risk, not the manufacturer's. The practical limit is about 1.75 Hp; e.g. SawStop and Powermatic offer 1.75Hp motors.
    If the motor has the option to be wired for 120V, independent of who does the wiring, and is UL listed then it is UL listed in both 120V and 240V configurations. The owner needs to know they need an L5-30 30A 120V outlet wired with 10g wire if they intend to run the motor on 120V.

  15. #15
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    Another way of saying what others have said: to get the same HP as a 220V/20A circuit from 110V, you would need 110V/40A, which just isn’t a thing. Your limit for 110V (or 115V) is usually 15A but could be higher on a 20A dedicated circuit. Although vacuums advertise 6 “peak” horsepower, for example, that’s just a burst at startup. The real horsepower maximum you will get from 110V is around 3.5HP.

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