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  • Switch to 230 volts for saw?

    In "The Table Saw Book" by Kelly Mehler, he states (page 112) that, if possible, it is an advantage to wire a dual voltage saw to 230 volts (from 115), resulting in fewer circuit overloads and longer motor life.

    Never heard this before but is there a benefit to this switch?

  • #2
    Re: Switch to 230 volts for saw?

    This is an often debated subject and much misinformation tends to abound.....I'm no expert, so I hope to avoid leading you astray. The switch to 230v shouldn't hurt a thing, and there's often benefit. The benefits are the part that are often contested. With 115v circuits, you get full current through one leg of the wiring. In 230v, it's split between both legs meaning you can run lower gauge wire to cut costs. Theoretically, the motor is seeing the same current draw regardless...the two coils are in paralllel for one, and in series the other. You're particular wiring arrangement may throw a few curves into the equation that we can't predict.

    You'll get more noticeable improvements "IF" you're current 115v circuit isn't quite capable of delivering full power due to voltage losses. If you're wiring is up to code and capable, some will argue that there's no benefit of switching, but if I understand it correctly, there's less chance of voltage sag from a 230v circuit than a 115v circuit....especially on start up. Voltage loss results in heat which puts more strain on the motor.

    I've switched my last two saws to 230v. I noticed very little difference on the first one, but no harm done. But I noticed considerable difference on my current saw. It must have had just enough additional draw to tax my 115v circuit a bit. I'm for swithcing if 230v is easily available and your current wiring is not optimum, but if you're current circuit is a dedicated 20 amp line that's up to snuff, I wouldn't be eager to sink several hundred dollars into the conversion.


    p.s. One of the funniest stories I've read on these forums, is what I believe to be true story that occurred to a Ridgid saw owner who I also believe frequents this board. A guy spotted a used Ridgid saw for sale in the local paper for $450, and went to see it. After looking it over for a bit, he spent several minutes trying to talk the guy down to $400 and explained what he thought was wrong with the saw and why he didn't think it was worth the full asking price. After a while the seller finally agreed to $400. The would be purchaser asked who to make the check out to...the seller answered "Kelly Mehler". It turns out the saw being sold was the one of the front cover is his book!
    Last edited by hewood; 05-09-2007, 05:49 AM.

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    • #3
      Re: Switch to 230 volts for saw?

      just a little more info.

      if the saw draws 15 amps at `120 volts. then it would draw 7.5 amps at 240 volts. it would still consume 7.5 amps on each leg of the 240 volt circuit. this is of course without a load on the motor.

      i converted a pool pump 2 hp. to 240 volts. my electric bill stayed the same. the pool pump motor doesn't strain as hard and the 12 gauge wire is much happier.

      rick.
      phoebe it is

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      • #4
        Re: Switch to 230 volts for saw?

        The electrical usage is the same, but the voltage drop is less, as less amps are pulled through each wire, and on the switch, there is less amps which normally is less arcing,

        and since the voltage drop is less there is less heat build up,

        It helps balance the loads in the house, normally there is less brown down (voltage dip) in you home, do to the start loads, (motors depending on type, Can draw up to 5 times the run load, normally about 3 times, the run load, and that is where the voltage comes in),

        small motors under 1 horse power, you normally will not see much difference, but when you start to get into larger motors, over 1 hp, IN a home shop, the start up will be quicker and less voltage drops, and depending on breakers, less snapping of them. most breakers can take momentally over loads, for motor starting.

        but when you go to 220/240 volts, the amps drop and usually it helps many of the problems one can have on a 110/120 volt circuit,

        A lot jsut depends on the quality of the wiring and size of it, and if your dealing with 15 amp breakers and 14 gage wire, or 20amp and 12 gage wire,
        Push sticks/blocks Save Fingers
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        • #5
          Re: Switch to 230 volts for saw?

          If you have 220-240 Volt power near where you use your tools, I would switch your saw over to 220-240 Volts. You'll need the correct receptacle and plug for the power cord and be sure you have a double pole switch to break both hot sides. If the switchover is going to cost big money and your table saw runs fine as is, then I would leave well enough alone.

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          • #6
            Re: Switch to 230 volts for saw?

            This saw will be at a new home and I had a 240v receptacle installed for an arc welder. I was planning on using that 3 prong receptacle.

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            • #7
              Re: Switch to 230 volts for saw?

              Originally posted by marchboom View Post
              This saw will be at a new home and I had a 240v receptacle installed for an arc welder. I was planning on using that 3 prong receptacle.
              not a good idea. the arc welder probably has a 50 amp double breaker. the table saw would require a 15 or 20 amp double breaker. unless you downsize the breakers and swap the outlet to a 20 amp configuration, it's not safe. you can keep the heavier 6 gauge wire though. you would probably have to pigtail the 20 amp outlet to the 6 gauge wire.

              what ever happened to all the sparkies on this forum

              are they all at the donut shop

              rick.
              phoebe it is

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              • #8
                Re: Switch to 230 volts for saw?

                [quote=PLUMBER RICK;78204]not a good idea. the arc welder probably has a 50 amp double breaker. the table saw would require a 15 or 20 amp double breaker. unless you downsize the breakers and swap the outlet to a 20 amp configuration, it's not safe. you can keep the heavier 6 gauge wire though. you would probably have to pigtail the 20 amp outlet to the 6 gauge wire.


                If you have a welder outlet in your shop, it is probably 50 Amps and too much for the saw. You can do a couple of things to utilize that circuit however for your saw. You can go into the electrical box and connect a small 2 circuit breaker box to the line, install a dual 20A breaker in it and come off to another electrical box with the correct recpt. for the saw. Or you can get a 50Amp plug that fist the welder outlet, run a J cord to the same 2 circuit breaker box and hard wire the saw to the breaker box. When you want ot use the saw simply plug that set up inot the wekder outlet, now you are protected at the lower value of 20 amps. By the way, a saw or any device that is changed from 115 to 230 or 120 to 240 draws HALF the current. The POWER consumption is the same, but the current is HALF. The voltage is 2 times. Things run better on 240, thats a fact. Lou

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                • #9
                  Re: Switch to 230 volts for saw?

                  If you want to do this the right way and don't mind some $$$, I would use the welder line to feed a small sub-panel in your workshop. Go to your main load center (breaker panel) and find the breaker for the welder. Also, are there other breakers for circuits in your shop? My idea would be to power only the 240 Volt motors out of the sub-panel if there are already 120 Volt circuits to your shop. You could have a 2 pole 40 or 50 Amp breaker for the welder and another 2 pole 20 Amp breaker for your table saw. That one would get connected to a 6-20 (20A 250V grounding) receptacle. If you know an electrician that does some side work have him/her come by and look things over. You have choices, but you don't want to have a 50 Amp breaker for a 15 or 20 Amp circuit.

                  Can you take a few pictures or maybe make up a listing of what circuits are in your shop?

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                  • #10
                    Re: Switch to 230 volts for saw?

                    Thanks to all who answered my question and, most importantly, brought up issues that I hadn't thought of. Sounds like I'll just keep the saw wired for 120V for a while and see how much I use it. If I use it a lot more, then maybe I'll switch it over to 240V.

                    Thanks again.

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                    • #11
                      Re: Switch to 230 volts for saw?

                      Originally posted by hewood View Post
                      [SIZE="2"]...Theoretically, the motor is seeing the same current draw regardless...
                      It isn't "splitting" up the current that lowers the amperage. It is the higher voltage which requires less current to produce the same power. Power equals voltage times current. When you double your voltage you can half your current and still deliver the same power.

                      Additionally, motors are more efficient at higher voltages. At startup, a motor will draw much more current...same is true during high loads. The 220 volt setup has twice the power capacity to deliver at these times.

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