A recent post by notrix brought up a question I have been pondering. I plan to convert my table saw and planer from 110 to 220. I plan to use the spot in the breaker panel that is wired to the dryer outlet (we have natural gas now) and “rewire” a new circuit to the shop (about 20 feet from the panel). The main reason is amp usage in my breaker panel, but that is not relevant to the question. Both motors are “dual voltage”.
This is my question. Will I need to purchase a new “on / off” switch for these machines? If so, should I go through the manufacturer, or a “third party” company. I assume if I need to change the switch, that would also involve changing the wires between the switch and the motor. Both machines are a Jet.
I plan to use 12 ga. wire with a 20 amp breaker. The 12 ga. wire will run to an outlet, and run the power cord to that.Am I thinking correctly?
Replies
I don't want to speak to your equipment, but I converted my Delta TS to 220 with no trouble, and without changing anything on the saw but the plug (well, other than changing the motor taps, of course). Never touched the switch.
I have a sub panel in my "shop" - the TS is on a 20 Amp breaker with, IIRC, 10Ga romex.
"Shop" is in quotes cuz the place is closer to the pits than a proper shop.
I agree with Ed; if the machine motor is dual voltage, you don't have to change the switch, only the plug (t0 accommodate a 220v outlet).
I assume you know you must also change some wires around in the motor itself. This is easy, since they always have a diagram (usually inside the housing) that will tell you what wire goes where.
I am not an electrician, but I think 12 ga wire would work fine; but like Ed, I too ran a 10 ga wire just to be sure.
Sorry to disagree with the last couple of posts but, if your saw was sold as a 110V machine, then it probably has a single pole switch. If you are re configuring it to 220V, then you will have two hot leads instead of one. A single pole switch will leave one hot lead to the motor connected all the time. Not a particularly safe situation.Although I'm not an electrician either, I do know that a double pole switch is need for 220VAC.Tom
You are certainly right about any machine that was intended only for 110v operation.I was referring to machines with dual voltage motors -- such as the Unisaw. If the issue about the switch is not addressed in the manual, it would be prudent to check with the service center for the manufacturer of that machine.
The switch is a very important part of the system. If the saw came with a 120V setup and a regular switch you may be okay doing the plug and wire swap. If the switch is magnetic you need to rewire the switch also and install another heater element to run at a diffrent voltage. My DJ20 cme 220 and I needed a new heater for the swith to go down to 120V. Also check delta's site, they have tons of manuals and faqs online.Good Luck
Aren't all induction start motors dual voltage? All of them that I've seen are, but I haven't seen everything yet. When I changed my old Jet contractor's saw from 110V to 220V, I had to replace the switch. The original was a simple SPST togggle.Tom
Only small induction motors are dual voltage. 3 HP and over are never 120V -- too much current.
The equipment manufacturer should be able to tell you what switch re-wiring or replacement is necessary.
It is an older model Jet contractor's saw. The switch has two wires, one white and one black, leading from the motor to the switch. The same configuration, one white and one black, leads from the switch to the plug. A green ground wire runs from each pair of wires to a metal plate which mounts the switch to the rip fence rail.
If both of the black wires and both of the white wires are actually going to terminals on the switch, then the existing switch can be used for the higher voltage hook up since both wires are being switched.
John W.
Personally, in 20 years of selling, assembling and using woodworking equipment, I dont' think I have ever seen a tool that had a dual voltage motor that didn't have a double pole switch supplied as standard equipment. A manufacturer would be wide open for a lawsuit if they supplied a single pole switch.Howie.........
Edited 1/17/2005 10:01 pm ET by Howie
You may have to change the switch. In a 220 volt appliance both legs are hot. Therefore you need a switch which opens both legs. A switch for 110 would only open one leg. Unless you happen to have a switch which opens both legs, you'll need a new one.
Thanks, all for your responses. I realize I need to change the wiring in the motor, and that is spelled out in a diagram in the manual. The switch issue was never addressed. I'll take a look at the switch that is on there now.Thanks again for your input.
It would be helpful if you would tell which saw you have and what kind of switch is on it.
If you have a magnetic starter, it most likely breaks both leads, but you should also look at the coil and see how it is wired, and what voltage it requires.
If it is wired into the leg which was the neutral, but is now the second hot, you may fry it.
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