1 phase v 3 phase powermatic tablesaw

Nov 18, 2007 10 Replies

I am looking at purchasing the Powermatic 2000 tablesaw, but I am not sure of the difference between 1 phase and 3 phase. The descriptions both say they are 5 HP. My shop is currently wired with 240v, 20 amp and 30 amp plugs.



Thanks.



Trent


Typical residential power in the USA is single phase. If your shop is in a commercial building you may have three phase. Do you have any 4 pole outlets mounted anywhere? If you do you probably have three phase power. Greg

if you don't know what 3 phase power is I'd say it's a safe bet you don't have any. get the single phase machine.

If you don't have three phase power you can't use a three phase tool (at least not without going to a lot of extra work). If you don't know whether you have three phase then it's almost certain that you don't.

You are looking for a receptacle that looks something like this in the building to indicate you have 3 phase power -

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you do not have any outlets that take a 4 pin cord, you probably do not have 3 phase power available. If you have overhead wiring - count the number of wires that run from the pole to the building - if it is not at least 3 coated wires (typically black) then you do not have 3 phase power. If you are in a residential neighborhood you probably do not have 3 phase power.

My utility charges by the mile from the end of the feeder to the home for 3 phase power to be installed - believe me you do not want to know the price.

If you need 3 phase power there are motor-generator sets available that will convert 1 phase to 3 phase. A good place to look (not to buy - I have never worked with them) at the specs for phase converter systems is:

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The two legs of a residential system are 180 degrees out of phase, the three legs of a three-phase system are 120 degrees out of phase.

A "208V" electric heater runs on the same voltage as a "240V" electric stove. If you think otherwise, show us how the two are wired differently.

You're getting 3 additional wires to get 3-phase.

On Sat, 17 Nov 2007 23:21:28 -0600, "Greg O"

Actually, you typically have 2 phase power into residence. 120 V on two legs of a 3 phase system. This allows you to run phase to phase (208V) like on some electric heaters, or 240V (120 x2) for an electric stove. Depending on location, you can get the third wire to give you 3 phase, but be prepared to pay the big bucks.

If the shop is 'residential' there will likely only be 2 phase power and you can confirm this my looking at how many wires enter the mast just before the meter on the building. 3 wires is 2 phase (2 power-one common)

Pete

Around here residential is single phase. Line to line is 240 volt, line to neutral is 120 volt. I have never heard of what you describe in a residential setting. I question if you are certain about what you describe. How do you get 208, and 240 out of one service, never seen it without additional transformers. 208 volt 3 phase will get you 120 to neutral. We see it all the time in commercial buildings. We used see some 240 3 phase commercially, but it seems to have been replaced with 208 3 phase. Greg

On Sat, 17 Nov 2007 23:21:28 -0600, "Greg O"

Single phase, center tapped.

Single phase power. Two hot legs from a transformer and a center tap which you tie to ground in your panel.

Um, no. In the US, residential electric service is almost exclusively single phase. By tapping the secondary on the (single phase) transformer appropriately, you get two hot legs that are 180 degrees out of phase w.r.t. each other, plus a neutral. Hot-to-hot = 240V, hot-to-neutral = 120V.

todd

Look out side & see if 3 transformers are on pole supplying your building,it takes 3

Jr.

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