110V or 220V

[George Bregar]

I love how electrical threads always go on and on...the OP's question was answered in full many posts ago...and off it goes on motors, AC "how it works"

[Barry Lyndon]

I love how electrical threads always go on and on...the OP's question was answered in full many posts ago...and off it goes on motors, AC "how it works"

And I'm reading every post. It's an interesting and pertinent thread for me right now so if people want to give their thoughts, I'm interested in reading them.

[Ole Anderson]

Only reason to rewire for 220V is that you might trip the 110V 20A breaker if you stall the saw.

I presume this was said tongue in cheek. Personally, I want the breaker to trip if the motor stalls and significantly exceeds its rated amperage draw while I try to find the off switch while juggling a board that is jammed in the blade.

And having NEC require a 10 ga wire for a 1.75 hp shop motor, I guess I better do some reading, never ran across that.

[George Bregar]

I presume this was said tongue in cheek. Personally, I want the breaker to trip if the motor stalls and significantly exceeds its rated amperage draw while I try to find the off switch while juggling a board that is jammed in the blade.

Uh, wasn't and your scenario isn't really what I was thinking of. Was thinking of more "slowing" the blade. Which isn't that hard to do with a smaller contractor saw.

[Dan Friedrichs]

Uh, wasn't and your scenario isn't really what I was thinking of. Was thinking of more "slowing" the blade. Which isn't that hard to do with a smaller contractor saw.

If it's a smaller saw, then even if you bog it down, you might well not be pulling close to 20A.

[scott spencer]

If 220v is readily available, I'd definitely make the switch. There's next to zero downside, very low cost involved, and some possible noticeable improvement in performance, depending on the motor and circuit involved. I switched two, and noticed faster startups and faster recovery on both...one more so than the other. The "theory" tells us that there is no difference, but the reality is that a 220v tends to have less voltage loss in many situations...it may or may not be noticeable, but it's very easy to do to find out.

[Dave MacArthur]

I like 240 volts because it prevents my friends and neighbors from being able to borrow my tools unless they come to my shop to use them.

THIS is a point I've never seen made, and while it made me laugh, it's a very valid attitude! Good one!

[Darius Ferlas]

I have a TS that draws 13amps. I used t run it on a 15amp circuit until I upgraded the wiring in my garage. The plan was to run the saw on 220. Having checked it out on a 20amp circuit I noticed enough improvement, so I never got around to rewiring the motor to 220.

I heard rumors that running TS on lower amperages extends the life of the motor.

[Mike Cutler]

I'm afraid that's not correct. When you run a 220V circuit, there are only two wires that carry the current and voltage. The neutral (or common) is not part of the circuit. The reason you have half the current in a 220V circuit (for the same load) is that power is voltage times current (when power factor is ignored) so when you double the voltage, you halve the current.

Mike

What a dummy I am! Thanks Mike.
I can't type for beans. The original intent of my post was to identify that Power, in Watts, was less on either of the two hot legs, as the current was being applied in a 2 pole 240 circuit.
To the OP, Watts is Watts. A 1.75 HP motor requires the same amount of Watts to run for a given load applied, whether 240, or 120. The difference as Mike pointed out is that the applied voltage determines the current drawn on any single conductor at any given time.
Thanks again Mike for clarifying that.

[scott spencer]

I have a TS that draws 13amps. ...I heard rumors that running TS on lower amperages extends the life of the motor.

Darious - I'm far from an expert in this field, but if I understand correctly the motor's coils split the load of that 13 amp draw evenly regardless of how the motor is wired. If wired for 110v, the entire 13 amp load is carried by a single 110v supply leg. If wired for 220v, the 13 amp load is shared by two 110v supply legs, each carrying half the load. A supply line tends to be more efficient at supplying peak loads if it's not operating near it's capacity limit, meaning that the 220v typically has better ability to handle peak loads than 110v, but the wire used, and the particulars of any given circuit are a factor too. If wired for 220v, you motor is likely to experience less heat caused by voltage loss during peak demand, which in turn could help extend the life of the motor. I'm sure the experts will correct me if I'm wrong.

[Jim Falsetti]

Mark,

If your new table saw is a Delta Contractor saw, somewhere, perhaps in a FWW tool review, I read that the saw has more power at 240V. Something about a set of windings in the motor that are energized at 240V but not at 120V.

Jim

[Barry Lyndon]

Just a quick question on topic (it should be quick, otherwise I would start my own thread)... First time rewiring for 240 so noob questions follow...

If I were to rewire my bandsaw to use 240 instead of 120, should I get a plug and receptacle to match the amperage of the breaker for the circuit? Or do I get a plug and receptacle to match the max amperage of the machine? I have a 20 amp breaker for the 240 line so would this be what I'm looking for
http://www.amazon.com/Leviton-2320-R...bxgy_hi_text_b
and
http://www.amazon.com/Leviton-2321-L...ef=pd_sim_hi_2

There are also these...
http://www.amazon.com/Leviton-2620-R..._bxgy_hi_img_b
http://www.amazon.com/Leviton-2621-L...5890916&sr=8-1

...if getting a 30 amp setup would be useful for some reason.

Lastly, do the plugs usually come with a cord or do I need to buy that separate? If separate, what do I get?

[Homer Faucett]

If 220v is readily available, I'd definitely make the switch. There's next to zero downside, very low cost involved, and some possible noticeable improvement in performance, depending on the motor and circuit involved. I switched two, and noticed faster startups and faster recovery on both...one more so than the other. The "theory" tells us that there is no difference, but the reality is that a 220v tends to have less voltage loss in many situations...it may or may not be noticeable, but it's very easy to do to find out.

+1. Speak in theory all you want, and hypothesize that the power loss due to resistance is negligible, but my real-world experiences tell me that I'll use 230 on dual voltage machines whenever practicable.

I've personally experienced noticeable differences in startup speed and power on stock length cords when converted from 110 to 230 on both contractor saws and jointers.

[David Castor]

If you have a dedicated 120 V circuit of the proper rating and wire size, there is not going to be much difference. But in most garages and basements, there are not many dedicated 120 V circuits. If you have to run a new circuit anyway, it makes sense to run 240 V. You can use smaller wire, there is less voltage drop and less noticeable flicker on other circuits when starting the saw. There is little to no cost difference in running a 240 V circuit versus a 120 V. If you need a 30 A 120 V circuit, it will be cheaper to run a 240 V circuit, since you will only need a 20 A circuit.

Also, there is no need for twist-lock plugs/receptacles for a 240 V circuit at least in my mind. They look cool, but they are much more expensive than a standard straight blade set.

[Dave MacArthur]

If I were to rewire my bandsaw to use 240 instead of 120, should I get a plug and receptacle to match the amperage of the breaker for the circuit? Or do I get a plug and receptacle to match the max amperage of the machine?

More complicated than you'd expect...
If you're using the "toaster or coffee maker plugged into a 20A kitchen circuit" analogy, then you only need the plug to match the max amperage of the device it feeds.

Folks bite off on this all the time and forget that for motors in a shop, you probably took advantage of some assumptions that disallow this attitude/analogy.

If you're running a 230V circuit in a garage or basement (below grade) shop, and you DIDN'T put a GFCI breaker on it, then you are likely using the exception for "dedicated circuit" in the NEC (even if you didn't know it)... and if you're using a dedicated circuit then you should make everything on that circuit match the possible amperage of the circuit. Again, there are arguments to be made for the view above, but IMO once you're assuming a dedicated 230V circuit, then dedicated means calculated for and engineered for the load on the circuit. Therefore, IMO, the correct answer becomes making the extension cord, plug, receptacle, and wiring all match the proper load calculations for your machine. I would then make the CB match that load, with the caveat that for motor loads I know that motors may be thermally overload protected which allows me to boost the CB amps higher IF NEEDED to allow startup without problems (IAW some complicated rules in the NEC).
Remember, the entire point of all these calculations and circuit breakers is to keep your house from burning down. When wires and their terminal connections (plugs, receptacles, lugs/screws) have electricity flowing through them, they get HOT. The CB is on there to limit the flow of elec. (amps) to an amount that EITHER the wire itself OR the terminal connections can take and stay cool enough to meet NEC requirements. So, if you have a 12 ga wire with a 20A circuit breaker, then you need 20A receptacles and plugs on it. And sure, if you're plugging a thermally overload protected toaster or such into it in a non-dedicated circuit way, obviously you use the plug that matches the toaster.