Any benefit in running my bandsaw on 220 instead of 110?

[Ole Anderson]

Run 10/3 everywhere and you'll future-proof your shop for 99% of what you'll ever need. It'll be just a matter of changing the breaker and outlet if you're converting from 120 V to 240 V or vice versa.

Yes. but wiring 10 gage is a real pain. 12 is bad enough after running 14.

And I should have known better about the start capacitor. At least I do now.

[Phillip Gregory]

Sure, but I think what usually happens is:
1) Someone decides their equipment isn't working to his satisfaction on a shared, undersized, long-run, 120V circuit
2) He decides to correct this by installing a dedicated, short-run, heavy-gauge circuit and use 240.
3) Tool works "way better". Must be because of the 240.

If that same new dedicated, short-run, heavy-gauge circuit were run on 120, you'd likely get just as good of performance, it's just that few people do that, because they've been convinced that "240 is better!"

In retrospect, I wish I hadn't bothered with 240V circuits in my garage - they limit where I can move equipment. There is a certain convenience factor of having 120V standard outlets everywhere, versus a mix of 120 and 240.

There are really only a few reasons to run 240:
1) You have a motor large enough (7.5HP+) that can't be run on 120
2) You are running new circuits, and the incremental cost of heavier-gauge wire (for 120 circuits) is significant enough that you're willing to forgo convenience for that cost savings
3) You have an existing circuit that would be undersized at 120, and you don't want to replace it, so you'll switch the motor to 240

Did you mean to write "1.5HP+" instead of "7.5HP+"? A 7.5 HP motor would draw somewhere in the neighborhood of 70-80 amps on 120 volts, and in general motors above 2 HP are 240 volt only.

[Ole Anderson]

Did you mean to write "1.5HP+" instead of "7.5HP+"? A 7.5 HP motor would draw somewhere in the neighborhood of 70-80 amps on 120 volts, and in general motors above 2 HP are 240 volt only.

And, in general, aren't motors over 7.5 hp typically available as only three phase?

[Phillip Gregory]

And, in general, aren't motors over 7.5 hp typically available as only three phase?

Most motors over 5 hp are 3-phase but I have seen 7.5 and 10 hp single-phase motors with some regularity.

[Bud Millis]

Perhaps electrics should be added to the "No Politics & Religion" clause

Yes, electrician by trade, and no I never give an electric spec or answer. Hire an local electrician to do the work or find a local to ask the question.

You must be union. My cousin is the the same way!

[Dan Friedrichs]

Did you mean to write "1.5HP+" instead of "7.5HP+"? A 7.5 HP motor would draw somewhere in the neighborhood of 70-80 amps on 120 volts, and in general motors above 2 HP are 240 volt only.

No, I mean if you have a large motor (perhaps I should have said ~5HP+), you may not have the option to run it on 120 (it might be 240 only). 2, 3, and 5HP motors are all available in 120/240.

[Jeff Raefield]

Jeff, your succinct explanation got me thinking about single phase motors on a three phase system. As I understand it 120V is available between one hot and the neutral on a three phase system and there is 208V between two hot wires. As I recall a couple of old Baldor motors in my shop can be wired 115/230/208V. Some newer motors are 115/230V only. What is the optimal voltage for single phase motors on a three phase system? For example, aassuming the motor is limited to 115/230V would it be best to connect it at 115 or 230V? Considering the logic you just laid out it seems like 115V is optimal for dual voltage motors (i.e. 1.5HP or below with no 208V option) on a 3PH system. What is the effect on higher HP motors in this scenario? For example, 2+HP motors wired for 230V but only receiving 208V?

Up to and including 10HP, there is a high likelihood that commercial and small industrial facilities will have 208Y120V distribution systems, rather than 120/240V 3 phase 4 wire. It's also likely that the facilities are relatively small, so voltage drop from the service point is not likely to be large. Motor mfrs, knowing this, use a "compromise" design criteria for those smaller frames in that the motors are really 230V +10 but -15%. So they can run at rated load from 195.5-253V, and 208V -5% is 197.6V. This means at 208V they are still in spec, though they will pull more current to develop the rated HP, which means they will run hotter. The motors are made with a little more iron in them to absorb and dissipate that extra heat safely which makes them a litle more expensive, but the motor shops can carry less inventory to service the market. Large volume OEMs will often insist on saving that cash and using voltage specific motors and making the user adjust their feed, but off the shelf replacement motors don't need to do that.. The single phase versions of these really are 115/230V, but it's OK to use them at 208V if that's what you have.

[Wade Lippman]

After reading this (ALL), I have made a decision. Everyone here is an either an engineer or a college physics professor.

A few years ago I was suing someone in small claims court. The judge was having difficulties; my explanation made sense, but I was just some schmo off the street and the defendant was an "expert".
The defendant said something really silly and I interrupted, saying that I had an engineering degree and I knew what he was saying was silly. The judge sat up and said, "so you're an expert?!" He was then comfortable ruling for me. I didn't have an opportunity to explain that while I had a BSE, I wasn't really an engineer.

[Mike Dowell]

That's funny Wade! I just left it at 120 for simplicity. It is however, the only device on the circuit, so it's not sharing an extension cord with 3 other devices any more. Yeah!

[Rich Sabulsky]

I had my bandsaw on a 110v extension cord with the dust collector. Right above the bandsaw was an unused 20a 220v outlet on a circuit by itself. For all the obvious reasons, switching made sense for me.

My experience has been that there is no difference between running the saw on 110 vs. 220. Running the DC and the saw without having to run to the panel has been a treat, though.

[Prashun Patel]

I resemble Dan's comment: the 120v run to my jointer was too long, and overloaded. So when I'd start it up, it'd take a 1/2 sec to kick up to full speed and would sag the lights meanwhile.

When I switched to 220, that problem went away.

It seems like it's easier to run more things farther away with 220. I like that.

[Tom Deutsch]

Sorry to chime in on this at a late date. But I actually read this WHOLE thread! I’m a little scared of what that says about me. LOL. What I find interesting is that I’ve been unable to find a good visualization (video or dumbed –down diagram) of how this all works either here or on the internets.
So stop me if I get this wrong. I’m going to ignore the whole “starting winding” and capacitor factors. [clears throat]
In a dual voltage ac motor, you have two “motor” windings. Let’s compare them to Fred Flinstone’s feet in his stone-age car. When the winding is energized, it sets up a magical magnetic field thingy that makes the rotor want to spin. This is akin to one of Fred’s feet reaching down to the ground below him and pulling the car forward.
So – in a 117 volt setup, both motor windings are attached to the same wire, which is like Fred using both legs at the same time – lifting them both up in the air and stomping down on the ground and pulling them toward him in one motion – 60 times a second. The motor is getting 117 volts through each of its windings simultaneously, spinning the rotor with 60 two-fisted zaps every second.
In a 234 volt setup, the motors are attached to separate 117v wires from separate but equal sides of the fuse box. One motor winding gets zapped with 117v for 1/60^th of a second and then the other motor winding gets zapped with 117v for the next 1/60^th of a second. Sort of like Fred pedaling his feet in an alternating motion – like running.
Right?
So I get peoples’ argument that there is no difference, because the net power applied is no different. But I also understand why people say 234v is smoother, because spinning influence is being constantly applied to the rotor via the 2 motors alternately, instead of half of the time via both motors pulsing in unison.
What I DON’T get, is why we call it 234v, since each side is 117 volts (in my workshop) and the alternating pulses are … well, alternating …. and never added together. (Unless there is some push/pull thing happening that makes the voltage double, since one leg becomes the other’s return every 60^th of a second – which I doubt since that seems like it would have some clear and major mechanical advantage.)

[Jason Roehl]

Sorry to chime in on this at a late date. But I actually read this WHOLE thread! I’m a little scared of what that says about me. LOL. What I find interesting is that I’ve been unable to find a good visualization (video or dumbed –down diagram) of how this all works either here or on the internets.
So stop me if I get this wrong. I’m going to ignore the whole “starting winding” and capacitor factors. [clears throat]
In a dual voltage ac motor, you have two “motor” windings. Let’s compare them to Fred Flinstone’s feet in his stone-age car. When the winding is energized, it sets up a magical magnetic field thingy that makes the rotor want to spin. This is akin to one of Fred’s feet reaching down to the ground below him and pulling the car forward.
So – in a 117 volt setup, both motor windings are attached to the same wire, which is like Fred using both legs at the same time – lifting them both up in the air and stomping down on the ground and pulling them toward him in one motion – 60 times a second. The motor is getting 117 volts through each of its windings simultaneously, spinning the rotor with 60 two-fisted zaps every second.
In a 234 volt setup, the motors are attached to separate 117v wires from separate but equal sides of the fuse box. One motor winding gets zapped with 117v for 1/60^th of a second and then the other motor winding gets zapped with 117v for the next 1/60^th of a second. Sort of like Fred pedaling his feet in an alternating motion – like running.
Right?
So I get peoples’ argument that there is no difference, because the net power applied is no different. But I also understand why people say 234v is smoother, because spinning influence is being constantly applied to the rotor via the 2 motors alternately, instead of half of the time via both motors pulsing in unison.
What I DON’T get, is why we call it 234v, since each side is 117 volts (in my workshop) and the alternating pulses are … well, alternating …. and never added together. (Unless there is some push/pull thing happening that makes the voltage double, since one leg becomes the other’s return every 60^th of a second – which I doubt since that seems like it would have some clear and major mechanical advantage.)

Nope, that's not how dual-voltage motors work. When a dual-voltage motor is connected to 120V, both windings (or groups of windings) are connected to the hot wire on the "front" end of the windings, and the neutral on the "back" end of the windings (a "parallel" wiring scheme). When connected to 240V, one hot leg of the 240V supply is connected to the front end of one winding, then the back end of that winding is connected to the front end of the second winding, then the back end of the second winding is connected to the second hot leg of the power supply (a series winding).

To your voltage question, they ARE additive, so while one hot leg is 120V positive in relation to ground, the other hot leg is -120V in relation to ground, adding to 240V between them (it's a little more complicated than that, as those are RMS--root means squared--voltages, so the peak voltages are actually about +/- 170V).

[Mike Henderson]

In a 234 volt setup, the motors are attached to separate 117v wires from separate but equal sides of the fuse box. One motor winding gets zapped with 117v for 1/60^th of a second and then the other motor winding gets zapped with 117v for the next 1/60^th of a second. Sort of like Fred pedaling his feet in an alternating motion – like running.
Right?

Sorry, not right. What you are doing in your thinking is looking at the voltages in each hot wire to ground (or neutral). But ground (or neutral) is not involved in the circuit. All you have is two wires with 240 volts across them. One sinusoidal voltage between two wires.

Jason has given a good explanation of how the motor is wired for the 120 volts and 240 volts.

Your view is a common misconception about power in a residential application. People seem to think of it as some kind of two "phase" system, with 120 volts for each "phase". That's completely wrong. There are only two wires delivering power to the motor and there is only one phase (or sinusoid) across those two wires.

Mike

[Malcolm McLeod]

There is a relatively convenient way to wire BS motor at 230V/1ph, but keep the attached task light on 115V.

The 'middle' leg of the motor wires, not the two hot 'feed' legs, is basically a neutral (where the 2 sine waves cross). You can get 115V between 1 of the hot legs to this middle leg. On some motors!!

And it beat$ pulling a neutral wire from the panel, just for a bulb. Be aware that it puts a small imbalance on the main 230V feed. So no 800W bulbs or 2hp feeders.

Just make sure to verify all of this with a meter, or call your favorite electrician.