# Why upgrade machine to 220v



## leftcoaster (Jan 1, 2016)

I know that 220 opens up the possibility of larger motors. But suppose I have a machine that comes wired for 110 and for which I have enough amps to not worry about tripping a breaker.

What's the argument for making the 220v upgrade in this case? Do things run cooler with lower amperage?


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## jonah (May 15, 2009)

Assuming that the wire is sized appropriately, there is no good argument for changing to 240V. With the right size wire, heat is not an issue.


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## rad457 (Jun 15, 2013)

I assumed lower operating cost as around here we are charged by the KWh, so fewer amps used? When I switched a few machines to 220v they seem to start/run smoother.


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## TheFridge (May 1, 2014)

Operating costs will be the same.

Lower amperage is a plus.

Technically there isn't a difference on paper. In real life I find there is a small one. How it sounds when starting and in use is one.


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## wapakfred (Jul 29, 2011)

> Operating costs will be the same.
> 
> Lower amperage is a plus.
> 
> ...


That's pretty much my opinion as well. But if you're good with 120V, stay that way.


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## ssnvet (Jan 10, 2012)

W = V x A, so if you double V, you use 1/2 A, but the total power consumed will be essentially the same. Power companies bill by KWHr. (1,000 Watts pulled for 1 hour) so given the same W… Their is no theoretical savings.

But, as you push amps through a wire you create some thermal losses however (calked I squared R losses, where I is the current and R is the resistance in the wire). Copper, being an excellent conductor has a very, very low R value, so the heat generated is small, none the less, a 1 KW motor will have greater thermal losses running at 110 V than at 220 V, and thus will consume a little more power, and cost a few pennies more to run. In practicality, this is a very small factor.

But power is not the only consideration as torque also comes into play, and the motor will have more torque when powered by 220 V. This is primarily noticed when the motor starts and the 220 V motor will start more smoothly with less of a jolt and a lower current spike (so no dimming of the lights or tripping of breakers).

As noted by the OP, 220 V gets you into larger motors. Some don't think this is a big deal as they run their "2 HP" DCs or "5 HP" shop vacs on 110 V, so who needs 220 V. But physics doesn't lie… product marketers, on the other hand, do, and they create confusing terms such s "developed HP" or "peak HP" to muddy the waters.

In reality (just do the math) the maximum power you can get out of a 110 V, 15 amp circuit with an 80% efficient motor is 1 3/4 HP. If you want more than that, you need to go 220 V.


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## ArtMann (Mar 1, 2016)

Well, I am an electrical engineer and have spent a career dealing with these kinds of issues. If the wiring to the motor in question is adequate, then there is absolutely no difference in performance of the motor either way. That is a big "if" though. Furthermore, power is purchased by the watt, not by the amp. The wattage consumed by the motor is the same in either case. As an example, a 1.5 horsepower motor running at 120VAC and 15A can be reconfigured to run at 240VAV and 7.5A but the power is 1800 watts in either case.

There is one issue that makes 240VAC conversion a good idea. If you have an auxiliary breaker box that is fed by a 240VAC cable with a marginal current capacity, it is necessary to maintain a balanced load so that the load on either leg is not exceeded. Reconfiguring 120VAC motors to run on 240VAC will automatically distribute the load at 50/50. That is my situation.


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## ssnvet (Jan 10, 2012)

Three phase is the cat's meow, as the motors do not required starting capacitors and don't have a big current surge upon start up. Copper is expensive and you can power the same motor with fewer amps whe using 240 three phase, so your circuit will not require massive 10 or 8 gage cables and your installation costs are a lot lower.


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## Loren (May 30, 2008)

You can get by in woodworking running 
110v machines only. The work will get done
slower, that's all. Obviously some machine
types are only intended for professional
use so if you get into any kind of real
manufacturing of wood products 220
and even 3-phase power rapidly become
must-haves.


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## AlaskaGuy (Jan 29, 2012)

> Three phase is the cat s meow, as the motors do not required starting capacitors and don t have a big current surge upon start up. Copper is expensive and you can power the same motor with fewer amps whe using 240 three phase, so your circuit will not require massive 10 or 8 gage cables and your installation costs are a lot lower.
> 
> - Mainiac Matt


There is a down side to 3 phase also. Unless you live in a commercial zone most of us can't get 3phase power unless you buy and install a phase converter. That's what I did and by the time I was finished I had almost $2000 in my system.

If and when I go to sell my equipment it's going to be hard to do…... who knows how low I'll have to go to sell them.


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## clin (Sep 3, 2015)

Agree with the not much practical difference. But, the 240 V will have slightly more power becasue of the lower current. As discussed, less current results in less power loss in the wire (insignificant in terms of electric bill, if in fact it has any effect at all).

The higher current of the 120 V will drop 2X voltage in the power wires. This will result in slightly less voltage at the tool. The tool will therefore operate at a lower power.

A 50 ft run from your breaker box to the tool is not unusual and is probably on the short side. This would result in 100 ft, round trip, of wire. Assuming #12 wire, at 1.7 mOhms /ft, 100 ft results in 0.17 ohms of resistance.

Assume a 10 A draw. This results in a voltage drop of 1.7 V or about 1.4% of available voltage. Not huge, but not completely insignificant either. There is a bit of a complex interaction of the motor characteristics (power, torque, voltage, current and power factor). Therefore it isn't simple to say exactly what the result would be. But in general the available torque is related to the square of the voltage.

So a drop of 1.4% of voltage would be in the range of 3-4% of torque compared to having no wire loss.

At 240 V, the nominal current is half (say 5 A), and the voltage is twice as large. So first off the voltage drop is now half or just 0.85 V and this is just 0.35% of the voltage. This results in about a 0.7% drop in torque compared to having no wiring loses.

So going to 240 V might give you about 2-3% more torque.

Of course actual torque draw depends on the cut being made so on ad so forth.

If it were me, I wouldn't change it unless i had a problem I was trying to solve (like a need to reduce current on a shared circuit that trips a breaker). I doubt a few percent more in torque is going to be very noticeable or useful.


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## kelvancra (May 4, 2010)

Except many of us are running everything through 20 amp circuits, so you can bump that a little. No?



> In reality (just do the math) the maximum power you can get out of a 110 V, 15 amp circuit with an 80% efficient motor is 1 3/4 HP. If you want more than that, you need to go 220 V.
> 
> - Mainiac Matt


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## kelvancra (May 4, 2010)

If much of what many say here is true, those who make fun of me for running ten gauge on all my 240 circuits are missing a critical piece of the puzzle.


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## 000 (Dec 9, 2015)

> If and when I go to sell my equipment it s going to be hard to do…... who knows how low I ll have to go to sell them.
> 
> 
> 
> ...


I'll buy your stuff. Lets start with the Feldor…....


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## ArtMann (Mar 1, 2016)

I think it is smart to run all 30A 240V circuits but not for the reason you are giving. I like the flexibility to replace 3 hp machines with 5 hp machines without changing any wiring. The 1 or 2 percent difference you might get using heavier wire would not be detectable without sophisticated electro-mechanical load test equipment. It might be the same difference you would experience between a saw blade that is new and the same blade a week later.


> If much of what many say here is true, those who make fun of me for running ten gauge on all my 240 circuits are missing a critical piece of the puzzle.
> 
> - Kelly


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## kelvancra (May 4, 2010)

Actually, my whole reason for ten gauge is the "penny wise, pound foolish" thing (basically, what you said). Once the rock is on, the only way to get more power to an area of the shop is across the walls, rather than in them, AND it doesn't hurt a thing to have too many clamps. I mean, too much capacity available at a plug. Of course, that doesn't mean I'm going to feed my Unisaw with four ought.

There have been too many times, over the last fifty years, I needed more power, lucked out and got away with running a space heater off the same circuit as the TV and lights on a sixty amp fuse panel and so on..

As a kid, the experts KNEW we didn't need more than sixty amps. Not much has changed. Today, the experts KNOW two hundred is over kill in many shops and homes. Sometimes they forget different parts of the country have different resources and needs. For example, I live just a few miles (literally) from two dams on the Columbia River and what folks on the cost pay three hundred for, I get for seventy.


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## Redoak49 (Dec 15, 2012)

I was really glad when I put in my dust collector that I had specified 10 ga for all my 220 circuits. It was a few bucks more but saved money when I put in a 5 hp dust collector.


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## knotscott (Feb 27, 2009)

It's not uncommon for a 120v circuit to suffer voltage loss. Since 240v splits the current across two hot leads, it's rare for 240v circuit to ever suffer from voltage loss. If you have 220v available, just switch it over. There might not be any notable improvement, but if your 120v was causing any motor lag, you may find that 220v gives faster startups and faster recovery from heavy loads, which can give the impression of improved power from the motor.

If 220v is not currently available, it may not be worth your while if you're getting satisfactory performance from your 120v circuit.


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## leftcoaster (Jan 1, 2016)

This forum is incredible. Thank you all for these informative responses. Happy Independnece Day tomorrow if you're in the States.


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## BillWhite (Jul 23, 2007)

Matt, are ya tellin' me that my 6 1/2 HP Ridgid vacuum can't run on the 110V wall plug? (You DO know that I'm jokin'?)
Where's Tim The Tool Man when ya need him?
Now, after that bit of levity…....
I do run my TS and compressor on 240 'cause I have the shop wired that way. Start up seems to be a bit faster.
Other than that, no diff…............
Bill


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## Sparks500 (Jun 30, 2017)

Running 3 phase equipment doesn't necessarily mean an expensive phase converter. You can simply get a frequency drive and feed it 240 volt single phase. It will have to be at least ⅓ oversized capacity. I got a Chinese made 5hp for around 130 bucks to run an old Powermatic bandsaw I had. It was nice because you can soft start it and use dynamic braking to stop it faster. Plus, you can dial in your speed to suit you projects.


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## johnstoneb (Jun 14, 2012)

knotscott nailed it. When I changed my TS to 220 I noticed it was immediately on speed when turned on and didn't seem to lug down as much. The reason I changed to 240 was a new shop and I rand several 240 lines for various tools. I would still be on 120 if I hadn't done that. If you have 240 available change if not it is not worth running the line to change.


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## MrUnix (May 18, 2012)

> Running 3 phase equipment doesn't necessarily mean an expensive phase converter. You can simply get a frequency drive and feed it 240 volt single phase. *It will have to be at least ⅓ oversized capacity*.
> - Sparks500


That is not really accurate… in fact, you can undersize a VFD in many cases, depending on the application. And for those VFD's that want 3-phase input (5hp and over), you can still run them on single phase, but should oversize by roughly 50% (most manufacturers recommend anywhere between 50-70%).

As to the 120v versus 240v issue on dual voltage motors, the coils inside the motor will only see 120v either way. The internal resistance will change slightly (series versus parallel), but in real life, it makes little difference given the extremely low values present.

Cheers,
Brad


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## Ocelot (Mar 6, 2011)

I wired my dishwasher on 6 AWG. It's not in my shop, but I tested it there, so I suppose I can mention it here. ;-)

As it turned out, I ended up returning the used 50 Amp dishwasher (which failed the tests) and buying a new 40 Amp dishwasher, but I already had the wire so I just got a different breaker and used it.

When I had it set up in the shop, it was coming out the top of the breaker panel and running over the garage door and the lumber rack. My son asked if the water came through that hose. "No, that's a wire."

While shopping that, I noticed that I could buy 250' of 8 AWG pretty reasonably at Home Depot, of all places, and resolved to do that next time I need to wire anything - so I can overdo and have leftovers for all future wiring projects.

My 5 HP planer is on 10 AWG, but once you figure the value of your time (or the electrician's), you might as well oversize it one click.

-Paul


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## Carloz (Oct 12, 2016)

The only reason to go 220V is machines that draw more than 110V can supply, which normally is 2HP.


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## Fresch (Feb 21, 2013)

To the op question no.
If at 120 v 1200watts, 240v 600watt x 2= 1200watts, watts are watts, same heat, same work, basic same cost to control, same elec. cost, equipment was made to run at the 120v or 240v so what is the need? 
Go 3 phase need new more $ service if you can get one, controllers, etc., unless your going pro or get a great deal on equipment then ok.


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