# MORE Power!!! 120 vs 240 volts



## MRod (Apr 11, 2007)

Hi,

Question to you fine people:

If I change my current 120v 1 1/2 hp Table Saw to 240v (the Rigid tablesaw I have should be able to do both) will I get more power behind the cuts or does it not make a difference?

Thanks,
MRod


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## boboswin (May 23, 2007)

Let me be the first to tell you that the power output will be the same.
Depending on the type of motor you may squeeze out a bit more on the 220 volt hookup.
It will be insignificant though.

Bob


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## RusticElements (Mar 14, 2008)

Depends of the horse power rating of the motor. As a general rule, 240V motors are built to put out more power than 120V motors, but not always. Check the HP rating on both motors. It will either be on a metal plate fastened to the motor (the usual method) or stamped directly on the motor.


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## che (May 18, 2007)

No, changing a dual voltage motor to 240 won't get you any more power.

There are some finer points to consider but if your a hobbyist woodworker (the saw is off more than it's on) there will be little to nothing to gain by switching. However, If the saw runs for hours on end the higher voltage and lower current will keep the wires cooler and will reduce the voltage drop in the wiring which will get you a little more power at the motor.


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## Catspaw (Dec 15, 2007)

I think the benefit to going 240V is it is more efficient. You may not get more HP but you will use less electricity for the horsepower is has.


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## boboswin (May 23, 2007)

Catspaw, I respectfully disagree with you. 
As far as I know the charge for electricity is for Watts and that's* volts times amps*.
It should be nearly the same regardless of the input voltage choice.

Regards
Bob


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## Al_Killian (Feb 15, 2008)

The only difference is if the motor is over 2 H.P. , then it will start much easeir and have alot less strain the motor. Smaller ones will not notice much difference.


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## marcb (May 5, 2008)

Bob,

Its more efficient in terms of voltage drop (you cut that in half), which can be significant in some places making 240 a much better alternative.


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## boboswin (May 23, 2007)

Marchb:
Explain that to me. 
I really don't understand?
Could you show me with arithmetic?

Bob


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## marcb (May 5, 2008)

I'm afraid that I can't remember the exact calculations to use. However I found this calculator on the internet.

http://www.rhtubs.com/voltage-drop_conduit-fill.htm

Running 120V over 100 feet of 14AWG at 15Amp gives you a voltage drop of 9.1 Volts, where as running 240 over the same wire gives you a drop of 4.6volts. If you have thin wires or long runs your motor can act a little wonky, so its better to run 240 in those cases.


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## bayspt (Apr 4, 2008)

Che has it right. Higher voltage means lower current but it shouldn't really make any differance at all. And technically if your wire is the correct size that shouldn't make any differance either.


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## wmodavis (Aug 28, 2007)

It will be some benefit though how much depends on the resistance in the wiring circuit. It will make the most difference if your wiring is undersized because since the 220 v motor draws half the current there will be only *1/4 the power loss* in the wiring. Power loss in the wire is I^2 x R so if the current is halved the power loss is reduced by a factor of 4.

Let's say the total resistance feeding power to the motor is 2 Ohms and the motor draws 10 Amps at 120 V and 5 Amps at 240 V. At 120 volts the power loss is I^2 x R or 10^2×2=200 watts lost in the wiring. At 240 volts 5 ^2×2 = 50 watts lost in the wiring. That is 1/4 the power loss. Now my numbers are made up and the resistance is way higher than you should experience in real life. It does illustrate however that there may be an advantage in using 240 volt wiring. Marchb said you cut it in half but in fact you cut in by 1/4th. Because you cut the power loss in the wiring that much it may actually therefore provide more power to the motor especially at motor starting where the starting current of a motor might be 10 times the running current. The I ^ 2 factor is significantly more important at the higher current draw at statrup.


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## wmodavis (Aug 28, 2007)

P.S. this question is like Adrondack chairs - It just keeps reappearing.


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## Catspaw (Dec 15, 2007)

Bob #2…see Bill Davis above.

240 motors start alittle quicker 'cause they're hit with 240 at start up. A motor will draw alot of current until it gets up to speed and starts generating counter emf. The quicker the start, the less current used for start-up. Also less voltage drop because the amperage is halved so less watts lost in the wiring. Although as Bill pointed out if the wiring is sized correctly, this drop is usually minimal.

These factors are what I consider "more efficient". chances are you'd never notice a difference in your electric bill though.

I've heard that 240 saves on your motor life through less heat. But, I think that isn't true because watts are watts. With 120, coils are wired in parallel, with 240 they're in series. 120V/10A = 5A through each coil or 240V/5A, still through each coil.

What happens if you wire an adirondack chair for 240V?


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## marcb (May 5, 2008)

Catspaw,

Its the voltage drop voltage that causes heat not whats running across it. Its been a long time since I read about electronics, but the voltage drop is how you size what wattage resitor to use.


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## Catspaw (Dec 15, 2007)

Marcb, it's a combination of all things, V,I, and R and depends on what's happening at any given time. Not quite sure what your resistor reference is though.

*I* would find this whole discussion quite fascinating (I have a degree in electronics), but, I'm guessing most woodworkers probably just want to know if it'll sav'em money or giv'em mo' power…..ooo OOO ooo oooo…(primal monkey noises.) We won't have electricity soon anyway and we'll all be using hand saws.


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## marcb (May 5, 2008)

*I'm guessing most woodworkers probably just want to know if it'll sav'em money or giv'em mo' power…..ooo OOO ooo oooo…(primal monkey noises.) We won't have electricity soon anyway and we'll all be using hand saws.*

So then the answer is, only if you have thin wires.

Thank god I'm practicing my handsaw skills. Keep me ahead of the curve!


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## boboswin (May 23, 2007)

???


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## wmodavis (Aug 28, 2007)

"What happens if you wire an adirondack chair for 240V?" An electric chair!
Catspaw is right on of course, its all three cuz they're tied inseparably together.

marcb - "Its the voltage drop voltage that causes heat " That's simply not true. Though as I stated above they are inseparably related. Heat is caused by current (amps) flowing through a resistance (Ohms). Now I'll grant you that the current flowing through a resistance has to be caused by a voltage across that resistance. Again they are tied together by a cause and effect relationship.

You can liken voltage and current to water flowing through a pipe. That is something a bit easier to visualize cuz it's observable with your eyes (presuming you can see through the pipe wall. I can can't you?). The Water pressure is analogous to voltage and the amount of water flowing is analogous to current (amps). The water pressure forces the water to flow through the pipe. More pressure - more water flowing. Voltage similarly forces the electrons to flow through the wire or resistance or motor. If all else is the same in a circuit i.e. resistance, higher voltage means more current (amps) will flow. The heat build up is caused by those electrons forcing their way through the resistance rubbing against them causing friction. You can have voltage but if no current flows there is no heat generated.


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## marcb (May 5, 2008)

Completely misremembered then, I'll have to reread up on that again. I coud have sworn that you plunked in voltage drop when figuring out the power dissipation.


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## wmodavis (Aug 28, 2007)

You can figure power dissipation using the voltage drop since they are all interrelated. If you know the voltage drop across a resistor or other device like a motor then the power dissipation can be calculated as voltage times current or if you dont know the current but do know the resistance you can square the voltage and divide by the resistance. More than one way to skin a cat.


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## wmodavis (Aug 28, 2007)

Bob #2 "As far as I know the charge for electricity is for Watts and that's volts times amps"

Actually the power company charges for energy not power. Energy is watts multiplied by TIME, in other words WATT-HOURS.


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## runngt (Feb 29, 2008)

After looking at my last reliant elec. bill I do believe they have changed the formula to "energy multiplied by hundred dollar bills" and the new factor seem to be x5.

it's not so much the watt hours any more as it is the "fuel surcharge", that durned thing is four times my elec. bill. It's just another person with their hand in my wallet I guess.

runngt


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## boboswin (May 23, 2007)

"Bob #2 "As far as I know the charge for electricity is for Watts and that's volts times amps"

Actually the power company charges for energy not power. Energy is watts multiplied by TIME, in other words WATT-HOURS."

You are probably right, I just don't care.

I attempted to *answer the question *now the thread has turned into some game of semantics.

Nonsense.

Bob


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## CharlieM1958 (Nov 7, 2006)

On any woodworking forum I've ever seen, absolutely *nothing* can start a disagreement quicker than an electrical question.


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## kjwoodworking (Oct 4, 2007)

Wow!
I just wanted to try to explain it another way,I hope that helps.
Will you get more power changing saw from 110 to 220? - no

The main benefit in start up. When you flip that switch and that motor starts to turn there is a lot of power needed to start that motor spinning.

I'm sure you heard about capacitors. Well that is similar to a battery pack that will kick in on start up to help get the motor running.

On 120v you are pulling all the power it takes to start and run that motor from one wire and one breaker. say motor pulls 10 amp on 110v through one wire. (I'm not counting neutral and ground)

On 240v you will be pulling power through two wires and what is essentially two breakers. Now motor pulls 5 amps through two wires. (I'm not counting ground)

On your single phase home or shop panel you have four wires feeding it. 
Two hot wires- each one is a seperate 120v hot leg
one ground
one neutral

A 120 volt breaker uses one 110v leg 
A 240 volt breaker uses two separate 120 volt legs to get a combined 240volts(the two hot legs in the panel)

As stated before using 240v gives the motor two power feeds, which divides the amount of power used on start up and running to two 120v feeds which helps reduce the strain from using just one 120 volt line to feed your motor.

This is most beneficial if you have a lot of equipment to run and may have more than one piece of equipment starting at one time.

The real benefit comes into play with 3 phase power. You save on start up voltage needed, wire size and breaker size which saves money. Big money for someone with a lot of equipment. That's why factories and such will use 480/277volt 3 phase.

Voltage drop comes into play with long runs between the panel and the motor it is supplying.

A good example is a cheap 100 foot 16 or 14 gauge drop cord. If you plug in something that needs very much power say a big 1/2 inch drill and use it much you can burn the motor up. I only use a 12 gauge drop cords.

You loose voltage over long runs of wire. To make up for this, you have to use bigger wire. Say you use 12 gauge on a 20 amp breaker to run a 15 amp motor. (I think 14 is good for 15 amps but with start up you need the 12 and 20 amp breaker) If you are going to have to run that motor at a long distance , say 175 foot then you may need to bump up to a 10 gauge wire which is larger and good for carrying more amps than the 12 gauge. This is theoretical and there are formulas for figuring out the wire size needed for voltage drop out.

If you actually read all this, thanks and I hope it helps explain a little.


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## marcb (May 5, 2008)

Excellent in depth explanation. I would only add that 3 Phase also reduces vibration due to the meshing of power waveforms vs 1 waveform crossing 0 a bunch of times. Theres a huge difference between a Unisaw with a 3 horse motor on 240 and a Unisaw with a 3 horse motor on 3 phase.

But thats fairly out there for home shops, only some of the metalworking kooks I've met managed to get 3 phase to their home shop.


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## juniorjock (Feb 3, 2008)

I've been following this thread and it's very interesting…. but I'll leave all the electrical stuff to you guys. There are three things I don't attempt….... Electrical, plumbing and vehicle exhaust work…..... But I do think I've learned a few things here.
JJ


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## Catspaw (Dec 15, 2007)

Bob #2…. it isn't necessarily nonsense. I've done alot of electrical wiring and I still come up with questions. Those little nuances can really bite you if you're not careful. As the world goes south and people like to do more on thier own, this kind of subject becomes more important. Granted most electrical would be handled by a licensed electrician, but, I think it's important for those who are building thier own shops to understand more about these things.

I don't let ANYBODY do anything for me unless I understand what they're doing and why. I think people would be better off if they didn't disregard things as being "not in their field" and went about their business. This is part of my life education.

I would contend that maybe a forum for technical questions such as this be implemented so people could be more self-reliant and not muddle the simpler questions with the longer more technical explainations. Sometimes I really don't want to get real involved, but, generally I like my home well furnished.


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## BroDave (Dec 16, 2007)

Anything operating on 220 volts always uses less electricity than anything operating on 120 volts, usually half as much. Anything operating on 3 phase power always uses less electricity than anything operating on 1 phase power. For equipment used occasionally you will not see much savings in your power bill. The saving in that case comes from the initial cost for wiring and breaker cost.

Another benefit to 240 volt and or 3 phase is the cost of wire. Less amps means smaller wire size which means lower costs to wire and operate.
Anyone who needs numbers to believe can always check the net or call their power company.


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## wmodavis (Aug 28, 2007)

Electrical stuff is mysterious and many don't understand electrical things and that's OK. If we had to completely understand something before we could use it we'ed be in deep trouble mostly because there would be nothing to do. Take your TV or car or calculator etc etc. That's where specialists or people who know more than we know come in to play and that's what forums are all about. Unfortunately mystery causes misunderstanding and misinformation which if taken for truth can cause someone to do the wrong thing maybe leading to some unfortunate experience.

Speaking of misinformation take the statements made by *kjwoodworking*. Now don't get me wrong - a lot of what he says is very good and very true. Then there is this part

"On 120v you are pulling all the power it takes to start and run that motor from one wire and one breaker. say motor pulls 10 amp on 110v through one wire. (I'm not counting neutral and ground)

On 240v you will be pulling power through two wires and what is essentially two breakers. Now motor pulls 5 amps through two wires. (I'm not counting ground)
.
.

As stated before using 240v gives the motor two power feeds, which divides the amount of power used on start up and running to two 120v feeds which helps reduce the strain from using just one 120 volt line to feed your motor."

I would suggest an experiment to see if it's true. Here it is: Just try to hook up your 120V motor with a single wire from the breaker and see if it runs. Of course it will not run when hooked up with only one wire since there is not a complete circuit. Current has to have one wire for the electricity to flow into a device, such as a motor, and simultaneously a second wire to carry that same current back to the power source. Whether it is a 120 V or 240 V wired motor it takes 2 wires and they both carry the same current - example: both carry 10A if 120V or both carry 5A if 240 V. Get out your ammeter and check it.

Well again I say it's a good thing we don't have to understand it thoroughly to be able to use it correctly. I'm in this forum to learn from guys about woodworking and I do learn a lot. My nearly 50 year career as an electrical engineer didn't allow me nearly enough time in the shop. I'm trying to fix that defficiency now.


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## kjwoodworking (Oct 4, 2007)

"""""On 120v you are *pulling* all the power it takes to start and run that motor from one wire and one breaker. say motor pulls 10 amp on 110v through one wire. (*I'm not counting neutral and ground*)

On 240v you will be *pulling* power through two wires and what is essentially two breakers. Now motor pulls 5 amps through two wires. (*I'm not counting ground*)
.
.

As stated before using 240v gives the motor two power feeds, which divides the amount of power used on start up and running to two 120v feeds which helps reduce the strain from using just one 120 volt line to feed your motor.""""""

Thank you! Bill Davis for clarifying my post.

I apologize to all for any misleading information I have posted.

I merely wanted to explain to MRod and any others who might benefit from the info.

Again sorry to all those I misled into thinking it takes one wire to run your saw.

I wanted to let ones understand too about voltage drop and not running anything on the small gauge drop cords that might hurt their machinery.

Please clarify any discrepancies in my post about that too Bill Davis. I want everyone to have accurate information.

I am not wanting to start a heated debate with anyone here or step on anyone's toes.

Some of the above was sounding way too complicated((I^2 x R or 10^2×2=200 )) and I was trying to break it down for others to understand a little better.

I really like this forum and there are a lot of great people here. It's all about sharing, learning and having a good time.

Thanks for reading and again I apologize for any inconvenience or undue stress my post may have caused fellow lumberjock readers.


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## boboswin (May 23, 2007)

*Just shoot me!*
All the guy asked was… Oh hell, go look it up yourselves.

Perhaps everything you have to say right now is true and scientifically correct but the poor guy just wanted to know what happens if he changes his motor from 110 volt to 240 volts. ( input)
*No more, no less!*

This is a wood working forum and most of us are not here to debate the idiosyncrasies of our chosen professions with the uninformed.

*Take me on in my profession and I garantee I will beat you. 
But that's not what this forum is for!*

My suggestion is:

If you wish to have a debate about current , line voltages, motor configurations, and and phase changes as they affect real systems that this is probably not the place to do it.

If you are most comfortable here then start a thread of your own and debate the respondents.

What will happen is that real woodworkers that care about shop results will probably not respond if they are to be scrutinized and or corrected *in minutia* for the answers given.

I have always tried to respond to people asking for help here and maybe I 'm just making a huge mistake.

Bob


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## juniorjock (Feb 3, 2008)

Has anyone noticed a little something strange about this thread…...? MRod has only posted 19 times in 400 days. The LJ posted a simple question (simple if you know about this stuff) and it has gone way off base. Look through the thread. MRod has not posted any replies, only the original question. I don't blame you MRod.


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## CharlieM1958 (Nov 7, 2006)

That means either we scared him off, or he just stopped by to light the fuse and run for cover. LOL!


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## juniorjock (Feb 3, 2008)

Please say your kidding Charlie?


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## Sawdust2 (Mar 18, 2007)

IMHO the issue is not what happens to one machine on one 120 or one 240 20 amp line.

If you want to run two 15 amp motors on one 20 amp 120 volt line it will be a struggle, if not impossible. BUT if you want to run two 15 amp (when configured as110 volt motors) on one 20 amp 240 volt line it is a piece of cake. In the first case you have 30 amps on a 20 amp circuit, in the second you have just 15 amps on one line.

I'm no electricity whiz. I just know the nuts and bolts, so to speak.

Lee


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## LoneRider (May 6, 2008)

Like a fool I will jump in, I know I will offend some, sorry. I don't know if I am an "electrical whiz", but I am the son of an electrician, EE, and currently am working on automotive power accessory power systems at work.

Power is power, simple and true, running a motor on 220V will be more efficient, heat dissipation in the wires is cut by 1/2 give or take, but that is only waste, the "work" being done, or power used to turn the motor is the same. So you are by no means using 1/2 the electricity, less yes, but not 1/2, just about 1/2 the current.

As well, regardless of if you are using 120V or 220/240V, (I've never lived in a house/apartment that was fed with two legs of a 3 phase, always a single phase transformed with 180deg taps, but that is another discussion  ) there is power going through both wires, has to, current going into the motor on one wire by definition has to go out the other.

Which is the main advantage of running everything you can on 220/240V in your home shop.

So you have three wires (excluding ground) coming into your house/shop, the middle on is the common, and then you have two power lines, in 240V they are 180 deg out of phase, and 220V 120 deg out of phase. Ether power line to ground has 120V potential.

Follow me so far?

So when you run a 120V 1200 watt load on one of your power lines, you have 10 amps coming into your house on the that one power line, and 10 amps going out on your common line.

Okay, now, turn on another 120V 1200 watt load on the same power line, you now have 10 more amps on each line, or a total of 20 amps coming in on that first power line, and 20 amps leaving on the common.

Now switch that second 1200watt load to the other power line, so you have 10amps coming in on each power line, because the loads are identical and 180 out of phase, they offset each other and result in no current going through the common line, which is a good thing™.

recap, so everything on a single power line (phase), you have the full load coming in one one of the phase and leaving on the common, but if you have the load split over both phases, you have 1/2 the power coming in on one phase, the other half of the power coming in on the other, and nothing on the common, life is good.

So if you have your table saw, dust collection, air conditioning, band saw and such all 240V, then technically you can run all of the tools without a common wire. Now of course, you can then go to the next level, and split your shop lights evenly between the two phases. The later has the advantage if you blow a single big fuse, only half your lights go out 

So being balanced is good and fine, but there is a really good practical point, so say, with the AC, dust collection, unisaw going through 6/4" oak, there is a lot of power draw. If all three of them where running on 120V and I accidentally plugged them into the same phase, all that current going through the common wire would cause a voltage drop on the common, equal to that on the power line BTW. That voltage drop would make the common line electrically closer to the power line with the tools on it, thus by definition further away from the other power line, 180 deg out of phase with the first. Realistically, it should not be that much, but at extremes I have heard of house with weak ground/common wires causing bulbs to burn out. Or of course, with all of the loads on the one phase you could accidentally trip the breaker for the house/shop bases on one of the phases. But if all of the big loads where 240V, split on both phases you will never have to worry about load balancing.

Well, sorry for all of those who actually read through my post, yeah, I am a newbie on this forum, work got me behind in some of my web browsing and have some more catching up to do.

cheers,
Tom


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## wmodavis (Aug 28, 2007)

*Mrod* please let us know if we literally buried you with this highly technical stuff that was way beyond what you wanted to know! We're awaiting your " Allright [email protected] Enough is enough! You may be back in your shop cutting wood using 240 or still 120. So be it. But we're sure having fun making your simple question into a major mountain. But like LoneRider said "life is good". And discussion is good too. And making sawdust is good too especially with less voltage drop.


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## freedhardwoods (May 11, 2008)

After reading through all of these posts, not one has stated or hinted at the idea that 120 is better, more powerful, (you pick the term) than 240. All have stated that 240 is either equal to or better than 110 for some reason or another, so if I had asked the question, I would figure that 240 wouldn't hurt anything and it might help, so I would just rewire it and forget it. I have my own ideas also, but that poor horse was dead a long time ago.


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## LoneRider (May 6, 2008)

Bill, David,

Thanks for the morning laugh

Yeah, I kinda did forgot the recommendation, but yeah, I agree, if convenient I would switch to 240V. In fact when I put a window air conditioner in my shop I went a size up to get a 240V unit and I did split the lights between the two phases.

Now sadly, the only dust I will be making this weekend is fiber cement, inside door trim and MDF. But, it is still dust, so life ain't that bad


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## MRod (Apr 11, 2007)

I LOVE IT!

You guys are sooooo passionate and I appreciate when a post goes to a higher level as this post has, not another direction.

I've wired my shop for 15amp and 20amp with 12 and 14guage wire and I have a crazy 210v (I think) for my heater that I wired to. So I am understanding about 60% of your responses.

Let me tell you what I've gotten out of your very thoughtful responses.

"Will you get more power changing saw from 110 to 220? - no

The main benefit in start up. When you flip that switch and that motor starts to turn there is a lot of power needed to start that motor spinning." - kjwoodworking - THANKS KJ

Lonerider, I really like your comments on scaling up to 240v in providing ample power for multiple tools to run simultaneously. Good job commenting.

Bill Davis, I enjoyed your comment "What happens if you wire an adirondack chair for 240V?" An electric chair!
"

I'M GOOD - THANKS FOLKS!


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## runngt (Feb 29, 2008)

MRod,

I am glad you got something out of that…..all I got was a head ache! : ) I am glad you guys know this stuff, I just plug it in and pay my elect bill.

runngt


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## juniorjock (Feb 3, 2008)

My thoughts exactly runngt. I'm lucky enough to have a brother-in-law and a few friends that I can call on for electrical work. Now, if I could get someone to do the plumbing I need done, I'd be set.
JJ


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## tiogaglide (Jul 3, 2008)

One more time, I have 3 1/2 HP air compressor I was trying to run it at my barn which has no ac.I had a 250 ft 10-3 line I ran down.When I pluge it in , it barely turned over.It was a 120/240 volt motor.I rewired it to 240 and pluged the other end to 240.It ran with no problems. Higher volt less current.Just why they run big power lines at millions of volts. Now my question since then I returned it back to 120. My brother is having trouble running small 10 gal sand blaster.Not enough air to keep it going.If I wire it again to 240 will it help?


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## northwoodsman (Feb 22, 2008)

MRod,

If you want more "power" behind your cuts:
1. Make sure you have a sharp, flat, high quality blade.
2. Make sure your blade is parallel to your fence so the material doesn't bind.
3. Make sure your table is rust free and smooth (wax helps).
4. Take your time when feeding material.
5. Most importantly, just enjoy yourself.


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## Sac (Jun 14, 2008)

Great question! One I have asked myself several times and never thought about posting it. All these responses make me feel better knowing I didn't go wrong with the 110v tools.


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## MRod (Apr 11, 2007)

Just upgraded to a WHOPPING 5 HP Powermatic tablesaw.

WOW!
220v running on 10guage on a 14 amp circuit!

I can now experience that the motor makes the difference.
-----
Good thou pointsnorthwoodsman!


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## JohnGray (Oct 6, 2007)

Watts are what you pay for. - Arthur Bolton Physics Teacher 1962


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## goggy (Jan 17, 2009)

I found this site while considering the same topic and joined. Seems like a great forum. I too am considering changing my delta contractors saw to 240v. On my motor label it states 110v/1.5hp 220v/2hp. The issue of hp was never addressed. Is this difference significant or misleading?


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## Woodchuck1957 (Feb 4, 2008)

Goggy, what is the amp draw at 110V ? and at 220V ?


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## tooldad (Mar 24, 2008)

Googy, there may be a possibility that it is a generic sticker put on all motors. I have never heard of wiring a motor to 220 increases HP. If your saw came as a 110, then more than likely it is a 110/1.5hp. Consult a manual or a website with the model number to see if it is changeable. More than likely it isn't. Also if you think, most contractor saws are designed for the contractor that goes from job to job. Most jobs will only have 110.


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## Woodchuck1957 (Feb 4, 2008)

Thats not really true Tooldad, I've heard that *some* of the older Delta Contractor saws the HP did increase. By looking at the amp draw on both voltages would be a good indication if it's true. To my knowledge all the Delta 10 inch Contractor saws with 1 1/2 hp motors are dual voltage, mine is and it was made in 1995. Jobsites usually do have access to 220 V at the breaker box, a 220 V extension cord is usually run and the voltage gets split into two 110 V circuits in a 4 plug outlet box at the end of the cord.


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## doyoulikegumwood (Jun 21, 2007)

ok heres my 2 cents on this and this is what i remember from my years installing hot tubs almost all i repeat almost all motors are designed for 220v unless thier under 1 hp. your saw has 2 ratings becuse it is a 2 hp motor but when it is slaved down to 110v it loses effectcy so delta then rates it for only 1.5 hp tooldad just so you know any U/L rated eleictric any thing can not i repeat can not have a generic sticker. thats a law suit waiting to happin if you are not sure how to convert your motor bring it to a shop that works on moters and have them convert it.


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## Woodchuck1957 (Feb 4, 2008)

Yeah, I have a older Rockwell 9" Contractors saw that was built in 1984 and it has a 110 V, 1 hp motor. 220 V is not an option for that motor.


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## goggy (Jan 17, 2009)

There is a different amperage listed under the 220v column. I will check and reply. Also, the conversion is something I can handle: Is it worth it?


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## Woodchuck1957 (Feb 4, 2008)

I feel that it's worth it on my saw, and I don't get the increase in hp that you do. The reason I feel that it's worth it is alot of people just plug there saw into any 110 V circuit they have in their shop, and I was guilty of doing the same for a few years. The problem with doing that is more than likely other things are running off that same circuit, other outlets, lights, fan, etc. so your starveing the motor for electricity when that happens, especially during startup or under a load. One good indicator is if you turn the saw on and the lights in the shop dim. There are two ways to solve that problem, one is run a dedicated 110 V, 20 amp circuit, meaning one breaker feeding only one oultet, nothing else. Or run a dedicated 220 V, 20 amp circuit. The cost difference between the two is pretty minimal and with 220 V I think the motor runs just a little more efficiently. For my saw I run it on a 220 V, 15 amp dedicated circuit because I don't get the boost in hp, I'm guessing yours will need the 220 V, 20 amp because of the 1/2 hp increase. On my motor lets say that it reads 15 amps /110 V and 7.5 amps /220. on most motors the amp draw at 220 V is half of what 110 V is. If your motors amp draw at 220 V is more than half of what it draws at 110 V your motor may very well increase in hp.


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## sIKE (Feb 14, 2008)

I am not sure of much but I can tell you the blade started spinning up much faster on mu machine at 240v…take it for what its worth…


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## marcb (May 5, 2008)

Lots of shops really have underrated wire for a long run and high amperage and the voltage drop due to that causes the saw to operate less efficiently.

Converting to 220 allows less amperage to be drawn and there for less voltage drop due to wire resistance. Then typically gives you better HP at the motor even if the motor isn't rated for a higher HP at 220.

Again this is only if you have insufficient wiring to power your saw. A 12gauge dedicated circuit should be fine at 110.


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## Woodchuck1957 (Feb 4, 2008)

Thats true Marc, but it should also be noted that realistically the amperage is really the same at 110 V or at 220 V. At 220 V the amps are split in two with two hot leeds, instead of one hot leed that 110 V has. So in a nut shell, they both use about the same amount of total amps.


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## ajosephg (Aug 25, 2008)

Woodchuck - On 110 the current flows through the hot lead AND the neutral/ground. On 220 the current flows in two hot leads and NO current flows in the neutral/ground so therefore the current is half of that used for the same power at 110 volts.


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## Woodchuck1957 (Feb 4, 2008)

LOL, on 110 V if you have power flowing through the neutral and or ground, you got something terribly wrong going on there buddy. I'm sorry, but I'd have to disagree with your theory. For instance at 110 V there is one 15 amp connection or draw, at 220 V there are two 7.5 amp connections or draw.


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## ajosephg (Aug 25, 2008)

Read it again. I said no current (power) flows in neutral/ground on 220. On 110 current flows through the hot (black) wire AND the neutral (white) wire. The ground wire (green or bare) has no current in either case, but - in the case of a 110 volt connection the ground is at the same (0 v) potential as the neutral.


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## Woodchuck1957 (Feb 4, 2008)

Well, to test out your theory that power flows through the white and black wire on 110 V I just went and put a test light in a 110 V recepitacle, one side lights up, the other doesn't. So that tells me only one wire ( black ) is the source of power, which I figured anyway because only one wire ( black ) is connected to a breaker, the white wire goes to the neutral bar inside the breaker box. The same amount of power is used weather your useing 110 V or 220 V.


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## ajosephg (Aug 25, 2008)

> ?


 Plug something into the 110 recepticle and measure the current (with an amprobe or equiv.). You will find the same current in the hot (black) and the neutral (white) wires, and no current flowing in the ground (green or bare) wires.

What you did with the test light is prove that voltage is present, not that current is or is not flowing.

Think about it - current only flows if it has a complete circuit. It can't just flow in the hot (black) wire and no where else!


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## Woodchuck1957 (Feb 4, 2008)

Joe, I think I know what your saying, but then how is a 220 V circuit complete if there is no neutral or loop ? I'm talking power source comeing in, and your talking loops. The tester I used is shaped like a V, has two wires with ends, and a small light. Ground one wire to the wall plate scew and insert the other wire into a slot in the recepticle. Personally I think your a bit loopy, lol, just kiddin, I couldn't resist, it was just too damn easy.


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## ajosephg (Aug 25, 2008)

Hopefully I can explain it with words instead of a picture. Visualize this: The power to your house comes from a transformer with primary and secondary windings. The primary has high voltage (1000 volts or whatever) across it, and the secondary has three wires. (The primary and secondaries are magnetically coupled with an iron core, but are not electrically connected.) The outside wires have 220 volts between them. The third wire connects to the center of the secondary winding. There is 110 volts between each of the outside wires to the third wire. The third wire is known as neutral/common. In your breaker box, the third wire is always connected to the white wires going to the outlets, etc. If you look inside the box, you'll find that this is where the ground wires (bare or green) are also connected. This third wire (neutral) is never protected with a circuit breaker. One of the outside wires goes to the left side of our box, and the other to the right side. For a 110 volt circuit one side goes to a circuit breaker, to a black wire, to the load. A 110 volt circuit breaker only has one terminal. The other side of the load is connected to the neutral bar in the box via a white wire. So the current flows "out" the black wire and "back" through the white wire. It is flowing out of one leg of the transformer, through the load and back through the center tap. Current is only flowing through one half of the transformer. With me so far?

Now for a 220 load - There are 2 circuit breakers built into one housing that connects to the left and right sides of the breaker box. The circuit breaker/s has 2 output terminals, and one of the terminals is connected to a black wire, and the other terminal is connected to a white (usually) or red wire. These wires go to the load, etc. So the current flows "out" the black and "back" throught the white. But, it is flowing out of one leg of the transformer, through the load, and back through the other leg of the transformer. No current is flowing through the center tap, but it is flowing through both halves of the transformer winding. In fact,the center tap is only connected via. the ground wire. You could disconnect the ground wire and the load would still work. Got it??

The ground wires are for safety only so the if a "hot" part of the circuit goes bad it will trip the circuit breaker and keep you from getting zapped.


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## North40 (Oct 17, 2007)

DC (Direct Current) power has a positive and a negative, but AC (Alternating Current) has hot and neutral.

110 AC has a hot which goes back and forth (alternates) between positive and negative 60 times per second (60Hz). 110 needs a neutral (which basically becomes ground at the breaker box) to complete the circuit. 220 AC has two hots which each alternate out of phase with eachother ("A" is positive while "B" is negative, and then "B" is positive while "A" is negative) 60 times per second. The current flows negative to positive (if I remember my electrical theory correctly), so it's completing the circuit on the two hot legs, and doesn't require the neutral.

Interestingly, 440 Three-Phase AC actually has three hot lines all out of phase with eachother. That's when you get into rotary phase converters or having the power company run really expensive lines to your shop!


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## marcb (May 5, 2008)

Woodchuck, the statement that the amps are the same is categorically false. If you're pulling 15A at 110 you are only pulling about 7.5 give or take one 220. The load is based on the potential between the 2 wires which are both hot. You are not pulling 7.5A on each wire, you are pulling 7.5 total.

There is 220V of potential between the 2 hots and 110 between one of the hots and a neutral if it exists (3 wire 220 exists to give both a ground and a neutral if you have 110 circuits like a magnetic contactor with 110 coil)


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## Woodchuck1957 (Feb 4, 2008)

Joe, I guess I'll have to read it a little more, as in over, and over, and maybe over again. Now I'm feelin a bit loopy. But anyway, you say on 220 V the black goes to one breaker, the white to the other breaker. when I had an electrician wire things up out in the shop and he was working on a 220 circuit, he would wrap the white wire with black tape at the breaker and at the recepticle to indicate they are hot and not a neutral.


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## toddc (Mar 6, 2007)

You guys look like you are having fun but I do not have time to join in, I am helping Rita rearrange the living room furniture to accommodate our new sofa table.


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## Woodchuck1957 (Feb 4, 2008)

Todd, I'd really hate to see you miss out on all the info, give me about 10 hours and I'll be over to help, and you can jump in on this mind boggling discussion. lol, Ah hell nevermind, women boggle my mind too, I've got enough problems with the one I got, either which way I'm lost lol.


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## ajosephg (Aug 25, 2008)

Woodchuck - He did it correctly, which I think code requires. The code is a whole different subject that isn't really applicable to this thread.

If you would look inside your box, you'd find that the wires from your 220 recepticle goes to the 2 terminals on a 220 volt CB.


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## Woodchuck1957 (Feb 4, 2008)

Joe, it's not how to wire up 110 or 220 thats the problem, it's the theory aparently, lol. I guess I should of kept my typeing to myself, but noooooooooo. Oh well, I guess it keeps a guy humble when provein wrong sometimes.


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## doyoulikegumwood (Jun 21, 2007)

im just wondering are we all in agreement that if he converts to 220 that he will be happier for it lol or do i need to bust out ohms law and get all technical about the advantages.lol


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## Woodchuck1957 (Feb 4, 2008)

LMAO, I'm not saying ANYMORE !


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## ajosephg (Aug 25, 2008)

I think the bottom line is, with the motor he's talking about, it's not a big deal assuming his house/shop has 12 gauge wiring. If it is 14 gauge then he should go to 220.

To summarize many posts - higher voltage results in less current, and less power drop across the wiring, leaving more power for the motor. There may be some other theoretical efficiency benefits, but they are not significant IMHO.

Last post for me too. Have a good week end all.


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## doyoulikegumwood (Jun 21, 2007)

who would of thought a bunch of wood butchers such as ourselves could get into such a good debate about the pros and cons of one thing i think we can all agree on more power oh oh oh.


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## motthunter (Dec 31, 2007)

use 220… 221 whatever it takes


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## goggy (Jan 17, 2009)

My label says: 110v/1.5hp/12.8amps 230v/2hp/8.6amps


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## Woodchuck1957 (Feb 4, 2008)

If it was me I'd definately wire it up for 230V, it looks like you'd get a boost in HP. I'd also recommend the Fenner Drives PowerTwist V-belt if you don't have one allready.


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## goggy (Jan 17, 2009)

I'll wire it up tomorrow and let you know how it works! Off to that big box store with all the orange colors.


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## SelmaBear64 (Jun 29, 2020)

I've been considering changing my 8" jointer from 120 volts to 240 volts. I trip my breaker a lot when I have multiple machines running on the same circuit (jointer, dust collector, fan, etc.). I'm new to the forum and wanted to know if it was worthwhile. I read all the posts here and it really helped. Thanks guys.


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## clagwell (Dec 20, 2018)

Your jointer and dust collector should be on separate circuits. 120 or 240 makes no difference, you just need another circuit.


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## shampeon (Jun 3, 2012)

+1 to keeping your DC circuit separate from your other machines. If you use only one machine at a time, keeping the jointer/table saw/band saw/planer on the same circuit might work. But the amp draw of the DC plus the amp draw of another machine is going to trip the breaker.

As has been articulated many times above, the main advantages to using 240v is the lower amp draw + voltage drop and that you can use smaller gauge (ie less expensive) wiring.


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## ibewjon (Oct 2, 2010)

When I need a laugh, there are always multiple threads arguing how tools run cheaper on 240 volts. NO, you pay for kilowatt-hours, plus all the add ons to the bill. And there are hundreds of thousands of apartments running on two phases out of three on a 120/208 volt three phase service. And no, you probably don't want three phase power in your home shop because of the extra charges for such a service. And large power lines don't run at millions of volts. 345,000 is the standard, there are some at 765,000, but not many. These large transmission lines run at high voltages because of the wire size. The same for your shop. 240 means smaller wire. If your electrical system has the proper size wire for the distance it is run, there will not be any voltage drop to worry about. The last place to cut corners to save money is your electrical system. Yes, this seems to have its own life. No matter how many times the question is answered and put to rest, it is soon to be reincarnated…...


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