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220 vs 110 Volts

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Forum topic by Glen Peterson posted 01-24-2010 01:12 AM 10494 views 0 times favorited 18 replies Add to Favorites Watch
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Glen Peterson

556 posts in 2517 days


01-24-2010 01:12 AM

Topic tags/keywords: motor voltage electricity

I just bought a jointer and the motor can be wired for either 220v or 110v. I’m planning to wire it for 220 because I assume that 220v would produce more power from the motor. I’m thinking this way because my more powerful tools (TS, planer, lathe) all run on 220. Is my assumption regarding power correct? Are there other advantages to running on the higher voltage? Finally, is there a formula that describes the relationship between voltage and power in a motor?
Thanks,
Glen

-- Glen


18 replies so far

View seriousturtle's profile

seriousturtle

101 posts in 2791 days


#1 posted 01-24-2010 01:34 AM

I’ve read that running these bigger machines on 110 can strain the motor. If you are able to use 220, do it. I’m in the process of running a sub panel in my detached garage, just to get some 220 out there. Plus, I’m running everything off of one outlet, which sucks.

-- ~the turtle

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Brian024

358 posts in 2860 days


#2 posted 01-24-2010 01:35 AM

It won’t produce more power, but the motor will run more smoothly. It will also draw less current then the 120v. I believe 746 watts equals 1 horsepower, which won’t be exact in a motor because of the in-efficiency; i.e. power factor. Which is why a lot of 120v motors have capacitors, to help them get the needed current on start up or when put under load.

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knotscott

7208 posts in 2836 days


#3 posted 01-24-2010 02:35 AM

It definitely won’t produce more power on 220v, but it might improve the performance of the motor if the 110v circuit isn’t up to par and is starving a motor for juice. If the 110v circuit is supplying all the needed amperage, there will likely be very little difference. It really depends on the particular motor characteristics and the particular supply circuit involved. Because of the huge amp draw at startup, most motors will experience faster startup on 220v because it does it a better job supplying peak amperage. On my former GI 50-185 contractor saw and Craftsman 22124 1-3/4hp hybrid, I found it recovered from bogging down faster on the 220v as well, but your mileage will vary.

Bigger motors run on 220v because they draw more amperage than a standard 110v circuit can supply. Most 110v circuits can only supply the necessary amperage for up to ~ 1.75hp motors, which draw in the range of 14 to 18 amps nominally.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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DaveBaker

65 posts in 3212 days


#4 posted 01-24-2010 02:39 AM

The higher voltage will allow the motor to run more efficiently. If your able, run 220 to it.

-- Upstate New York -- Do what you love and never work a day in your life.

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PurpLev

8523 posts in 3109 days


#5 posted 01-24-2010 02:42 AM

voltage x amp = power (wattage) if your saw draws 20 amps using 110v, it’ll draw 10 amps using 220v, either way it’ll have the same power. so NO, you will not get more power from it. now, if your current wiring in the house can only support 15 amps, then switching to 220v will allow your wiring, and your breaker to take the load better, and not spike. 220v also runs the wires cooler in general, and is more efficient. if you currently have a 30amp circuit running 110, there will be little benefit from switching the saw to 220 which also involves you replacing the saws power cord and outlet.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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SnowyRiver

51452 posts in 2941 days


#6 posted 01-24-2010 03:33 AM

I dont believe it would make a difference in the motor performance. The motor will draw whatever current it needs. Its just that if it draws more than what the 120 V circuit can provide, it will blow the breaker. A 120 VAC circuit generally uses a 15 (lighting) or a 20 amp breaker, and a 14 or 12 gauge wire. A 220 VAC circuit uses a minimum 30 amp breaker and by most codes requires a minimum 10 guage wire since you have the potential to draw more current. A larger gauge wire is needed because of this potential to draw higher current with 220 V. The higher the voltage, the less current required to produce the same power.

Power = Votage X Current. So you can see if one component goes up, the other can ge reduced to produce the same power.

Higher voltage is usually used when there is a need or a potential to draw a large amount of current much like you do with higher powered table saws, planers, etc. Which in turn keeps the wire gauge at a workable size.

I would also suggest that the motor would only run more smoothly if you went to 3 phase power.

-- Wayne - Plymouth MN

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bob101

289 posts in 2911 days


#7 posted 01-24-2010 04:46 AM

I find my 220 running tools start up to full hum quicker and they draw about half the amperage of 110 wiring for the same tool so switch em all over to 220 if you can.

-- rob, ont,canada

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SnowyRiver

51452 posts in 2941 days


#8 posted 01-24-2010 05:39 AM

CessnaPilotBarry,

Yes you are correct. As long as its a double pole breaker you should be able to use smaller ones. I probably didnt make myself very clear. I was trying to reference Glens comments about tools such as higher powered saws, planers etc, that its best to use 220 at 30 amps. That should handle most of what we use.

-- Wayne - Plymouth MN

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TopamaxSurvivor

17654 posts in 3136 days


#9 posted 01-24-2010 05:45 AM

Charlie, Get the popcorn!!!!!! :-)) The bottom line is a watt of power is a watt of power no matter what the voltage is. The perceived differences in performance when reconnecting a 120 volt saw to 240 volts has to do with voltage drop caused by line losses in the wiring at a twice the current flow at the lower voltage. The actual power is the same. This is why they say not to use long extension cords.

The capacitor on 120 volt saws need to be there after they are connected to 240 volts. It tells the motor which way to spin on start up.

Finally, P=IxE or power = amperage x voltage. Real power in alternating current circuits has to take inductance into account, so it isn’t as easy as it looks at first glance. 746 watts are supposed to be 1 horsepower, but I have not seen a motor name plate that works out with the 746 watts in the last 40 years.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View norwood's profile

norwood

303 posts in 2530 days


#10 posted 01-24-2010 08:05 AM

as a fellow electrician you also have to take into account the load being placed onto the motor a 120v motor at 20 amps with no load will run just as efficient as a 220v motor at 10amps “with in reason though the math might say differently”
but when full load “lots of use” the 220 will generally run a bit better but the cables should be run to allow for changes in load/usage so even though a 10amp wire only requires a 14/2 copper conductor I would suggest a 12/3 for saftey and the possibility that you might change machines to something better in the future
just my 2 cents

-- of all the things Ive lost in life i miss my mind the most

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TopamaxSurvivor

17654 posts in 3136 days


#11 posted 01-24-2010 08:56 AM

You guys should just forget 746 watts per horsepower. It really is quite misleading for small single phase motor power circuits. The code wiring requirements for a 1 Hp single phase motor is based on 16 amps at 120 volts or 8 amps at 240 volts. Using the 746 watts/hp figure, that comes out to almost 2.5 hp!! There are so many other factors involved that cause power losses, it is useless in small single phase motor calculations.

When calculating small Direct Current motors, 746 watts/hp is a lot closer. It is closer yet calculating wound rotor induction motors.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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norwood

303 posts in 2530 days


#12 posted 01-24-2010 07:44 PM

I agree with top max on the hp issue even though a motor is rated at 1 hp at 20 amps which would require a 12/2 “to correct my previous error” and a 14/3 at 220v depending on wiring it could only require a 14/2 “its depends on wiring and winding” if the motor wont start or blows the breaker at start up Canadian electrical code “very similar to American, since its based off the same manuals and requirements” will allow a 120v 20 amp motor to be placed onto the next standard size up of breaker 25 or 30 as long as the cables to the motor are sized accordingly.
Though this rule is intended for larger industrial applications it does apply because the HP ratings of motors is based on factory testing on multiple motors and mathematical equations the device you end up with might say 2HP “1492 watts” but it could draw the same load as a 4hp motor at start up though a single phase motor has capacitors to assist in startup and smooth operation. and usually doesn’t have those problems.

This stuff gave me a headeach at school what do you think its doing now

But I would suggest bringing in a larger wire in case you change machines in the future and a three conductor at that even if there is an extra wire in the panel and connection box” though not generally accepted in code requirements” the cost isn’t that much different and the struggle later to replace it is worth the time and cost now
Thanks

-- of all the things Ive lost in life i miss my mind the most

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Glen Peterson

556 posts in 2517 days


#13 posted 01-24-2010 10:21 PM

Thanks for all to great information.

-- Glen

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PBthecat

53 posts in 2511 days


#14 posted 01-25-2010 12:21 AM

One thing to consider is that you use 2 circuit positions on a 220v line. That may have an impact on things depending on how much space is in the panel box

-- "Every hundred years, all new people"

View TopamaxSurvivor's profile

TopamaxSurvivor

17654 posts in 3136 days


#15 posted 01-25-2010 12:29 AM

I am somewhat hesitant to mention this for obvious reasons :-)) , but what he heck!! I have been thinking it would be legal to run a 12-3 circuit on 20 amp breaker and connect a 220 volt 20 amp outlet and 2 120 volt 20 amp outlets for versatility with various machines. I suppose someone would try to use the 220 and 120 at the same time and trip the breaker :-((

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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