# 220 V vs 110V Motor performance



## woodnthings (Jan 24, 2009)

I'm not an electrician, and I don't know if an "electrician" would know the answer to this but...here goes: The following quote from a recent post stated "I started out on 120v, and switched to 240v after using it a year. House wiring is impossible to compare but I noticed a *huge difference* by changing mine to 240v...."
I do know that the amperage required at 220V is half that on 110V,
so smaller guage wires can be run to power the same motor.
Watts (volts x amps) is watts except in California, where it's a riot!. 
So how is it possible for the *performance* to be better on 220V than on 110V? :blink: bill
BTW I have the Craftsman 22124 Hybrid which will operate on either voltage. That's the reason for this question.


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## freedhardwoods (Sep 7, 2008)

If his wiring was too small for the amperage draw on 110, That would cause a drop in performance. If you have everything installed properly, there isn't a noticable difference between 110 and 220.


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## clarionflyer (Apr 27, 2008)

Oh no, not this discussion again :laughing:.

If you're referring to me, I have an old house with old wiring. I loved my saw but it would dim the lights on start up, and the motor would struggle with tough cuts. I ran a devoted 240v line straight from the box which more than solved my problem - Instant start up's and cuts hardwood like butter now. 
I'm not an electric guy, but the difference was night and day. Everybody tells me it was the capacity pulling on insufficient shared house wiring which caused my initial problem. 
The last time this topic came up it was a 4 pager! Let's head it off before advanced math comes up :boat:.


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## rrich (Jun 24, 2009)

*Electricity 101*

Electricity 101

There is something called a voltage drop. In engineering circles it is also called an "IR Drop".

What this says is, the current in a wire multiplied by the resistance of the wire gives the voltage drop in the wire.

Assuming that the same wire that ran the motor at 110 volts is rewired to provide 220 volts there are two factors to consider. 
1) The supply voltage is higher and therefore any loss in the IR drop is a smaller percentage of the supply voltage.
2) The current needed by the motor is about half at the higher supply voltage.

Doing the math, the resistance in the wire is the same and the current is about half so the voltage drop will be about half in absolute volts. However the percentage of voltage loss will be about 1/4 that of the 110 volt circuit.

Further complicating the issue is that if a new circuit was installed, a larger wire size was probably used. (That is the norm for 220 volt circuits in this country.) This further improves the performance of the table saw. (Less IR drop over the larger wire.)

Clear as mud???


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## GeorgeC (Jul 30, 2008)

rrich said:


> Electricity 101
> 
> There is something called a voltage drop. In engineering circles it is also called an "IR Drop".
> 
> ...


Reads pretty good to me.

George


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## knotscott (Nov 8, 2007)

I noted quite an improvement by switching to 220v with my 22124 also...faster startups, faster recovery from bogging. 110v is supposedly theoretically the same as 220v, but it varies widely depending on the individual wiring circumstances of any given circuit, and the motor in question. FWIW, I didn't notice as much difference when I converted my former GI contractor saw to 220v. 

My usual suggestion....if you've got 220v available or easily available, make the switch if the motor is 1-1/2hp or greater (=/> 13 amp)...there's possible improvement, and no harm done (change the outlet and plug to a 220v). If you don't have 220v, but suffer from dimming lights, slow startups, easy bogging, etc., consider rewiring to 220v (also check alignment and blade/cleanliness). If you don't have 220v, and don't suffer any of the symptoms just described, don't bother. If you've got to rewire for any other reason, include 220v.


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