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Sawstop 110v vs 240v

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Forum topic by Trout121180 posted 02-27-2018 06:56 PM 1170 views 0 times favorited 24 replies Add to Favorites Watch
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Trout121180

44 posts in 224 days


02-27-2018 06:56 PM

So amoung a bunch of other things I am about to upgrade my SawStop 1.75hp cabinet saw from 110v to 240v. Not sure if this has been discussed here before. If so still having a little trouble navigating this site and I didn’t really even know how to look. Anyway if it has been discussed before if someone could point me in the right direction that would be great. If not my questions are basically what are the advantages to going up to 240v compared to 110v? Are there any disadvantages. Also just a quick background Sawstop sells a kit that allows you to upgrade to the 240v for $70. It has everything you need, Contactor box, 240v whip cord and supposedly really good instructions. Thanks!!!

-- Luke “I thought I was wrong once, but I was mistaken.” “If you wait till the last minute it only takes a minute.”


24 replies so far

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Loren

10477 posts in 3765 days


#1 posted 02-27-2018 07:00 PM

I think there’s an advantage in theory but
in practice not really. I’ve seen it explained
before.

View knotscott's profile

knotscott

8120 posts in 3492 days


#2 posted 02-27-2018 07:21 PM

It really depends on the specific circuit in question, and how it interacts with the particular motor. If there’s notable voltage loss on the 120v circuit due to any inadequacies, then 240v could help….but in theory so would an adequate 120v circuit. I like the fact that 240v splits the amperage across the two legs of your supply.

When I switched my previous 1.75hp saws from 120v to 240v, both showed notable improvement in startup speed and recovery from lugging ....one more than the other. If you have 240v available and can switch for $70, I’d go for it….little to lose, and some potential gain.

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

View YesHaveSome's profile

YesHaveSome

114 posts in 375 days


#3 posted 02-27-2018 07:34 PM

I converted my SS contractor saw to 220 a few months back. There were some quirks but it was, overall, pretty easy. The contactor box was supposed to come with instructions but it did not. There are some instructions in the saw manual but they werent thorough.

-- But where does the meat go?

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MrUnix

6887 posts in 2316 days


#4 posted 02-27-2018 08:02 PM

If the supply circuit is sufficient, you do not get any real advantage from converting from 120v to 240v. Internally, the motors windings only see 120v regardless of how you have it wired. The only real advantage is that you can use smaller wire for the supply line. The disadvantage is that you will be using a 240v plug that could probably be better used for another machine that can’t be run on 120v (ie: Anything with a 2+hp motor).

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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Craftsman on the lake

2804 posts in 3554 days


#5 posted 02-27-2018 08:16 PM

For a motor that size you’d probably not notice anydifference. I’ve got the 3hp one and I do have 220 using a #10 wire (overkill but I had a coil on hand). If you’ve got a 1.75 hp with a dedicated #12 or 10 wire to it and a 15 or 20 amp breaker you should be just fine. My older saw, a delta was like that and I had no problems.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

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Fresch

302 posts in 2037 days


#6 posted 02-27-2018 08:32 PM

Before this gets crazy:
A watt is a watt, 10 amps at 120volt is the same as 5 amps per hot wire on 240volt. = 1200watts.
Your motor was designed to run at the voltage on the motor name plate.

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Trout121180

44 posts in 224 days


#7 posted 02-27-2018 08:38 PM

Now that you mention it the lights do slightly dim when I start up the saw. But only the saw never noticed it on anything else. And also I just up graded from having only 30amps run out to my garage to now having 60amps so not sure if it still does it or not. Or if upgrading would even effect that or not. Electrical is not my thing. I should also state that one day I hope to swap out to the 3hp motor. Sawstop also sells a kit for that. It ends up costing you about $100 more than just buying the 3hp out right. Wasn’t sure if I would need the 3hp when I decided to buy my saw. And when the sales rep said I could always up grade later that was the deciding factor in going with the smaller motor. Anyone else here have a SS 175 and wis they had gotten the 3hp? I have a WWII and a forest 24th rip blade so I haven’t experienced any bogging down. I have burned some lumber here and there but I think that was more operator error.

-- Luke “I thought I was wrong once, but I was mistaken.” “If you wait till the last minute it only takes a minute.”

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Trout121180

44 posts in 224 days


#8 posted 02-27-2018 08:52 PM

Hey Fresch,
All of these parts come directly from SS. I don’t think they would sell me something unsafe or not designed for the motor. Or maybe I’m just Naïve in thinking that.

-- Luke “I thought I was wrong once, but I was mistaken.” “If you wait till the last minute it only takes a minute.”

View bbasiaga's profile

bbasiaga

1240 posts in 2112 days


#9 posted 02-27-2018 09:01 PM

I definitely notice a difference with the dado stack in. I have not cut a full height dado (not sure who does), but I haven’t met one I could not cut in one pass. Was not true on my older 1.75hp saw.

But generally I don’t think 3hp is absolutely necessary for most hobbyists. I just figured if I was buying a new saw, I would not want to upgrade it later.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

View Fresch's profile

Fresch

302 posts in 2037 days


#10 posted 02-27-2018 09:03 PM

I was trying to stop the 120v/240v will save you money from the power co. That the saw is better on 240v over 120v.

The parts from sawstop are factory parts so safety should be fine if you wire it correctly.

View clin's profile

clin

919 posts in 1113 days


#11 posted 02-27-2018 10:03 PM

I’ll just restate what knotscott said. At 240V, it will draw half the current it would draw at 120 V, given the same load on the motor. Half the current means there will be half the voltage drop to the saw. Will this matter? Not much.

Assuming your wiring is to code, the voltage drop is not going to be much more than 1 or 2 volts at full power. So I think at best you might get a few percent more maximum power out of the saw. I’d doubt you’d be able to notice.

The expense is minimal and if you like to tinker, then sure why not, but don’t expect much, if any change.

And I think MrUnix makes a good point that that 240 V plug may be better left available for some other machine that really needs 240 V.

If you really want to tinker with the saw, I’d put the $70 towards upgrading to the 3 HP. That’s a difference that actually means something.

-- Clin

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Trout121180

44 posts in 224 days


#12 posted 02-27-2018 10:33 PM

Hey guys,
Plenty of 240v outlets throughout the shop. To be honest while I had the electrician here I had him add another one just for the table saw. My 8” jointer has its own 240v 20amp circuit and plug. My compressor had it’s own 220v. And my planer has its own 240v 30amp circuit. 5hp motor on the planer!!!! Can’t wait to fire that bad boy up. Should be here tomorrow and is a nice upgrade!!!!

But overall great info. And I do like to tinker. Really trying to learn and do things myself more and more. Pulling the trigger on this one. Thanks for the insight.

-- Luke “I thought I was wrong once, but I was mistaken.” “If you wait till the last minute it only takes a minute.”

View TrentDavis's profile

TrentDavis

41 posts in 2352 days


#13 posted 03-13-2018 05:17 PM

Sorry I’m late to this conversation.

I work at SawStop so I can provide some further insight.

The real advantage, as I see it, when converting from 110 VAC to 220 VAC is that the motor is going to be drawing less amperage. What this means to the end user is that the motor will run a bit cooler but more importantly it will be able to hog through more material without tripping the breaker on the contactor box. Sure, the motor will get up to full speed faster when you pull the paddle (I can tell when I hear someones saw start if it is wired for 110 VAC or 220 VAC), but I don’t know anyone who’s bothered by a slower startup.

Upgrading to 220 VAC won’t give you more horsepower or make the saw any safer* but if you find that you are tripping the breaker on your saw then it’s a worthwhile investment.

  • Theoretically, if the saw was underpowered it might slow the blade down which can (again, theoretically) increase the chances of kickback.

-- SawStop Users' Group: https://www.facebook.com/groups/sawstopusersgroup/

View Fresch's profile

Fresch

302 posts in 2037 days


#14 posted 03-13-2018 07:03 PM



Sorry I m late to this conversation.

I work at SawStop so I can provide some further insight.

The real advantage, as I see it, when converting from 110 VAC to 220 VAC is that the motor is going to be drawing less amperage. What this means to the end user is that the motor will run a bit cooler but more importantly it will be able to hog through more material without tripping the breaker on the contactor box. Sure, the motor will get up to full speed faster when you pull the paddle (I can tell when I hear someones saw start if it is wired for 110 VAC or 220 VAC), but I don t know anyone who s bothered by a slower startup.

Upgrading to 220 VAC won t give you more horsepower or make the saw any safer* but if you find that you are tripping the breaker on your saw then it s a worthwhile investment.

  • Theoretically, if the saw was underpowered it might slow the blade down which can (again, theoretically) increase the chances of kickback.

- TrentDavis

If your saw on 120 volt draws 14 amps and on 240 volt it draws 7 amps per hot wire it is the same! 1680watts. It will be the same amount of heat, watts are watts. Why would it trip your contractor, unless you have the overload heater from the factory undersized, if you use one I didn’t look it up? If you trip breakers at the home load center then you have, incorrect wire size, bad breaker, or voltage drop due to length (see wire size), or a problem with the saw. The saw starts by electromagnetism it starts just as fast 120v or 240v. On 120v the wire needs to be #12awg copper, nothing else plugd into the same circuit. What is the factory wire size of your cord #14 or #12awg, #16? Manufacturers follow other codes for wire sizes for those that don’t know; that’s why your plug in heater cords feel like they are melting and hot or you look at your electric water heater, stove. Unless your motor changes horsepower at 240v I don’t understand your comments, what is your job title, I’m just a Master Electrician?

View BoardButcherer's profile

BoardButcherer

144 posts in 211 days


#15 posted 03-13-2018 08:01 PM


Sorry I m late to this conversation.

I work at SawStop so I can provide some further insight.

The real advantage, as I see it, when converting from 110 VAC to 220 VAC is that the motor is going to be drawing less amperage. What this means to the end user is that the motor will run a bit cooler but more importantly it will be able to hog through more material without tripping the breaker on the contactor box. Sure, the motor will get up to full speed faster when you pull the paddle (I can tell when I hear someones saw start if it is wired for 110 VAC or 220 VAC), but I don t know anyone who s bothered by a slower startup.

Upgrading to 220 VAC won t give you more horsepower or make the saw any safer* but if you find that you are tripping the breaker on your saw then it s a worthwhile investment.

  • Theoretically, if the saw was underpowered it might slow the blade down which can (again, theoretically) increase the chances of kickback.

- TrentDavis

If your saw on 120 volt draws 14 amps and on 240 volt it draws 7 amps per hot wire it is the same! 1680watts. It will be the same amount of heat, watts are watts. Why would it trip your contractor, unless you have the overload heater from the factory undersized, if you use one I didn t look it up? If you trip breakers at the home load center then you have, incorrect wire size, bad breaker, or voltage drop due to length (see wire size), or a problem with the saw. The saw starts by electromagnetism it starts just as fast 120v or 240v.
On 120v the wire needs to be #12awg copper, nothing else plugd into the same circuit.
What is the factory wire size of your cord #14 or #12awg, #16?
Manufacturers follow other codes for wire sizes for those that don t know; that s why your plug in heater cords feel like they are melting and hot or you look at your electric water heater, stove.
Unless your motor changes horsepower at 240v I don t understand your comments, what is your job title, I m just a Master Electrician?

- Fresch

Watts are watts but Volts are Volts. I’ve got daily experience working with all kinds of electrical motors, 120, 240, 460, single and 3 phase and a few years back we went and rewired every 120v motor in the shop to 240.

Why? We had one small shear that needed to be moved and it got moved to a corner of the shop where we didn’t have a 120 line in that corner to dedicate to it, but there was an open 240 single. After we rewired it the shear that used to always make more noise than any other machine it’s size was whisper quiet except for the mechanical action of the shear, you could no longer get the motor too hot to touch by running it nonstop, and the action was smoother. It all had to do with impedance in the motor itself and the effects of electrical frequency on induction motors.

People tend to forget that when you load down an induction motor it’s impedance sky-rockets. When you have a motor running off of 240 instead of 120 it smooths out the dips in the sine wave. That sine wave on AC motors is similar to the mechanical motion of a hammer drill or impact driver. At the peak of the 60hz wave the motor is receiving the full electrical current, but at the bottom of that 60hz wave the motor has no power, and thus no torque. By smoothing out the sine wave, which you are doing by adding a second sine wave juxtapositioned opposite of the first, you provide a more consistent torque profile which means the motor isn’t taxed as heavily under heavy loads, since it is no longer having to ramp up from 0 under load.

This is just my interpretation from what little I know about electricity and my firsthand experience.

But I’m not a master electrician, so correct me if I’m wrong. Feel free to get as technical as you want and cite anything you please. Anything I don’t understand I’ll look it up and appreciate the opportunity to learn.

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