Is it worth converting to 220v?

[tbrad]

I am considering converting some existing stationary tools from 110v to 220v and would like some opinions on before and after performance. Will I get more oomph from the motors either during normal operations or when pushed to their useful power limits?

Specifically I have a Delta drill press with a 3/4 HP motor, Grizzly contractor tablesaw with 1.5 HP motor, PSI dust collector with 1 HP motor and Jet bandsaw with 3/4 HP motor. While I would love to upgrade some of these to better tools with more HP, it’s simply not in the budget for the foreseeable future. I have a new 150 amp subpanel in my shop with plenty of room for more circuits so that is not an issue.

 

[Wiley's Woodworks]

Up front disclaimer--in no way am I an electrical engineer or even an expert in electricity.

My practical experience is that 220v is used for machinery/motors that are > 3hp. This seems to be the tipping point when considering converting. I've seen 3hp SawStop table saws running on 110v handle everything that was fed into them. All of your tools are well under the 3hp tipping point. The most common tools that run on 220v are base mounted table saw, large band saw, 8"+ jointer, 15"+ planer, higher hp whole-shop dust collection system, and I've never seen a 220v drill press in a woodworking shop.

IMO you'll be better off saving up your money to buy your first machinery with 220v motors from the factory and adding the circuits at that time.

 

[Bas]

Short answer - no, running the same motor on 240V will not make it more powerful than running it on 120V. The exception is that if you have a significant voltage drop due to the distance from the panel to the tool or the circuit is close to being overloaded. In that case you may see an improvement. Since you have a new subpanel with lots of circuits, it doesn't sound like this will be the case.

You may be able to get better performance by upgrading the motor on your tools, e.g., go from 1.5HP to 3HP. This assumes the tool is sturdy enough to withstand any additional stress, e.g., table saw trunnions. For dust collector, adding horsepower probably won't do much unless you also increase the size of the impeller.

 

[Oka]

You will not get more power. However if the motors are high quality they will run smoother and the power factor would likely be improved. Look up power factor. These kind of question on motors are not a simple answer.
Ever wonder why one 1hp motor is 80bucks and another is 300?
Usually goes to the quality, duty cycle and it's efficiency rating

Look at the motor if the eff is 80% on a 1hp then the motor putts it .80hp
This is a long conversation.

So basically what Bas said

 

[bob vaughan]

In theory, its the same.
In practice, things may vary.
Its not the machine's motor, its the wiring that feeds the motor that can make a difference. There is less resistance on 220 circuits. The electricity flows easier. My experience is that if the motor is 1 HP (USA-made), then that's the stopping point for 120 volts.

In the 1970s I had a 1 HP radial arm saw. It would bog down. I swapped the wiring to 220 volts and it made a world of difference. Why? Because the 120 volt circuit had lots of other things on it and the new 220 circuit only had one thing on it.

The momentary inrush current of a capacitor start motor is about five times the motor's rated current. That can be a lot of flow on a busy 120 volt line.

 

[bob vaughan]

Knowing what size wire you have will help in your decision making. My old house has 14 gauge romex in the walls and some in the basement shop area so I know my limits and make wiring decisions accordingly.

 

[Echd]

Knowing what size wire you have will help in your decision making. My old house has 14 gauge romex in the walls and some in the basement shop area so I know my limits and make wiring decisions accordingly.

Yep, always size for the smallest gauge of wire you have in a run.

That said a 15 amp 220 would still have more useful horsepower than a 15 amp 110, so to speak. But it's really best just to do an entirely fresh run if you can. Convert some breakers to tandems if your breaker box can handle it.

In a perfect world a tool using 15 amps on 110 would simply use 7.5 on 220 and nothing else would change. I would not expect to see major differences by changing wiring unless you were blowing breakers constantly.

 

[tvrgeek]

Minimum code wire and a long run is not good for power delivery. Minimum code is what just keeps it from catching fire.
If in question, go ahead and re-wire the tool in question and see for yourself. I had no difference with my contractor saw or old RAS when I ran them on 110 vs 220, but they were on short dedicated circuits. Power tools should always be on a dedicated circuit and none of those crap back-stab outlets and never on an extension cord. Pay a couple bucks for commercial grade. If doing the wire work, go a gauge higher. Nothing wrong with 10 gauge wire to a 20A 110 outlet.

110 vs 220 resistance is NOT different. Wire gauge or length is. 110 on 12 gauge hot and neutral is the same resistance as 220 on Phase A and B on a 12 gauge wire. 14 gauge is useful for lights.
Yes, inrush is a big factor. My beef with minimum code.

Do note, a lot of consumer tools come with 15A 110 plugs when the draw more than that in steady state. Use 15/20 outlets. DeWalt planer is a good example.

3 HP band saw. Worth every extra dollar!

 

[Rwe2156]

Watts are watts. Bob is exactly right.

I've never heard of a motor over 2HP running on 110V.

Nothing wrong with 10 gauge wire to a 20A 110 outlet.

There is no reason to pay the extra money for bigger wire it's not going to get you any advantage.

Example: 10gauge/30A would be a dedicated circuit for a 5HP compressor. .

All my 220 machines are on one circuit. Maybe not code but it was done by an electrician and in 30 years the only time a breaker tripped was a bad motor overdrawing. Not a commercial shop with multiple machines runnng.

Many 110 circuits need to be dedicated: table saw, drum sander, dust collector for example.

 

[JimD]

The only advantage of the 220V circuit is the current will be lower. The watts will be the same. If you had to run a close to 2hp motor on a 14 gauge wire circuit (limited to 15A) you would need to go to 220V. But a 12 gauge circuit is fine at 20A (for a reasonable distance run) and will power the tools you mention. My shop has a 20A 120V circuit for tools, another 20A 120V circuit for the HF dust collector, and a 15A lighting circuit. I cannot run two large tools at the same time but I don't want to anyway. It is just me. I would make sure you have 20A circuits for at least your largest tools but would not mess with switching to 220V. It would add cost for no real advantage. I'm 68 and have been making sawdust for most of those years. I've never needed a 220V circuit (although I have used 220V tools in other shops).

 

[tbrad]

Thanks everyone for your responses. I will save my money and spend it on something else I’m sure!

 

[tvrgeek]

Dr. Bob and I will have to disagree on minimum specs vs appropriate engineering. There is more to it than tripping breakers. Maybe it's the 10 years I spent doing failure analysis . As far as tripping breakers, do understand a 15A breaker does not trip @ 15A. There are actual reasons for the NEC. Not obvious to the casual user. Newest code makes a lot of changes with regard to GFI. Just saying.

1 3/4 HP universal motor is about as big as I have seen run on 110. You can't lump all motor types together based on HP ratings and of course the totally bogus "peak power" advertising where a 15A 110 shop vac is claimed to be 5 HP.

 

[wbarnes]

Dr. Bob and I will have to disagree on minimum specs vs appropriate engineering.

Where do you think specifications and codes come from? Most of them are written or at least reviewed at some stage by an engineer and have a Factor of Safety (FOS) built in.

Of course you can always exceed code if that’s what you want to do, but realize that there are times (most of the time?) where just meeting code is perfectly acceptable.

 

[Oka]

Why electrical is sometimes confusing to grasp.

For those who want to have a quick reference book on all things electrical related, buy an Ugly's electrical reference book. they sell them at any elec supply or Home Depot or Lowe's. It costs about 15 buck, it is about 100 pages of reference and quick look up info essential to wiring most things residential or commercial. Very useful

Here is an example: Usually #8 is used to run up to 44-45 amp rated load. However, some county codes only allow 40amps. However, per the NEC you can have a momentary load (start load) can handle a max 55.3 amp load provided the connections and the wire are all rated 90c. Remember, start load is higher to get things going

So based on this a 40amp HVAC would be ok to wire with #8 because the start load would be 130%+/- or 52amp est. But ....... a elec oven, it would not because it is rated to run @ 50 amps and the start load would be 65amps @130%+/- start load. This all assumes you are running in copper, Alum typically requires one gauge thicker, so if you need #8 copper, you get #6 alum ......

Never run outlets in #14 awg always in 12 .......... most houses do not do this because of longer labor to install and higher material cost.

 

[tvrgeek]

Where do you think specifications and codes come from? Most of them are written or at least reviewed at some stage by an engineer and have a Factor of Safety (FOS) built in.

Of course you can always exceed code if that’s what you want to do, but realize that there are times (most of the time?) where just meeting code is perfectly acceptable.

10 years as a quality engineer doing failure analysis. NEC is based on safety, not performance.