Bandsaw re-volt - is this worth it?

[Prashun Patel]

I'm moving my 14" G0555 Grizzly bandsaw to my new 'shop' which has 220v available. I'm thinking to rewire it from 110 to 220v? The operation's pretty simple: new cord and a couple wire changes in the switchbox. Is it worth it?

90% of what I cut is 2" or less. However, I do occasionally have to cut harder wood in the 3" - 6" range. Will the lower current draw result in an easier cut?

I'm also thinking to install riser blocks eventually.

My instinct says that it'll only help when I need more power than I'd be able to deliver on a 15a/110v circuit - which I have yet to encounter.

[Dennis Ford]

If your new shop has adequate wiring, there would not be much advantage in going to 220v. An easy to tell would be to plug a lamp into the same outlet as the saw. If the light dims when the saw starts, then it is likely worthwhile to go to 220v.

[Will Overton]

Going to 220v gives no additional power.

[Steve Bigelow]

I found that when I rewired to 240V from 120V that my saw started up (came to full speed) much faster.

That means that it wasn't getting enough starting current, which in turn was stressing out the motor. (Double the voltage = half the current).

You probably won't notice a difference while sawing, but I'm convinced the motor will last longer.

[Prashun Patel]

Yep, I know that there's no power advantage at low amps; the higher voltage just allows the same power delivery at 1/2 the current draw.

I just thought that a high voltage line can deliver more power at higher loads, which would cause a 110v line to trip. I guess I'll wait until I start to encounter such situations before I rewire.

[John Mark Lane]

I find the whole topic REVOLTING!

[Will Overton]

I found that when I rewired to 240V from 120V that my saw started up (came to full speed) much faster.

That means that it wasn't getting enough starting current, which in turn was stressing out the motor. (Double the voltage = half the current).

You probably won't notice a difference while sawing, but I'm convinced the motor will last longer.

I noticed the same thing when I ran dedicated 12ga / 20amp lines to my larger tools.

Too often folks (I've done it) get that new tool home and plug it into the 15a outlet that's on the same 14ga line as the overhead lights, the radio and whatever else. Then they run a dedicated 240v line and say wow!

Nothing wrong with 240v, particularly if you already have it, but it is no better than a properly wired 110v line.

[Bruce Page]

Going to 220v gives no additional power.

Bingo!....

[Steve Bigelow]

I noticed the same thing when I ran dedicated 12ga / 20amp lines to my larger tools.

Too often folks (I've done it) get that new tool home and plug it into the 15a outlet that's on the same 14ga line as the overhead lights, the radio and whatever else. Then they run a dedicated 240v line and say wow!

Nothing wrong with 240v, particularly if you already have it, but it is no better than a properly wired 110v line.

I wired my shop myself and used 12 gauge for my 120V outlets. Running the bandsaw at 240V still started up better. And this is only a 1.25HP bandsaw motor. The in-rush current is huge, though.

Getting more technical... 240V does give a negligible power increase.


Ignoring power factor, RMS, etc for simplicity....
Your standard 14 gauge wire is rated at 2.525 ohms per 1000 feet.



To make the math easy, lets assume the wiring to the bandsaw from the breaker panel is 33 feet. So, we have 0.2525 ohms per 100 feet, or 0.2525/3=0.084 ohms per 33 feet.
A "standard" 1.5HP motor is generally rated at about 15A / 120V.
So, your power loss is I^2*R, or 225*0.084 = 19W, or 0.025HP. At 240V, this loss is cut to 4.7W, or 0.006HP. Thus, technically, you have 0.019hp more at 240V. :)
Obviously, this will change as your motor HP increases / decreases, and is very negligible for any motors we may be dealing with.

[Chip Lindley]

I guess I'll wait until I start to encounter such situations before I rewire.

You will certainly notice when the need arises to change a machine to 230V for easier starts, or less breaker trips under heavy load!

High voltage made an almost unusable Rockwell contractor's saw into a class act! Amazing difference!

[Van Huskey]

Unless you have a voltage drop issue with your 120V circuit you will not notice anything different by changing to 220V.

[Will Overton]

Ignoring power factor, RMS, etc for simplicity....
Your standard 14 gauge wire is rated at 2.525 ohms per 1000 feet.


Which is why I said I ran 12ga wire and 20 amp breakers, instead of 14ga. It's the supply wire, not the voltage that makes the difference. I've never tripped a breaker since doing this.

[Nelson Howe]

I had always heard that it's easier on the motor, though. Not true?

Nelson

[Peter Quinn]

All the 110V circuits in my shop are 20A run with 12awg wire. Lighting is on a different circuit from any machinery or power tools. I used to run my 1 1/2HP BS on a dedicated 20A circuit which was a short home run to the panel, it had a built in light, no dimming, no hard starting, I loaded it to its maximum, no issues. I see no advantage to running a tool that small at 220V unless the wiring requires it, If you had old 15A lighting circuits of dubious origin for powering tools and were going to run a few new circuits at 220V for your machinery AND wanted thus to be able to run your BS at that voltage to take advantage of that, I could see some logic in rewiring it. But if you have good 110V power available its of little value.

You might make a plausible argument for converting a heavy load motor that sees nearly continuous use to 220V versus 110V, but that doesn't describe most bandsaws in a non industrial setting.

[Steve Schoene]

Not true. As long as house wiring for 120v circuit is satisfactory.

[Steve Bigelow]

Which is why I said I ran 12ga wire and 20 amp breakers, instead of 14ga. It's the supply wire, not the voltage that makes the difference. I've never tripped a breaker since doing this.

And why I did the same, if you re-read my post....

Still made a difference on start-up going to 240V from 12 gauge 120V.

As I mentioned earlier, the biggest difference is that your motor is going to last longer. I know the Delta 1.5hp 120V dust collectors have a bad history of blowing their motors too soon.

[Thomas love]

Just curious , what is 220 v good for?

[Will Overton]

Just curious , what is 220 v good for?

Interesting discussions on woodworking forums. :D

It's also necessary, in general, for motors above 1.5/1.75hp.
Since wire size is determined by amperage drawer, you can use smaller gauge wire when using 220v. In a large installation that can save some $$$.

[Dave MacArthur]

Switch it to 240V, but for none of the reasons above. Sooner or later you're going to want to flow more power to your shop, you're probably on a sub-panel or will be sometime, and by wiring it to 240 V you cut the Amps in half. The limiting factor for how many machines you can run at once is the amps pull of them all running. Set yourself up for success on having:
lights on, bandsaw running, dust collector sucking, air filter running, your air compressor kicking on during it all, and stepping away to cross cut a board on your SCMS for a sec.

The only advantage to having 120V wiring on your motors once you've got 240V in the shop that I can see is you may have more plugs available, and several (arguable) small advantages you may find with 240.

Of which more power to the saw is of course not one of them.

Besides, how can you drink a beer with the other fellers and feel good about yourself telling them, "I got Daisy over there wired up 120V, you think I should get 'er set up to 240 like you got your Butch?" "110, 220, whatever it takes!".

[Thomas love]

Thanks Will,

[glenn bradley]

IF they billed by amps instead of watts I would convert everything I could ;). I have 110v and 220v readily available. I have the tools that require it on 220v and some just because I didn't feel like running a new outlet (same cord was in spec and I had the plug).

My TS I have run both ways and see no difference on a properly provisioned circuit. Its been 110v for a couple years now but, may change back if I re-organize and it ends up near a 220v outlet. On the other hand, one more re-org and I'll ned to run a few more circuits :rolleyes:.

[Prashun Patel]

I read a good article in a back issue of ShopNotes that addressed this issue.

The bottom line (from them) is that it reduces the strain on motors in situations where the load on the circuit is high.

I do notice that when using my jointer, I get a slight dimming of the sole worklight that I've installed on this circuit. So, I'm gonna rewire the motor for 220.