Any benefit in running my bandsaw on 220 instead of 110?

[rudy de haas]

I just texted my friends, who are commercial electricians, set power poles, are certified, own their own Company here, etc, and they both say go with the 220 cause first, less power consumption, the second is "potentially more torque, in the sense of not binding or dragging when cutting through knots or tough lumber..."

Hope that helps

David:

This is wrong with respect to standard power circuits, correct with respect to 3-phase power. A 3 phase motor does have higher torque and lower heat loss etc, Mike's Grizzly band saw does not.

There are technical gains in using 220/240 (most of the time these terms describe the same actual line voltage), but they are generally too small -things like lower power losses due to wire heating, marginally high field densities etc. - to notice without instrumentation. (One exception: if your tools are far from fixed wiring, a 220 cord can be longer with lower power losses than a 120).

Both my planer and my bandsaw came as 110/220 and I opted for 220 for both - but only because wiring my garage for 220 gave me access to higher power tools like the table saw and jointer and I like consistency.

[Phil Thien]

If you learned anything, it should be to stop saying 110; it is simply wrong. If you ever get 110v from your utility, you should complain immediately because it is way out of the allowable specs. It is much like referring to 120 grit sandpaper as 110 because that is what your father called it.

National Steady State Voltage Regulation Standards specify 114 to 126 on legs, with utilization of 104.4 to as high as high as 127.2.

So if you're getting 110v at the service, it is too low. If you're getting 110 (or as low as 104.4) at a receptacle, it is within range.

[John Lankers]

The fact that you were tripping the 20 amp circuit breaker is a definite indication that something was wrong. A 1.5HP motor would draw somewhere in the range of 12-13 amps at 120V when the motor is fully loaded. On startup, it would draw significantly more for a very short time. Your's is drawing more than 20 amps long enough to trip the circuit breaker. Check the voltage at the motor when you startup the motor and see if it's going down an significant amount. If so, you have a wiring problem.

With an adequate circuit, a motor will perform exactly the same on 120V or 240V.

Mike

[Of course, it could be your motor. At 240V you will draw half the amps. And I'll bet that 240V circuit has a bigger breaker than 10 amps. Your motor may be drawing a lot of amps at startup but your 20 amp breaker (I'm guessing on the size) on the 240V circuit is big enough that it doesn't trip.]

First of all my apologies to Mike Dowell for highjacking his thread.

Mike, you're guessing right it is the cheap chinese import that is the problem, whether Grizzly, Shop Fox, Craftex or G I the motors are all the same, these motors are not of the greatest quality.
I hooked on my Amp meter when the motor was still wired 120 and the amps spiked so high for a split second I couldn't even get a reading before the breaker tripped, after rewiring the motor to 240 everything is just fine (7 Amp on startup with blast gate open) and it runs smoother than it ever did on 120. Is it worth having the motor checked out and maybe rewired - no, unless it happened during the warranty period. I doubt this would happen with a Baldor, Leeson or Siemens motor. You get what you pay for .

[Jason Roehl]

National Steady State Voltage Regulation Standards specify 114 to 126 on legs, with utilization of 104.4 to as high as high as 127.2.

So if you're getting 110v at the service, it is too low. If you're getting 110 (or as low as 104.4) at a receptacle, it is within range.

Good info here. It should be noted that "110/220", "115/230" and "120/240" have all been nominal voltages--that is, they are "named" that voltage, but may vary from it. 110/220 is purely obsolete--it's mostly old-timers that use those nominal voltage terms. 115/230 is still, as far as I know, used as a nameplate rating on motors, and I don't think it was used for line voltage naming in the U.S. 120/240 is the current (rimshot) nominal voltage in the U.S. My current (another rimshot) house seems to get a pretty consistent 120-121V when I've bothered to measure it, whereas my previous house got a pretty solid 125V at the receptacles. The two houses are 15 miles apart, served by different utility companies.

[Lee Schierer]

National Steady State Voltage Regulation Standards specify 114 to 126 on legs, with utilization of 104.4 to as high as high as 127.2.

So if you're getting 110v at the service, it is too low. If you're getting 110 (or as low as 104.4) at a receptacle, it is within range.

Be sure your meter being used to measure the voltage is accurate. There are some meters out there that are more of voltage indicators than they are precision measuring devices.

[Mike Cutler]

So ~ that back in the 50's electrical devices came labeled 110-120 or in some cases 115. The grid seems to be a little more robust these days.

Mike

They still do. You can go to any big box store and find duplex receptacles, devices, and enclosures that are stamped for 115vac.


For info general information;
106 vac, wide spread distribution reference, would be the threshold of what is known as "Degraded Lines", and your utility company would begin breaking out their " Brownout" procedures.

[Jeff Raefield]

As an Electrical Engineer (who happens to love woodworking), I read this with interest. It's especially interesting to hear "electricians" repeating the myth that 240V "saves energy". Watts = watts = watts... a 1HP motor is 746 watts, the voltage does NOT play into that. The CURRENT changes by the ratio of the voltage change, but the watts stay the same. Watts = power, energy = power over time. So if the watts stay the same, so does the energy used.

There IS, however, an advantage to connecting to 240V, based on the power rating (HP) involved. The practical limit for a basic 120V 15A rated outlet is 1-1/2HP, or about 1200W. Any more than that and a standard 15A circuit breaker will likely trip on the starting current of the motor. In addition, when you push a piece of wood into the saw and load it up, the blade slows down, the voltage will drop because the current surges to try to re-accelerate the motor. The voltage drop then causes the motor accelerating torque, the very THING you need to get it back to speed, to drop by the SQUARE of the voltage drop. So if the load causes the voltage to drop to 90%, that makes the accelerating torque drop to 81%, which makes it even WORSE. By using 240V, the current is 1/2 from the get go, so it less likely to cause a voltage drop when the motor is loaded. The saw APPEARS to be stronger because it re-accelerates faster. It's really the same HP of course, just less AFFECTED by the problems of voltage drop under loading.

At 1/2HP and under, you would never notice the difference. 3/4HP is a toss up, 1 to 1-1/2HP is where you will notice it the most.

As to voltage standards:
There are two voltage "standards": Distribution Voltage and Utilization Voltage. Distribution Voltage is what the utilities supply, Utilization Voltage is what the equipment mfrs (motors mainly) manufacture to. So the Distribution Voltage standard in the US, per ANSI C84.1 (American National Standards Institute) is 120/240V for residential single phase services. The Utilization Voltage that corresponds to this is 115/230V, as promoted by NEMA MG-1 (National Electrical Manufacturer's Assoc.). This lower Utilization Voltage design spec allows for an EXPECTED voltage drop from the utility transformer, where they are measured, to the motor terminals, where you use it. The Distribution Voltage can vary by +-5% maximum, the Utilization Voltage rating is expected to allow for +-10% minimum. In days long gone by, every utility was putting out their own distribution voltage standards. 110V goes back to the days of Thomas Edison at the turn of the previous century, who picked 110VDC for his first electric light distribution system in New York City for a long list of reasons and compromises. When Westinghouse and Tesla decided to try to compete with him by distributing AC over longer distances (from Niagara Falls), they used 110VAC because it was what Edison's light bulbs used already (incandescent lamps don't know AC from DC), and the popularity of indoor lighting without gas was what drove electrification in those early days.

That was boosted to 120V during the depression when one of the WPA projects was to "electrify" farmhouses in order to boost food production, with what was called the REA, Rural Electrification Administration. The REA had mobile electricians running all over the country for a decade in the 30s wiring up farms, but they didn't want them carrying around a bunch of different equipment based on what one utility supplied verses another. They settled on 120/240V, hoping to get the utilities to standardized to match it, which for the most part worked. The Edison Institute published expected Distribution Voltage standards after WWII (1949), then ANSI made them official in 1954. Although technically ANSI standards are official, there is no over-arching utility organization dictating compliance and it's not government mandated. There is however one large group organization called EUSERC that constitutes 14 of the largest utilities in the country, and that drives a lot of willingness to conform because EUSERC dictates adherence to ANSI specs. But if a legacy system is already installed at a different level, it's way too expensive for them to rip and replace, so a lot of areas with older systems are "grandfathered" into voltage levels that appear to be non-conforming to ANSI specs. That's another reason why the Utilization Voltage design spec is allowed to be +-10%.

Bottom line: you can call it 110, 115, 117, 120, whatever you like. It all means the same thing in the long run.

[Phil Thien]

As an Electrical Engineer (who happens to love woodworking), I read this with interest...

Very good post but I have a follow-up Q:

Why are utilization rates specified as +/- 10%, why not +0/-10%? Under what circumstance(s) would utilization rate be higher than distribution?

[David Ragan]

At 1/2HP and under, you would never notice the difference. 3/4HP is a toss up, 1 to 1-1/2HP is where you will notice it the most.

Thanks for postiing that Jeff! I could never do the EE thing....way way too much math.

In all fairness to my electrician friend(s) immediately after they texted their answer in regards to the advantages (real or perceived) of 220/240, etc.........Immediately after he answered, he asks......how much HP is the motor in question?, and I blew him off, telling him I'm not in a hair-splitting mood.

probably if I told them I was going to post to a world-wide forum of ww hair-splitters, I probably would have gotten a more technical answer-to give to you all.

Shame on me.

[Jeff Raefield]

Very good post but I have a follow-up Q:

Why are utilization rates specified as +/- 10%, why not +0/-10%? Under what circumstance(s) would utilization rate be higher than distribution?

Because utility distribution tends to climb above their normal range at night when large loads shut down. They have regulation, but it is not instantaneous. Also, if you have a motor designed for 230V and the distributed power was 232 at the transformer but dropped to 206 at your motor terminals, it's within range from the utility standpoint. So if YOU compensate for it by changing YOUR transformer taps to get you back to 230, then THEY go 5% high at night, your changed voltage climbs to 260+ and you start frying things. Residential users can't do that of course, but industrial users can, and the rules have to cover everyone.

[Todd Willhoit]

Here is the ANSI table showing voltage levels as Jeff has described.
C84.1(1989).jpg

[Eric Schmid]

Jeff, your succinct explanation got me thinking about single phase motors on a three phase system. As I understand it 120V is available between one hot and the neutral on a three phase system and there is 208V between two hot wires. As I recall a couple of old Baldor motors in my shop can be wired 115/230/208V. Some newer motors are 115/230V only. What is the optimal voltage for single phase motors on a three phase system? For example, aassuming the motor is limited to 115/230V would it be best to connect it at 115 or 230V? Considering the logic you just laid out it seems like 115V is optimal for dual voltage motors (i.e. 1.5HP or below with no 208V option) on a 3PH system. What is the effect on higher HP motors in this scenario? For example, 2+HP motors wired for 230V but only receiving 208V?

[Johnnyy Johnson]

Not read above posts, but the more machines you have on 240 volts the more balanced your electrical panel will be. For example if you have a lot of 120 lights on one circuit, and start running a 3hp 240 volt planer steady the difference in total load will go through the neutral. If you have 10 amps 120v on one phase and 8 amps 120 volt on the other phase there will be around 2 amps on the neutral. Therefore, the greater the imbalance between the 120 volt circuits the more amps through the neutral. The more 240 volt machines the better. BTW ohm's law proves no watt savings between 120 and 240.

Lets not get into the 3 phase machines, then power factor and square root plug into the calculation.

[Mike Henderson]

Not read above posts, but the more machines you have on 240 volts the more balanced your electrical panel will be. For example if you have a lot of 120 lights on one circuit, and start running a 3hp 240 volt planer steady the difference in total load will go through the neutral. If you have 10 amps 120v on one phase and 8 amps 120 volt on the other phase there will be around 2 amps on the neutral. Therefore, the greater the imbalance between the 120 volt circuits the more amps through the neutral. The more 240 volt machines the better. BTW ohm's law proves no watt savings between 120 and 240.

Lets not get into the 3 phase machines, then power factor and square root plug into the calculation.

There's really no problem with having current flow in the neutral - at least none I can think of.

Mike

[Johnnyy Johnson]

I think the real point is being missed. The more 240 volt machines you have the better balanced the rec panel is. A good balanced panel will have very small amount of amps on neutral. Mostly when a router or lights (120 ) causes the imbalance. Ohm's law is the same on single phase 120 / 240.

Eric...the 208 motors are mostly used in factories. It takes a difference step down transformer to develop the 208....480/208