220v vs 110 motor

[lago]

I am in the process of restoring a 1970 8" jointer that has a 3-phase 220v motor. Right now, I am assuming that it will work even though it has been sitting in a barn for the past 10 years or so.

My options are:
1) Get a variable frequency drive to convert 220v single phase to 3 phase.
2) Get a new motor 220v single phase or 110v.

If I go with the VFD or a single phase 220v motor, I still have to install a 220v circuit.

If I go with a 110v motor, no problem.

Motor in question is a 1 1/2HP @ 3450RPM.

Is there any advantage to a 220v vs 110v in a home shop situation?

Right now, I am leaning toward getting a 110v motor and selling the one that came with the jointer.

Your opinions?

Ken

[LCHIEN]

ken though there will be people telling you that 220V works better, as long as you have adequate wiring for 1.5 HP 120V motor (probably 15A, 14 or 12 ga. circuit with nothing else running on the circuit), you'll be fine. Any improvement a 220V motor would make is negligible, in the 1-2 percent region. and it will save you from having to put in a 220V circuit.

But, if you need a new circuit run, then you might as well run 220v and be able to put a couple of machines on the circuit.

[Prax]

The one thing that comes to mind immediately is the amp draw difference between the 2 motors. Check out Amp Draw of Electric Motors and see what you think.

[Uncle Cracker]

The 110V motor will pull twice the amps of the 220V motor. This is not a problem in a 1-1/2hp motor, provided the wire size is right and the distance is not too great. On larger motors, though, the wire size becomes hard to work with.

[Mr__Bill]

The one thing that comes to mind immediately is the amp draw difference between the 2 motors. Check out Amp Draw of Electric Motors and see what you think.

The 110V motor will pull twice the amps of the 220V motor. This is not a problem in a 1-1/2hp motor, provided the wire size is right and the distance is not too great. On larger motors, though, the wire size becomes hard to work with.

The Amperage is the same In the US a 220/240V circuit is just two 110/120V circuits perfectly out of phase. If a motor draws 10 amps it can be one 10 amp 120V circuit or two 5 amp 120V circuits. The only difference is in the size of the wire necessary to carry the load.

240V motors are often used to decrease the size of the wiring necessary and to help balance the load.

Bill
over here in the sun

[Uncle Cracker]

[B]

240V motors are often used to decrease the size of the wiring necessary and to help balance the load.

And the wire is smaller because...



wait for it...




the amps are less! 'magine that. Equal work (HP) with more voltage requires inversely less amps.



This is why a typical dual-voltage motor plate might read "Volts: 110/220, Amps: 28.0/14.0"... Doubling the voltage cuts the amperage required to do the rated HP in half.

[Mr__Bill]

And the wire is smaller because...



wait for it...




the amps are less! 'magine that. Equal work (HP) with more voltage requires inversely less amps.



This is why a typical dual-voltage motor plate might read "Volts: 110/220, Amps: 28.0/14.0"... Doubling the voltage cuts the amperage required to do the rated HP in half.

WRONG

The wire is smaller because the total amperage is split over two wires! In your example the total power used is the same. 14 amps of 220 is 14 amp on each leg of 110 or a total of, wait for it..... 28 amps.

Think of it as two water hoses each delivering 14 gal an hour or a total of 28 gal an hour. The same as a larger hose that can deliver 28 gal an hour by it's self.

Bill

[cabinetman]

WRONG

The wire is smaller because the total amperage is split over two wires! In your example the total power used is the same. 14 amps of 220 is 14 amp on each leg of 110 or a total of, wait for it..... 28 amps.

Think of it as two water hoses each delivering 14 gal an hour or a total of 28 gal an hour. The same as a larger hose that can deliver 28 gal an hour by it's self.

Bill

Lets say the motor is convertible. If run for 5 minutes on 110V (28 amps), or on 220V (14 amps), wouldn't the 5 minute run be cheaper electric wise on 220V because of less amps used for the 5 minutes?
.

[crokett]

No, it would not be cheaper because the power used (watts) is the same. W=V*A. I installed some electric heaters in the basement in February. The heaters are sized in watts. They sell 220V and 110V versions that have the same watt rating. The 220V ones have and advantage because they pull haf the amps so you can put more of them on a given circuit, but the power used (watts) is the same. It takes X number of watts to heat a room of a given size, whether you use 220V or 110V.

People think that less amps = less power consumed. It doesn't.

[woodturner]

The wire is smaller because the total amperage is split over two wires!

That's incorrect.

Power=volts x amps

Given a motor running at 10A at 110VAC (nominal), that motor will draw 5A at 220 VAC, which will generate the same 1 HP of power.

A circuit is a loop - the electrons flow out one wire and return on the other. With the 110 VAC circuit, the "hot" or black wire is the "input" side and the neutral or white wire is the output side, technically (thank Ben Franklin for that complication). However, we conventionally talk as if the electrons flowed out from the black or hot and into the white.

With a 220 VAC circuit, there are two hot or black wires. One functions as the output, and the electrons return along the other.

When we split a 220 VAC circuit to make two 110 VAC circuits, we use the neutral as the return path. There is a transformer on the house side of the utility mains that provides a neutral that is a mid point voltage. We then ground that point to earth ground to keep it near 0 volts.

[woodturner]

1) Get a variable frequency drive to convert 220v single phase to 3 phase.
2) Get a new motor 220v single phase or 110v.

A 1.5 HP motor should draw around 15A at 110 VAC (nominal) or 7.5 A at 220 VAC (nominal).

The advantages of your existing motor would be that it is likely a more efficient motor with more mass, so it's likely to run quieter and heat up less - but a phase converter is required to run it.

The advantages of a newer motor would be that it is single phase - but may be less efficient, cost more, heat up more, etc. If you go with a universal type motor, you may be able to save some money and electricity, provided that you don't regularly load the motor to its capacity.

[jschen]

WRONG

The wire is smaller because the total amperage is split over two wires! In your example the total power used is the same. 14 amps of 220 is 14 amp on each leg of 110 or a total of, wait for it..... 28 amps.

Think of it as two water hoses each delivering 14 gal an hour or a total of 28 gal an hour. The same as a larger hose that can deliver 28 gal an hour by it's self.

Bill

That doesn't sound right to me at all. We have power = volts * amps.

Using that motor of Volts: 110 and Amps: 28 then

P = 110 * 28 = 3,080 watts

For the Volts: 220 and Amps: 14

P = 220 * 14 = 3,080 watts

Less amps same power. I don't think Bill is right saying that the 220V line is still providing 28A overall.

[cgallery]

If you stick w/ the three phase motor, and get a converter, you can dial-in the RPM's. I read somewhere the other day where someone did that and had a reason why it was valuable to him (seemed plausible).

I see the value in a bandsaw or drill press, but can't remember why he liked doing it on the jointer.

I'll try to find it again.

[LCHIEN]

Sorry, but Mr. Bills statements are very confusing and some of them are very wrong.
For all practical purposes, the power and hence cost of operating the a 110/120V motor or a 220/240V motor will be the same, for the same work.

The 110 will take twice the amps of the 220V motor to do the same work. But the power is the same.

If nothing else is on the line then you have no problem and operation is the same.

But if you want to share the line with another high power tool running simultaneously, then you must either provide another line (110V) or you can run both the tools on a single 220V line since the ampacity of the tools is halved itr will still be within the common 15 or 20A of a household branch circuit.

Once the tools get over 1.5HP (not the OP's case, though) you can't even run enough amps on a common 110 line to handle the rated amps so a 220V line is required.

[Mr__Bill]

Sorry, but Mr. Bills statements are very confusing and some of them are very wrong.

You are right. What I said is confusing.

But if you use a clamp on volt meter on a 220V line with a motor drawing 8 amps each line will show 8 amps. Because each line is perfectly out of phase with the other at any one time only 8 amps are drawn across both lines. However, to use jschen's example slightly modified:

P = 110V * 14A = 1,540 watts Leg 1 of the 220 circuit
P = 110V * 14A = 1,540 watts Leg 2 of the 220 circuit

Taken together we can say we have two 110v circuits together drawing 28 amps.
P = 110V * 28A = 3.080 watts

Or one 220V circuit drawing 14a
P = 220V * 14A = 3,080 watts

We use the latter because as stated above with each 110V circuit being perfectly out of phase with the other at any given time only 14A is being drawn across both lines when measured at the same instant ergo, wire rated for 14A is needed. However, I contend that since we do not have 220V between a singe line and ground but have two 110V lines that each are providing 14A for a total of 28A or 3,080W. We use the calculation of 220V times 14A (which is really the same as 110V times 28A) to reach the 3,080W because if we did not electricians would never be able to figure out what size wire to use.

Therefor, in the US with 220 being really two 110V lines (we are not talking about 3 phase here) the same total amps are drawn if we measure across each line independently.

Bill
and the airplane on the conveyor will take off.