Question about HP on lathes

[dennis kranz]

Thanks to another thread I see a differance in horsepower. What is the differance between Jet 1642 1 1/2 HP 115 Volt 1 Phase compared to Grizzly G0632 1 1/2 Hp 220 Volt 3 Phase. Is one more powerful meanlng stronger? Has anyone here used the Grizzly?
Now be nice to me and make the ansewers nice and simple.
Dennis

[Nathan Hawkes]

Dennis, I'm not going to be nice to you. :D J/K. I haven't used the grizzly, but the turning club I belong to has the 1642 1.5HP model JET. The Jet has a 3 phase motor that is powered by a VFD (variable frequency drive), which is more or less a solid state, microcomputer version of a rotary phase converter, with the added benefit of variable speed. I'm not familiar with the grizzly, but if it is a variable speed model, chances are it is using a VFD to power it. Both models should get similar power if they are the same HP. To make things even less simple, I didn't know that you could power a VFD with 115V current. I hadn't noticed what the turning club lathe plugged into. I'm waiting on delivery of a 3HP VFD to power the used 3ph motor I got a while back :D:D:D:D:D.

Edit: As I understand it Dennis, if a non-VFD controlled motor is hooked to 3ph power, when compared to a motor that is powered by 1ph power, the 3ph motor will have more torque, even if HP is the same. I'm no expert, but I don't think there is any significant amount of torque loss when powering a 3ph motor with a VFD using 1ph current to generate the 3ph output to the motor.

Hopefully that's simple enough. I only feel like I have a basic grasp of 3ph current--enough to be dangerous. I have someone helping me wire up the controller & motor.

[Bob Hallowell]

Dennis,
they both have 1 1/2 3ph motors. the jet has a 115v to 220v 3ph varible freq drive and the grizz has a 220v 3ph to 220 1ph vfd. they should have the same power. But that being said the jet has been proven to be a good lathe, I haven't heard anything on the grizz

Bob

[Michael Faurot]

In general, a motor that works at 220V vs 110V pulls less current because there's more voltage available. Based on the specs of some other 1-1/2 HP motors running at 110V you need about 18A, which means it needs to be on at least a 20A 110V circuit. Plus that machine will need to be the only thing pulling current on that 110V 20A circuit. If that same motor will run at 220V it'll only need 9A (half the amperage).

In the particular case you mention, there's also the difference between single phase and three phase. I don't particularly understand all the specifics of three phase power, but I do know that unless you live an area[1] that your power company can provide three phase you'd need to get a rotary converter that can turn 220V single phase into three phase power.

Ultimately the ability to attain more electrical horsepower requires more amperage. 110V is typically limited to about 1-1/2 HP. I know Grizzly makes some 110V 2HP stuff, but I'm not sure if that's either A) believable or B) would require more than a 20A 110V circuit. To realistically get at least 2HP you're going to be looking for a single phase 220V motor.


[1]: This would be an industrial area or sometimes in rural/farm areas.

[Gordon Seto]

Some companies use inflated numbers. It was a common practice in wet and dry shop vacuum, electric chain saw, air compressor.
The Grizzly G0462 claimed to have 2 HP on 110 Volt single phase on 15 Amp.

Guys knowledgeable about electricity said that was impossible.

[Bob Hallowell]

Some companies use inflated numbers. It was a common practice in wet and dry shop vacuum, electric chain saw, air compressor.
The Grizzly G0462 claimed to have 2 HP on 110 Volt single phase on 15 Amp.

Guys knowledgeable about electricity said that was impossible.

I agree with that but this is different. these are both 1 1/2 3ph motor controled by vfd's I don't think they are overinflated. You can buy a vfd at factorymation.com with a 115v in 220 3ph out. Plus the grizz is 220 in.

Bob

[robert hainstock]

when a coil of wire is moved through a magnetic field, a sngle phase voltage is generated. When two such coils of wire are moved through a single magnetic field, two voltages, (two phases) aare generated. three equals three etc. 110 voltage is single phase. 220 voltage is split phase or two times 110V, still single phase, but twice as much power available. 3 phase, (three coils and a magnet)is much more powerful because three coils of wire are moving through the magnetic field 120 degrees apart. This is much more powerful and provides much smoother running. I don't expect this helps much, but I would go with the Jet based on what I have read here on the creek.:eek: :mad::)
Bob

[Gordon Seto]

I agree with that but this is different.

My point is if the company has found to be untruthful in the specs sheet, how do I know which number is not inflated? If we reward the liars; they will never clean up their act.

[scott schmidt grasshopper]

just pulled out my grizzly catalog and the 632 is powered by 220v 1 ph not 3 ph
3 phase power is an oddball for residences and normally avalible only at farms or industrial sites.
the original question is . they both should have the same power
the griz will require a 220 v outlet and will be cheaper on the electric bill.

[Wilbur Pan]

To be a bit nitpicky: the motor on the Grizzly and Jet lathes both are 3 phase 220V motors plugged into VFDs, which is how you get your variable speed control. The VFDs are then plugged into the wall, which is single phase 220V.

So they will run in your home workshop if you have single phase power, thanks to the VFDs, but the motors themselves are 3 phase.

One other nitpicky point: you don't save on your electricity bill by using 220V service. Your electricity bill is calculated not on amps, but on the wattage you use, which is volts x amps. Even though you're drawing half the amps on a 220V circuit, the voltage is doubled, so it's a wash.

[Nathan Hawkes]

One other nitpicky point: you don't save on your electricity bill by using 220V service. Your electricity bill is calculated not on amps, but on the wattage you use, which is volts x amps. Even though you're drawing half the amps on a 220V circuit, the voltage is doubled, so it's a wash.

Though they definitely use the same amount of energy, no matter what the voltage, the motors that I've used over the years operate with much, much more torque when using 220v vs 110v. This could be in part due to the lower current used with 220v vs. 110v; you can use a thinner wire to deliver the same energy. This is one of the main reasons for 3ph power; more torque, less amperage draw on each lead.

[charlie knighton]

One other nitpicky point: you don't save on your electricity bill by using 220V service. Your electricity bill is calculated not on amps, but on the wattage you use, which is volts x amps. Even though you're drawing half the amps on a 220V circuit, the voltage is doubled, so it's a wash.


thank you very much, Wilbur, that is a misconception that i have heard every since i started turning :cool:

[Mike Henderson]

Though they definitely use the same amount of energy, no matter what the voltage, the motors that I've used over the years operate with much, much more torque when using 220v vs 110v. This could be in part due to the lower current used with 220v vs. 110v; you can use a thinner wire to deliver the same energy. This is one of the main reasons for 3ph power; more torque, less amperage draw on each lead.
This is the age old argument about 220V supply for motors and 110V supply.

Given that you have a proper circuit* feeding the motor in each case, there is no difference in operation between 110V and 220V. Operation at 110V will require twice the amps but that does not affect the power, torque, heat, or anything else.

Also, HP is defined as torque times angular velocity (essentially RPM) so if two motors are rated the same HP and have the same RPMs, they will, by definition, have the same torque.

I think the reason people think they get more power (or torque) from running a motor on 220V is that they had a 110V circuit which had excessive voltage drop.

Mike

*A proper circuit is defined as one which supplies rated voltage under all conditions of normal operation.

[John Davidson]

It doesn't matter if the motor is wired for high voltage or low voltage the same torqure is produced. Motors that are able to run high or low voltages have two sets of coils for each phase. In the low voltage configuration the coils are wired in parallel so that each coil sees the line voltage. In a high voltage configuration the coils are wired in series so that the line voltage is divide equally between the the coil set for a given phase.

Also, AC induction motors are HP rated at loaded speed. This means that if the HP rating on the motor is 2hp with a rated speed of 1720 rpm the motor should deliver 2 hp at the speed of 1720 rpms. Thats the standard for single or three phase induction motors.

[Richard Madison]

So Dennis, did you follow all that? Bottom line is that if the published ratings are honest, there is no difference. One and a half hp is one and a half hp no matter where it comes from.

[Dick Strauss]

Two things to note...

Not all 1.5hp motors are rated the same way. One might be rated for 1.5 hp peak while another might be rated for 1.5 hp continuous and 2 hp peak. The lathe tests routinely show significant differences in actual motor torque. As an example, my Delta 3/4 hp motor definitely has more than 50% more torque than a Jet 1/2 hp motor (from the mini).

Neglecting any motor differences, you do save money by running 220V instead of 110V. However, it is very small and on the order of 0.4%-1.3% savings for that circuit only...
0.4% savings for a 5A/220V vs a 10A/110V through a 10g 50' copper wire
0.6% savings for a 5A/220V vs a 10A/110V through a 12g 50' copper wire
0.8% savings for a 10A/220V vs a 20A/110V " a 10g 50' copper wire
1.3% savings for a 10A/220V vs a 20A/110V " a 12g 50' copper wire
1.2% savings for a 15A/220V vs a 30A/110V " a 10g 50' copper wire
(20A is the maximum current for a 12g and 30A is the max for a 10g under normal conditions)

You wouldn't even notice the savings on the average household bill. The reason for the savings is a lower line loss from the wire as you cut the current in half.

FYI-This is one of the reasons power companies transport electricity over large distances at very high voltages and lower currents...they want to deliver maximum power with minimal wire losses.

[John Davidson]

Dick, you are right in the fact that some equipment companies will make claims of higher HP and in the fine print specify Peak HP. As an example, years ago I bought a Craftsman table saw that was marketed as 1.5 HP. In the small print it specified the 1.5 as peak HP. However, when you looked at the nameplate on the motor it clearly stated that the motor was 1hp. In the cases that you refer to it is done for marketing. The industry standard for HP rating on AC induction motors is HP at rated speed. Duty cycle is also listed. High / low current is also listed. But the HP is the same and 1 hp = approx 750 watts. The high low voltage configuration has no effect on the rated HP.

What you show in you savings assumes full load current at all times. However, you will not find that to be the case. When you consider less than FL current the IR losses that you refer to get even much smaller.


As for the torqure differences on you lathes unless you have measured the torque using some device at the output shaft you are making a subjective opinion. Also are the motors rated at the same speed for both lathes. If you are going by what you experience on the spindle are you considering the transmision of power through the mechanical drive system? All these will effect the feel at the spindle.

[Mike Henderson]

While it's true you might save a small amount of money by using 220V instead of 110V because of slightly smaller resistance losses in the feeder circuit, when you decide to use 220V you limit your flexibility to re-arrange your shop. If, at some time in the future, you decide to move the tool you set up for 220V, you may have to run a new 220V circuit to feed it. The cost of doing this will be much greater than the small savings from lower resistance losses.

Think of the number of hours you use your tool, and how often you use it at full load, and you'll appreciate how small the savings are from lower resistance losses.

Any tool that can be run well at 110V is probably best left at 110V.

Mike

[Art kraft]

Dennis
Most all of the responses are correct. HP is power (Watts=Volts X Amps) 750 watts/HP.
One very important thing to keep in mind, when using a VFD (variable frequency drive) most manufactures recommend that you down rate the motor by 10%. This is due to loss of torque at lower speeds and that cooling capability decreases with lower speed.
I have 3ph power in the shop and run 11 vfd powered machines. Torque loss at low speeds in huge, even though manufactures claim otherwise. I use 5hp motors many times where 2 might work just to compensate. You can run a 60 hz motor at 120 without any problem. This doubles speed so you can gear down the motor to spindle ratio, this will help with torque loss. I like 3hp because motor size is smaller and I can pick up surplus motors for as little as $5.00 www.Surplus Center.com. E-bay has a lot of good deals on vfd. I picked up a 20hp for $600. About $3200. new just make sure you get HMI with it.

[Reed Gray]

Well, I am no electrician, but when setting up my shop, I read about voltage on your motors. Basically it was stated that motors in the 1 hp range and bigger ran better on 220, than they did on 110. I had 2 machines rewired to 220, a 2244 Performax sander, and a Powermatic 8 inch jointer. Both ran a LOT better after switching to 220. I think the Jet comes in 110, or 220. The comparable Delta did as well. The manufacturers idea is that more homes will have 110 available, and not many will have a 220 circuit available. The Delta now is 220. Jet should follow suit.
robo hippy

[Mike Henderson]

Well, I am no electrician, but when setting up my shop, I read about voltage on your motors. Basically it was stated that motors in the 1 hp range and bigger ran better on 220, than they did on 110. I had 2 machines rewired to 220, a 2244 Performax sander, and a Powermatic 8 inch jointer. Both ran a LOT better after switching to 220. I think the Jet comes in 110, or 220. The comparable Delta did as well. The manufacturers idea is that more homes will have 110 available, and not many will have a 220 circuit available. The Delta now is 220. Jet should follow suit.
robo hippy
If they ran a lot better when you put in a new 220V circuit, you should probably check your 120V circuits. The wires are probably too small.

Mike

[Dick Strauss]

The other caveat for saving money by using 220V vs 110V is that it is a savings for that circuit only. The tool circuit is probably less than 10% of your overall household usage. If so, your maximum electrical savings is 1% of 10% (or 0.1%). This translates to a likely monthly savings of $0.10 on a $100 electric bill (whoopeee!!!)


Motor HP Differences
With motors you can get two motors that are rated for 1 hp but are very different. Let's say Baldor/Leeson/Marathon are conservative and actually make motors that put out 1.3 hp but call it a 1 hp motor because it is not up to snuff to call it a 1.5 hp motor. Let's say another company makes a motor that produces 0.90 hp but calls it a 1 hp motor because it is closer to 1 hp than to 0.75 hp. Are these motors the same when one has 50% more hp (or torque) while both are labeled 1 hp?

Motor Torque Differences
Beyond fudging the hp specs as mentioned above, the motor specs of say 1 hp only specify the full load torque. Some of the better motors can produce 400% full load torque for pullup and 500% for breakdown torque. This means that better motors can come up to speed faster (or with a heavier load) and are harder to stall (which I like for turning) than the average motor.

The motor specs may look the same but they are definitely not the same in terms of real world performance!!!

[Reed Gray]

Mike,
The 120 volt circuits are 20 amp, and dedicated (only one plug) lines. I don't know the guage of the wires, but they were done by an electrician friend of mine (he owns the business) who is also a woodworker. The problem is not in the wires or the circuits. I generally make sure things are over built, an old habit from 30 years of doing concrete work. Better safe than sorry.
robo hippy

[Robert McGowen]

I think that the mods should transfer this thread to the neanderthal forum. :cool:

[Mike Henderson]

The design of electric motors is pretty exact these days (and has been for a long time). It's very unlikely that any motor manufacturer would build a motor which would produce 1.3HP and sell it as a 1HP. The reasons are that the manufacturer would have put more material into the 1.3HP motor, and the efficiency of the motor would not look as good as one designed (and built) for 1HP. (engineers don't just build a motor and see what its HP is)

Likewise, I really doubt if any manufacturer will have a motor that only produces 0.9HP and label it as 1HP. The liability is just too great.

The differences in motors (a quality motor verses a cheap motor) are more in the bearings, the insulation on the field wires (able to stand higher temps) and perhaps in the cooling capability. A quality motor will last longer.

But if you buy a modern motor rated at 1HP, it will probably test out very close to 1HP.

For regular capacitor start motors, the startup torque is pretty much the same. You can get higher starting torque but you have to go to a different starting technique. For example, a replusion/induction motor has a much higher starting torque than a capacitor start motor. But startup torque means very little in woodworking applications because we start our tools without any load.

Finally, the pullout torque is about the same on all motors designed for the same application. The location and "height" of the torque peak in a motor torque curve is mostly due to the rotor resistance and reactance. But most general purpose motors have very similar torque curves.

But even if there was a major difference in the torque curves of different motors, you should never operate a motor such that it reaches the peak of the torque curve. Even getting close to that point means the motor is well into overload and in danger of overheating.

When you pay more for an electric motor, you are not getting more power than the nameplate power, you're getting a motor that will last longer, and may be more efficient. For industrial motors, the operating cost is many times more than the acquisition cost.

All this assumes you're comparing apples to apples. There are special motors that have special characteristics but if you're comparing motors for the same intended application (which is likely to be true for woodworking tools) they're all pretty close. But the quality motor will last longer and may be more efficient.

Mike

[An added note about getting more than nameplate power out of a motor. Some motors have a specification on them called "Service Factor" which is a number like 1.1 or 1.3. What this means is that you can operate the motor at the rated HP times the service factor and the motor will not increase in temperature more than 10*C (if I remember right). But that extra 10*C cuts the motor life in half (if you ran the motor at that HP for it's life). So there's no free lunch.]

[John Davidson]

Mr. Henderson knows what he talks of!

[Mike Henderson]

Mike,
The 120 volt circuits are 20 amp, and dedicated (only one plug) lines. I don't know the guage of the wires, but they were done by an electrician friend of mine (he owns the business) who is also a woodworker. The problem is not in the wires or the circuits. I generally make sure things are over built, an old habit from 30 years of doing concrete work. Better safe than sorry.
robo hippy
There's really only two alternatives. Either you're imagining that the motors have more power on 220V or you have a problem with your 110V circuits. If you can document better performance on 220V (something measureable and not just your subjective opinion) you need to check your 110V circuits because it's the only thing left. Check you motor cord, also.

I can absolutely assure you that a motor will perform exactly the same on low voltage as on high voltage (for a dual voltage motor) provided it is supplied by a proper circuit.

Mike

[Dick Strauss]

Do you make house calls?;)

[Bill Blasic]

The Nova DVR is advertised as having more HP when wired for 220 vs 110 by the company. Having run mine using both there is absolutely no doubt that this is true. More power with 220!

[John Davidson]

There are some, and I have only seen single phase motors like this, that basicly have a wiring configuration in the high voltage setting that extends the windings on the high voltage arangement. Basicly that taps along different lenghs of the windings to increase the proformance when 220v is used. This type of motor is usually more expensive than the normal high/low induction motor but could be a nice feature. The motor is really designed as the higher HP with taps added along the winding to so that in the reduce hp configuration the current load is still within normal limits for the common home 110v branch curcuit. All the ones that I have seen like this picks up about 1/4 horse when changed from low to high voltage. I know that Delta also had a contractors saw that was like this. However, when a motor company does this they list two HP ratings, one for each voltage configuration on the name plate. If only one HP rating is listed on the name plate then the motor has the same preformance curve in high or low voltage.

One thing that you must remember that there are many types of AC motors and configurations. There are exception to almost every rule but they are few and far between. Mainly because they tend to be more expensive options. For most home shop woodworking machines you will have either an standard single phase AC induction motor or a universal motor.

[Mike Henderson]

The Nova DVR is advertised as having more HP when wired for 220 vs 110 by the company. Having run mine using both there is absolutely no doubt that this is true. More power with 220!
The Nova does indeed have more power at 220V than at 110V. But it does not use an induction motor - it uses a stepping or servo motor (I'm not sure which).

My comments above were specifically about an induction motor. I apologize if I did not make that clear.

Mike

[BTW, the Nova DVR is a very nice lathe. I had the opportunity to use one a while back and was very impressed.]