575 or 220 volt motors

What happens if you try and run a 220 volt motor with 575 volts?
And vice -versa? Can you run a 575 volt motor on 220 volts?
This would just be in a testing situation, not as a permanent setup.

There are some built in motors on my new cinnci mill and I think they are 220 volt but someone has marked them as 600 volt. The main motor for the horizontal spindle is clearly marked as 220 volt and runs just fine. The powered overarm motor has been over-stamped as 600 (220/440 underneath) but it runs fine on 220 volts.
The power feed motor on the knee appears to be 220 volt but someone has marked it in felt pen as 600, same thing for the coolant pump. My guess is that they are all 220/440 and some idiot got in there with a felt pen and a stamp. Not to mention the tag inside the electrical switch noting the incoming 600 and 220 volt wire sizes.

I would assume all motors to be the same voltage on a machine that looks to be in original condition and I just wanted to know if there is a downside to testing the motors with the different voltages.

Pics of the mill on the heavy iron forum

Thanks
Michael

can you run a 575 volt induction motor on 240 vac? yeah, it should spin up. it might have 1/9th as much torque.

to try and run an induction motor on 3 times its design voltage.. i'm guessing it will burn out in 20-40 seconds.. flames escaping from burning polyamide in 40 seconds max..

The rule of thumb is plus or minus 10% for voltage for motors. After that, the outcome is not too good. Bob

Motor Voltage Clues

M. Moore said:

My guess is that they are all 220/440 and some idiot got in there with a felt pen and a stamp. Not to mention the tag inside the electrical switch noting the incoming 600 and 220 volt wire sizes.

I would assume all motors to be the same voltage on a machine that looks to be in original condition and I just wanted to know if there is a downside to testing the motors with the different voltages.
Michael

Click to expand...

Sounds to me like you have a hybrid machine, built for the US market (220/440), but modified with CA (600) spare parts or rewound motors.

First thing to check is the number of leads on each motor. Standard dual voltage motors have 9 leads. Single voltage motors usually only 3 leads. If the ones labeled 600 are 3 lead only, you better believe it. If there's 9 leads it's a dual voltage. If a good motor shop rewinds a stator for a different voltage than it comes in with they stamp mark it over the original on the factory tag. A one man shop may just be using a marker or label printer.

It's no problem running them at the lower voltage for testing, but they will not develop full power that way (V/Hz ratio).
Higher voltage on the windings, than rated, may pierce the winding insulation, especially if they are old or contaminated. If they are 3 lead and marked 600 I would bet they have been rewound or replaced.

Check that tag inside the panel, does the amperage (wire size) markings at each voltage correspond to the ratings that the motor loads are marked, as to the current required ? Is there 2 sets of 3 phase wiring in the control panel, one for each voltage, to different starters? If so, this would confirm a hybrid.

I use a autotransformer setup to bench test motors and equipment. It outputs 120, 208, 230, and 460 3Φ. Motors tested across the line, on the floor, are started at 120V 3Φ and ramped up to their rated running voltage, to prevent them from rolling or jumping off the floor. No harm done for testing at lower than rated voltage. Higher voltage would probably be OK for a healthy winding and a short test. Not really sure what that would prove though, unloaded they would likely run fine on either voltage.
Ω

Thanks all for the prompt info.
saf, the wire info is exactly what I need to confirm the voltages of the motors.
I did test the two motors with 220 volts and they both run, I did not load them so no info on torque.

The number of wires will tel the true story on these, I have a hard time imagining them being rewound, given the cost, changing the switch gear etc etc.

I will be getting at this soon and will post the info.

Thanks,

Michael

Might there be a transformer buried in the system somewhere?

Saf,
Thanks again for your info.
I finally had time to dig into the two motors that are suspected of being the higher voltage.
They both have only three wires coming off the winding, so it does look like 600 volt for those motors.
I did not have time to run a test wire to the machine at the higher voltage but I will get to that soon so I can test them out. Well I will only test one as the coolant pump motor needs a new lower bearing as it was seized.
The knee motor is the important one anyway, it did run on the 220 volt test but did not power up the any of the table feeds.
Perhaps it will work better at the higher voltage but I can't figure out why it would, but then again I am not that smart.
I will post up some pics if I get a chance.

Michael

A 220 motor runs fine on 600 (assuming the insulation can take it)...................bnut there is a detail.......

The detail is that you also need to use a VFD and run the motor at 180Hz.....and it will also produce 3x the power..... It's all about the V/Hz ratio..... keep that constant, and all you need to worry about is insulation, and possible "birdcaging" (centrifugal force related failure) of the rotor....

Just an update for all the helpful responders.
I finally managed to get some time and wire up temp power to the machine with dual voltage.
The feed motor runs just fine on the 575 volts and once I got the rotational direction correct the feeds and speeds and rapids were working fine, what a relief!
So now I just have to move the mill inside and get it installed in its new place in the shop, oh- and make some chips!

Thanks all,
Michael

thermite said:

So all those major motor makers with different voltage options on their order lists, or 220/230 <=> 440/460 V and similar re-connect diagrams on their motor data plates

...are just wasting their time to wind different wire sizes and turn-counts?

Click to expand...

it might be cheaper to wind a motor with fine wire, i don't know. i do know almost all small motors have all the coils pressed into the winding at the same time.
like this: https://www.youtube.com/watch?v=RTJuj2mg57A


most motors i've unwound, they wind both coils together. so when you connect them for 440vac, you have at least 240vac between every single wire. rather than separate isolated coils which would only see .5 to 2 volts per turn of wire.
you will probably find a higher reliability with motors connected for the lowest voltage possible. but all coils are used equally, it is the same copper loss regardless how they are connected, if its wired correctly.

I used to work in Marathon Electrics winding department. We had three sizes of wire to wind motors from 20 hp to 1250 hp, 360 frame to 5000 frame. All low voltage motors (under 600 volts) were wound with this wire. We made motors for europe over 500 volts, and down to 220 commonly-however the design was changed by turn count for the amperage. I was amazed at the lack of change for all the variances in voltage. Rotors were all identical.
Joe