460v feeding a 230v motor with VFD

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Rhostettler

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Location
Ohio
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Maintenence
We have a dual voltage WEG motor(230v/460v) powering a machine. It has a VFD running it. It is a 9lead 6 peg motor. It is wired for 460v wye from factory.

Is it possible to wire the motor to delta and run it?
 

__dan

Senior Member
It's not clear what you are asking.

Is the motor already running or is it a new installation?

The motor may be dual voltage but the drive may not be. It would go back to the factory ratings of the drive and what you are trying to do with it. You may have to match the drive with the supplied system voltage. That may not be programmably adjustable (refer to the drive manufacturer). Check with the drive manufacturer if your drive matches what you want to do with it, regarding the system supply and load side voltages, and if so any kW derating that may apply. If the drive is adjustable for the lower voltage, it is not going to be rated for double the current at the output.

What is the system voltage, what is supplied to the drive.

The European motor connected 460 Y, if you reconnect it for 230, it will probably be Y again. Why do you want to connect the motor delta. You would have to follow the nameplate connection diagram.

Other than saying call the drive manufacturer for your application, there's no information conveyed in your post.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
I agree with __dan; you need to provide information as to _why_ you would want to do this.

One possible reason is if you want to operate a motor at greater than rated base speed. Common NEMA induction motors rated for 60Hz 'base speed' are often rated for operation at higher frequency; contact the manufacturer for details. If you wish to operate the motor at full V/Hz, then you need to operate at higher than base voltage. So you would use a 230/460 dual voltage motor, wired in the 230V configuration but connected to a 480V VFD.

By its nature, a VFD must be able to produce a lower voltage than its input. So a 480V VFD can be set to a V/Hz ratio to properly operate a 230V motor. But remember that a VFD has limited output current, and if you reconnect the motor for lower voltage, the motor will require higher current to operate. So if you determine that the motor can safely be used at higher than base frequency, and you choose to use the low voltage configuration, then you will need to increase the rating of the VFD to carry the current required by the motor.

In my lab we use this exact setup on a piece of test equipment. We have a dual voltage motor with a nominal 75 Hp rating at 60 Hz. The motor may safely be used at 90Hz. The unit is connected in the low voltage configuration, supplied by a 480V VFD with a 125kW rating.

-Jon
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
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retired electrician
We have a dual voltage WEG motor(230v/460v) powering a machine. It has a VFD running it. It is a 9lead 6 peg motor. It is wired for 460v wye from factory.

Is it possible to wire the motor to delta and run it?
You cannot change a 9 lead motor from wye to delta. You can only change the voltage by connecting the coils in series for the higher voltage and in parallel for the lower voltage. For a nine lead motor the internal connections of 10, 11 and 12 determine if the motor is wye or delta.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
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Electrical Engineer
I agree with __dan; you need to provide information as to _why_ you would want to do this.

One possible reason is if you want to operate a motor at greater than rated base speed. Common NEMA induction motors rated for 60Hz 'base speed' are often rated for operation at higher frequency; contact the manufacturer for details. If you wish to operate the motor at full V/Hz, then you need to operate at higher than base voltage. So you would use a 230/460 dual voltage motor, wired in the 230V configuration but connected to a 480V VFD.

By its nature, a VFD must be able to produce a lower voltage than its input. So a 480V VFD can be set to a V/Hz ratio to properly operate a 230V motor. But remember that a VFD has limited output current, and if you reconnect the motor for lower voltage, the motor will require higher current to operate. So if you determine that the motor can safely be used at higher than base frequency, and you choose to use the low voltage configuration, then you will need to increase the rating of the VFD to carry the current required by the motor.

In my lab we use this exact setup on a piece of test equipment. We have a dual voltage motor with a nominal 75 Hp rating at 60 Hz. The motor may safely be used at 90Hz. The unit is connected in the low voltage configuration, supplied by a 480V VFD with a 125kW rating.

-Jon
Just a word to the wise on doing this. Unless it is stated on the nameplate, ALWAYS get the maximum speed the motor can SAFELY operate confirmed IN WRITING from the motor mfr. Assume nothing, and don't believe the salesmen.
 

paulengr

Senior Member
Just a word to the wise on doing this. Unless it is stated on the nameplate, ALWAYS get the maximum speed the motor can SAFELY operate confirmed IN WRITING from the motor mfr. Assume nothing, and don't believe the salesmen.

NEMA has a chart when the motif states it is NEMA rated giving maximum safe speeds that are minimums. The motor may exceed this but it’s a safe (rated) maximum. For instance most four pole motors can go safely to 2500 RPM.
 

Rhostettler

Member
Location
Ohio
Occupation
Maintenence
Sorry for the late response everyone.

The only reason I inquired is because I had to troubleshoot an issue with a drive not running a machine that had an external communication board attached to a H.I.M. for display purposes. The engineer tried to tell me ;after someone replaced the motor; to wire the motor in a delta config. Not sure why he said that, but ok. He's the engineer. It was a dual voltage motor.(230/460v) i believe he was trying to tell me to wire to 230v to run. Yet as you explained the drive would have to be rated for the amperage. He said it would be fine.(if I had listened to him I would have damaged something else) so I Wasnt getting a bigger drive it worked before. I wired said motor to 460v and left the "wheel" as it was prior. So after replacing the drive for a second time and the H.I.M. it was able to run.

Hope this wasn't confusing. Its been a long night.
 

__dan

Senior Member
If the drive is too small, it might give a torque overload or high current trip. If the load never exceeded the output current rating for the drive, it might run. It's possible the drive would only complain and trip for high current, only if the load exceeeded the drive rating, but I would ask the manufacturer that, or if that's what your engineer wanted. Just make sure the motor nameplate data is correct in the drive.
 

kwired

Electron manager
Location
NE Nebraska
If the drive is too small, it might give a torque overload or high current trip. If the load never exceeded the output current rating for the drive, it might run. It's possible the drive would only complain and trip for high current, only if the load exceeeded the drive rating, but I would ask the manufacturer that, or if that's what your engineer wanted. Just make sure the motor nameplate data is correct in the drive.
I agree. You may get away with it on fractional and maybe up to about 3HP, if motor isn't too loaded. Much bigger than that even no load currents are likely significant enough difference between high and low volts on a dual volt motor it just won't work without bringing up fault codes.
 

jim dungar

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Location
Wisconsin
Occupation
PE (Retired) - Power Systems
We have a dual voltage WEG motor(230v/460v) powering a machine. It has a VFD running it. It is a 9lead 6 peg motor. It is wired for 460v wye from factory.

Is it possible to wire the motor to delta and run it?
The internal winding configuration of a motor is independent of the system configuration. A wye connected motor runs just fine when fed from a delta configured source. What is important is to connect the motor to the proper voltage per its wiring diagram.

The input side of the VFD must be compatible with the source configuration, but again it does not need to match it.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Sorry for the late response everyone.

...The engineer tried to tell me ;after someone replaced the motor; to wire the motor in a delta config. Not sure why he said that, but ok. He's the engineer. It was a dual voltage motor.(230/460v) i believe he was trying to tell me to wire to 230v to run. ...
He was wrong, and you were wise not to follow his instructions. NEMA motors are wound delta or wye based on factors having to do with the manufacturing of it, they cannot be changed or selected in the field. IEC dual voltage motors ARE wound delta/wye to change the voltage; delta is the lower voltage, wye is the higher voltage, but the voltage difference is not 2 to 1, it's 1.732 to 1, as in 220/380V or 230/400V. But that is NOT the case with NEMA motors. 9 lead dual voltage 230/460V NEMA motors are either wye-vs wye-wye or delta vs delta-delta, meaning they remain wye or delta wound regardless of the voltage, you just connect the windings in series for the higher voltage or parallel for the lower voltage. You couldn't have changed it from wye to delta in the field anyway.
 
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