460 V MOTOR WITH 440 V SUPPLY AND 480 V DRIVE

Status
Not open for further replies.

EdCampbell

Member
Location
Mexico City
Occupation
Maintenance Technician
Hi, I have the following. 1 x 460 v 3 phase motor driving a turbine. 1 x 440 V 3 phase supply. 1 X 480 V YASKAWA F7 Varispeed variable speed drive, and I want to connect the three. Is this possible? The drive characteristics are: Input voltage 380-480 V 50/60 Hz. Output is 0-480 V 0 - 400 Hz.

Thanks in advance. Ed
 
Did you actually measure your incoming voltage, or are you assuming?

"440V" has not been a standard in North America for over 30 years, the standard now is 480V. That doesn't mean legacy systems have upgraded, many have not. But in many cases people call it "440V" still and are unaware that it hasn't really been that for decades.

Anyway, motors are designed for 460V partly for that reason. Motor design specs call for +-10%, utility delivery specs call for +-5%. So you do the math, you'll see that 440-5% is still greater than 460-10%. The motor is fine. The VFD is capable of operating at any voltage in that range, probably +-10% as well, so it's fine too. The thing is though, the VFD cannot create voltage that is not there, so your maximum voltage will be 440V out of the VFD. Read your manual as to what to do about that, the drive mfr may want you to fool the drive into thinking you have a 440V motor so that you can get full output, or it might want you to enter the actual nameplate data and let it take care of the problems that might arise.
 
It is possible and will likely work, but the specifics will depend upon the exact load requirements and motor characteristics. Application engineers are your friends :)

The supply voltage will set the 'DC rail voltage' of the drive, and the DC rail voltage will set the maximum output voltage.

Because your supply voltage is lower than the nominal voltage rating of the motor, it is likely that the drive will not be able to supply the full nominal voltage of the motor (some drives can boost voltage, most cannot). Since your supply voltage is only slightly less than the motor nominal voltage, this is likely not a problem.

Since motors are driven at lower voltage when driven at lower speed, then the motor will likely be driven with 'proper' voltage for most of its operation.

-Jon
 
Did you actually measure your incoming voltage,or are you assuming?
"440V" has not been a standard in North America for over 30 years, the standard now is 480V. That doesn't mean legacy systems have upgraded, many have not. But in many cases people call it "440V" still and are unaware that it hasn't really been that for decades.

Anyway, motors are designed for 460V partly for that reason. Motor design specs call for +-10%, utility delivery specs call for +-5%. So you do the math, you'll see that 440-5% is still greater than 460-10%. The motor is fine. The VFD is capable of operating at any voltage in that range, probably +-10% as well, so it's fine too. The thing is though, the VFD cannot create voltage that is not there, so your maximum voltage will be 440V out of the VFD. Read your manual as to what to do about that, the drive mfr may want you to fool the drive into thinking you have a 440V motor so that you can get full output, or it might want you to enter the actual nameplate data and let it take care of the problems that might arise.

Hi, yes I did check the voltage. Before I continue I am in Mexico. I have an old machine that was made in 2001 and it uses a 440 volt supply for the high power systems - UV lamps etc. I have a step up transformer that is giving me that voltage. I will check on that info. I think maybe it would be a good idea to contact the drive agency here in Mexico and see what they say. If it will not work I will just have to stick to 220V and run like that.
 
Status
Not open for further replies.
Top