I have a motor that has to be rated for 460V even though the supply voltage is 480V. However the motor will be driven by a vsd which i assume will be rated for the 480V plus or minus variations in voltage and frequency. So let us imagine a 10% variation and 528V is applied to the vsd will the motor be ok?

Thanks
Liam

 

Presuming this is a for a US location.

nominally the motor is rated for 480V, but the usual voltage is closer to 460.

the VFD will supply whatever voltage is required to the motor.

most drives I work with that are nominally 480V would accept +10% so 528V would not trip the drive, but a higher voltage typically would trip it.

--
Bob
http://ilbob.blogspot.com/

 

The short answer is "Probably". Depending on what make of drive and how you set it up at commissioning. There is no physical connection from line side to load side of a drive. The drive takes the line side supply, converts it to DC and then the processor will produce a synthetic sine wave using pulses of DC using IGBTs. So the processor should control voltage and current going to the motor regardless of line voltage. (It will maintain the motor voltage SET by you (460V)) BUT... again, depending on make of drive, you may get line voltage faults, DC Bus voltage faults, some drives could give you current faults based on variations in voltage, it may also give you phase loss faults if voltage dips lower on a phase... These are all parameters that must be set up in the drive at commissioning. The drive will attempt to protect the motor but if your FLA is say 10 Amps and you set the Max Current in the drive to 20 Amps, the drive will not shut down until it exceeds 20 Amps. The same for voltage, the motor is rated for 460V, if the drive's Motor Voltage is set for 480V, it will send 480V to the motor, adjust this from 480V to 460V and then the drive will send 460V to the motor. (It is only as smart as you make it) Most drives are set at the factory to kinda work out of the box based on typical settings, but setting motor speed, voltage, FL and SF Amps, Hz, and fault parameters usually always need to be set up for maximized performance and protection. Also check the maximum voltage rating on the drive, the motor may be ok but a high voltage surge could damage the drive itself. Most drives will shutdown to protect the motor but they can't protect themselves from line voltages high or low.

Hope this helps out.