a question about 460V/60Hz motor run on 380V/50Hz power supply
a question about 460V/60Hz motor run on 380V/50Hz power supply
(OP)
we have a ABB AC 460V/60Hz motor run on 380V/50Hz power supply in China. The motor is connected to a ABB drive. The nameplate of motor rating is 522KW/769Amps/1790RPM/460V/60Hz. Because the V/Hz is almost the same between 460/60 and 380/50, i think the torque and FLA should be about the same between these two. My question is that which values should we enter in the VFD for motor rated power, amps, RPM, and voltage, should we enter 522KW/769Amps/1790RPM/460V/60Hz or 435KW/769Amps,1490/380/50Hz? Or they are pretty much the same?
Thanks a lot for your help.
Thanks a lot for your help.





RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Muthu
www.edison.co.in
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
do we need to derate the current? Both power and voltage is derated at 5/6, so current will be about the same?
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Your VFD will report undervoltage fault when its DC link voltage falls below 65 to 51% of the nominal level. Your dc max at 480VAC will be 1.414 x 480 = 679VDC. Your fault trip would then be around 441VDC (311VAC).
Your VFD load settings will have to be conforming to the specs of the driven motor though. If your supply is 380V, try and see if your unit can be set for that system voltage.
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
The output frequency of VFD is 50Hz if I understand correctly. We will lose some speed, but 1490 is more than enough for our application (torque is more critical). How about the full load amps at 380V/50Hz? Should it be ~769amps or we also need to derate the amps at ratio 5/6?
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Sorry that i don't fully understand your calculation (chemical engineer myself). but it seems that you think we should put in original machine specs at 480V/60Hz in our VFD load setting, correct?
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Muthu
www.edison.co.in
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
You do not de-rate the current.
You could use the 60Hz numbers but that is more likely to leas to a parameter setting mistake that causes an odd knee frequency so it produce the correct V/Hz ratio. 50Hz parameters and 50Hz as the maximum frequency are easier to set.
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
The VFD will switch on, but the motor and VFD combination won't operate correctly at such a low input voltage. I think you're answering a different question to the one the OP asked.
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
As I said, your motor will be perfectly happy receiving 380V 50Hz. You WILL get full rated torque from it, just not full 60Hz speed at full rated torque. With it being a VFD, you COULD make the output be 60Hz, but still at 380V max, so it is only when you go ABOVE 50Hz output that you begin to lose torque. Since you indicated that torque is more important than speed in your application, you can run at 50Hz and have no issues.
"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
By experience, a VFD designed for "480V" can run successfully when brought to any place where the power supply is 400V. It's of the same VFD class-->400V class, to cater for 380-480V systems! The equipment the VFD is driving will run successfully provided the current rating of the VFD is not exceeded. Like I said, the VFD will report an "Undervoltage" fault only if its DC link voltage drops below 65% of its nominal design DC voltage.
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
Motor performance should be equal at either 460 Volts/60 Hz and 380 Volts/50 Hz, up to 50 Hz. Above 50 Hz the torque will start to fall off.
Maximum torque is developed at around 30% to 60% of rated speed.
As an example, if the maximum torque is developed at 40% of rated speed, then an output of about 40% frequency and 40% voltage will develop maximum torque at standstill. (Torque boost for starting problem loads.)
De-rate the motor to 50 Hz and set the VFD parameters according to the de-rated motor values.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: a question about 460V/60Hz motor run on 380V/50Hz power supply
YES!