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cts_casemod · 12-14-2014, 09:12 AM

Time to use some brain cells folks

I'm designing an algorithm for the induction motor.

Ok, everyone knows that above nameplate speed the V/Hz ratio and the torque start to fall, but exactly by how much I cant find.

I thought about using the HP formula HP = (torque(nm)*Speed(RPM))/5252 but assuming the V/Hz ratio goes down, so does the slip induced current on the rotor, so I would have to increase the slip to have a constant secondary output. Problem is such functions are often not linear.

I cant really find any good source that discusses this on the field weakening region. Any ideas?

12-14-2014, 09:12 AM	#1453 (permalink)
cts_casemod EcoModding Apprentice Join Date: Nov 2012 Location: East Midlands Posts: 180 Thanks: 13 Thanked 81 Times in 52 Posts	Time to use some brain cells folks I'm designing an algorithm for the induction motor. Ok, everyone knows that above nameplate speed the V/Hz ratio and the torque start to fall, but exactly by how much I cant find. I thought about using the HP formula HP = (torque(nm)*Speed(RPM))/5252 but assuming the V/Hz ratio goes down, so does the slip induced current on the rotor, so I would have to increase the slip to have a constant secondary output. Problem is such functions are often not linear. I cant really find any good source that discusses this on the field weakening region. Any ideas?