I'm trying to work out stator input power of a 3 phase delta connected induction motor.

I have the equation Stator Input Power (P1),

where P1= Pm + rotor copper loss + rotor stator loss.

I have Pm and rotor copper loss but don't know how to find the equation for rotor-stator loss. If anyone could help out that would be greatly appreciated.

  • \$\begingroup\$ The "electrical" and "engineering" tags are pretty much useless. If you want people who are interested in induction motors to notice your question, use the "induction-motor" tag. \$\endgroup\$ – Charles Cowie Jun 4 '19 at 2:01
  • \$\begingroup\$ Thanks very much for the tip! \$\endgroup\$ – Sophie Jun 4 '19 at 14:50

For an induction motor, the motor input power is equal to the mechanical power developed in the rotor plus the stator copper loss plus the rotor copper loss plus the iron loss.

The rotor copper loss is the mechanical power developed in the rotor multiplied by per-unit slip. Per-unit slip is (synchronous speed minus rotor speed) divided by synchronous speed.

| improve this answer | |
  • \$\begingroup\$ I don't have iron loss given in my equation I have rotor copper loss and Pm. My equation is for Output power with friction losses. Where Pm= 2 x pi x nr and then did Pm-mechanical losses. \$\endgroup\$ – Sophie Jun 4 '19 at 14:48
  • \$\begingroup\$ For rotor copper loss I first worked out Ir, then loss per phase and finally total copper loss. \$\endgroup\$ – Sophie Jun 4 '19 at 14:49
  • \$\begingroup\$ How would I work out rotor stator loss? \$\endgroup\$ – Sophie Jun 4 '19 at 14:50
  • \$\begingroup\$ I have never seen the term "rotor stator loss." The only losses in my books are the ones I listed plus mechanical losses and "stray losses." Stray losses are essentially losses that can not be determined. \$\endgroup\$ – Charles Cowie Jun 5 '19 at 3:04
  • \$\begingroup\$ How would you then work out input power then because I'm trying to work out input and output power so I can calculate the mechanical efficiency of my motor at full load running speed? would input power be mechanical power + mechanical losses. Mechanical losses was the only value I was given. \$\endgroup\$ – Sophie Jun 5 '19 at 17:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.