How to calculate the slip in an three phase induction motor

Click For Summary
SUMMARY

The calculation of rotor slip in a three-phase induction motor can be directly derived using the formula: slip = 1 - pp * RPM / (60 * f), where pp represents the number of pole pairs, RPM is the rotor speed, and f is the input frequency. Knowledge of the output torque and rotor RPM is essential for this calculation, especially when the motor is supplied by an inverter with variable voltage and frequency. Understanding the equivalent circuit parameters (Rs, Rr, Ls, Lm, and Lr) further aids in optimizing motor performance.

PREREQUISITES
  • Understanding of three-phase induction motor principles
  • Knowledge of electrical circuit parameters (Rs, Rr, Ls, Lm, Lr)
  • Familiarity with inverter operation and control
  • Basic grasp of torque and RPM relationships in motors
NEXT STEPS
  • Research the impact of variable frequency drives (VFDs) on induction motor performance
  • Learn about calculating torque in three-phase induction motors
  • Explore advanced motor control techniques using MATLAB/Simulink
  • Study the effects of rotor resistance on slip and efficiency
USEFUL FOR

Electrical engineers, motor control specialists, and anyone involved in the design and optimization of three-phase induction motors will benefit from this discussion.

Jander
Messages
2
Reaction score
0
Hello!
I wanted to know if it is possible to calculate the rotor slip if I know the output torque and rpm shaft. I also know the equivalent cicuit of the motor: Rs, Rr, Ls, Lm and Lr.

Thank you!
 
Engineering news on Phys.org


Jander said:
Hello!
I wanted to know if it is possible to calculate the rotor slip if I know the output torque and rpm shaft. I also know the equivalent cicuit of the motor: Rs, Rr, Ls, Lm and Lr.

Thank you!

If you know the input frequency (this is the mains frequency if it's not inverter driven) and the rotor RPM then that's all you need to calculate the slip directly from it's definition (as opposed to calculating it from the machine model).

slip = 1 - pp * RPM / (60 * f)

Where pp is the number of pole pairs
 
The point is that the motor is supplied by a inverter with variable voltage and frequency, so I wanted to know the slip to calculate the frequency and the voltage to supply to the motor to obtain the desired torque/rpm.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
Replies
9
Views
2K
  • · Replies 22 ·
Replies
22
Views
5K
Replies
2
Views
4K
Replies
4
Views
3K
  • · Replies 27 ·
Replies
27
Views
795
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
4
Views
3K