When to use this calculator
Compare rotor speed with a synchronous reference speed. Negative slip can occur in generating operation; the tool does not infer the operating mode.
Explore the ac power & reactance calculators for other questions in this topic. For a related calculation, use the Inductive Reactance Calculator: Find ideal inductor reactance magnitude for sinusoidal AC.
PUTTING IT INTO PRACTICE
Induction Motor Slip: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Synchronous speed (rpm) | 1,500 |
| Rotor speed (rpm) | 1,440 |
| Result | 4 % |
- Check the input labels and enter the example values above.
- Apply the relationship: Slip (%) = (synchronous speed − rotor speed)/synchronous speed × 100.
- The result is 4 %, rounded for display.
How to interpret your result
Negative slip can occur in generating operation; the tool does not infer the operating mode.
Use RMS values in the AC power relationships. Apparent power is measured in VA and real power in watts. Pure-sine conversions and balanced three-phase equations only apply under their stated assumptions.
Frequently asked questions
Why can volt-amps differ from watts?
Apparent power is the RMS voltage-current product, while real power also reflects power factor. They are numerically equal only at a power factor of one.
When is the induction motor slip calculator useful?
Compare rotor speed with a synchronous reference speed. Negative slip can occur in generating operation; the tool does not infer the operating mode.
How do I use the induction motor slip calculator?
Enter synchronous speed (rpm), rotor speed (rpm). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Slip (%) = (synchronous speed − rotor speed)/synchronous speed × 100.
What should I check before using the result?
Negative slip can occur in generating operation; the tool does not infer the operating mode.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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