Industrial Engineer · phase 10 of 16
Slip
Difference between an induction motor's synchronous speed and actual rotor speed.
The Explain card
- Plain English
- Slip is the difference between synchronous speed and the speed the rotor actually turns. An induction motor needs some slip, because the rotor only makes torque when the field is moving past it.
- Example
- A motor with a synchronous speed of 1800 rpm turns 1760 unloaded and 1740 at full load. That 60 rpm at full load is about three percent slip.
- Why it matters
- Slip grows with load, so shaft speed drifts down as the machine works harder unless the drive compensates. A motor with far too much slip is overloaded, under voltaged or has a rotor problem, and slip is how you tell.
- Hook
- The rotor is always chasing the field and never catching it.
Where it sits in the deck
Phase 10: VFD Electrical and Motor Fundamentals
The physics under the parameters: slip, torque, flux, and the relationship between frequency and voltage that every drive is really controlling.
