Derivation of induced motor models from standstill frequency response tests

Standstill frequency response (SSFR) tests were conducted on four induction motors with ratings of 300, 400, 1000, and 1750 horsepower. Using the SSFR test data, an equivalent circuit was derived for each motor. The speed-torque and speed-current curves calculated from the equivalent circuit were compared with those reported by the manufacturer. The comparison showed good agreement of the SSFR-based model with manufacturer's performance curves in the case of the 300 hp motor. Including a simple approximation for saturation effects provided reasonable agreement for the 1000 hp and 1750 hp motors. Results for the 400 hp motor were at considerable variance with manufacturer's curves.>