Estimation efficiency of rewound induction motors in situ using a numerical model

This paper presents an effective technique for determining the impact
of rewinding practices on the motor efficiency and characterizing
the efficiency reduction when electrical motors are rewound several times.
This technique focuses on a new approach and a statistical study to find
a numerical model for the estimation efficiency of rewound induction motors
in the field. The experimental results from 101 induction motor tests are
analyzed. A numerical model is determined and compared with different
methods: separate losses method, modified current method and simple
current method. An error analysis is conducted to examine the level
of uncertainty by testing three asynchronous motors at 110 kW, 160 kW, and
300 kW. The results show that this approach can predict and estimate
the efficiency reduction in rewound motors without expensive tests and can
help the energy manager make effective cost decisions in replacing
the rewound motors with more efficient ones by using an assessment
of overconsumption and maintenance costs. Another advantage of this model
is that it can be used to improve the software tools and can also be a very
strong indicator to audit the repair quality.