The power losses calculation technique of electrical machines using the heat transfer theory

The paper proposes the estimation of power losses in electrical machines using a measurement technique based upon electrical machines ventilation wind temperature and a heat transfer equation. Three machine types are tested under various load conditions using the proposed technique. The first machine type are a three-phase 2.24 kW and a 3.73 kW induction motors. The second is a 4.5 kW synchronous generator. The last is a 5 kW dc machine which is operated as both motor and generator. The results show that the machine power losses calculated from the proposed technique has an error less than 4 % comparing with power losses from the experiment. Therefore, the technique can be acceptable for the estimation of power losses in electrical machine. The main advantage of this method is that the machines need not to stop or to be removed from their operation process in order to measure their losses.