Investigation of unbalance supplying voltage on the thermal behavior

of squirrel cage induction motor using monitoring system

H. Feshki Farahani, H. R. Hafezi, D. Habibinia, A. R. Jalilian and A. Shoulaei

Abstract

The losses in electrical machines causes decreasing of machine lifetime and breaking down of insulation. Therefore, in order to extend the insulation life, it is critical to monitor the stator and rotor temperature and protect the motor under thermal overloading conditions. However, the stator winding and insulation is designed for safety operation but the winding temperature can be risen under special conditions such as motor stall, jam, overload, unbalanceed operation, and situations where the cooling ability of the motor is accidentally reduced. In this study the effect of unbalance supplying voltage on the motor temperature rising has been investigated. For this purpose, by construction of the rotor and stator monitoring system, different unbalancing types have been applied on the 1.1 kW/ 50 Hz/ 1400 rpm motor and by doing different tests such as lock rotor, no-load and etc the effect of any type of unbalancing on the temperature rising has been investigated.