Reduced-order thermal behavior of universal motor-driven domestic food mixers/grinders using AC and DC supplies

Abstract

This paper presents an improvement in the thermal performance of universal motor, which improves the efficiency and increases the life of the motor. Excessive heating in the winding can lead to an insulation failure of a universal motor and reduce the life of a food mixer. Hence, to avoid hot spots in machine parts and obtain a homogenous temperature distribution, it is necessary to take the thermal limits into consideration. To monitor temperature increase, a lumped parameter thermal model is designed with 12 nodes for a food mixer driven by a universal motor. This paper proposes a reduced-order thermal model for a universal motor used in food mixers to monitor its thermal behavior. In this paper, a 12th-order model is reduced to a 5th-order model using a balanced truncation reduction method. The reduced-order model is validated through simulation and experimental results by comparing its response with a full-order model. A thermal analysis is carried out using AC and DC supplies along with experimentation. It can be seen that when the universal motor is operated with a DC supply, its thermal performance is improved, which increases the life of the machine. This results in energy savings, since the efficiency of the universal motor is increased when it is operated using the DC supply.