Energy balance and heating curves of electric motors based on Infrared Thermography

In the present study, a methodology has been designed in order to establish an energy balance of an induction motor, through the use of Infrared Thermography. Tests were performed on a 1.1 kW induction motor operating at full load. Thermographic images of the chassis temperature were captured at every second from the starting up of the motor till the switch off and final cool down, by using an infrared camera connected to a laptop computer with an acquisition and analysis program installed. Initially, heat losses by convection and radiation from the surface of the machine were calculated using its geometrical dimensions and temperature values obtained from the thermographic images. Any motor configuration and working conditions can be accurately studied using this procedure by just varying the m·Ce, NTU, μ and/or fan diameter. Additionally, the developed model proves that infrared thermography can be considered as a valuable tool to perform energy balances and to obtain the heating curves of the machine with enough accuracy.