Useful life – Determining factors

In electric motors, several factors combined with each other and with the temperature are important factors and determinants of the life of the machine, and they are the high variation of the winding temperature and during normal working conditions, such as being part of the day the motor is switched on and the other part is switched off, the frequency of the start-up, because during the start, especially the direct in the network, a great mechanical effort occurs in the coils caused by the high current circulating in the copper. This effort tends to bend the coil head towards the rotor causing microcracks in the insulation.

In the motors, the drive by frequency inverter provides them with high frequency voltage waves and with a high speed of voltage variation and the higher the dV / dT the higher the insulation request, also the ambient conditions of the installation site , because aggressive environments act directly on the insulation material of the coils and the level of vibration of the motor, are conditions of general maintenance in the electric motor and we must verify the other exceptional conditions of operation, that affect the duration and the useful life.