Embedded System for Monitoring Physical Variables of the Electric Machine Rotor
wireless communication, ultracapacitors, energy harvesting, electrical machines maintenance, microcontroller, rotor temperature.
With the wide use of electric machines in the oil industry, particularly in oil lifting methods, there is a growing need to extract information from the machines to optimize their maintenance. The present work shows the development of an embedded system to perform the monitoring of an squirrel cage induction motor rotor physical variables, providing further data for the machine maintenance diagnosis. The system comprises: circuit to acquire desirable rotor variable(s) value(s) and send it to the computer; a rectifier and power storege circuit that besides converting an alternating current in continuous also store energy for a certain amount of time to wait the motor engine shutdown; and magnetic generator that harvest energy from rotating field to power the circuits mentioned above. The embedded system is set on the rotor, making it difficult to power the system because it is rotating, problem solved with the construction of the magnetic generator eliminating the need of using batteries or collector rings and by using a wireless NRF24L01 module to send data to the computer. For the proposed system validation a temperature sensor (DS18b20) was applied, variable known as the most important when identifying the need for maintenance. Tests were made getting satisfactory results proving the viability of using sensors on the rotor.