A new approach to motor condition monitoring in induction motor drives

An approach for condition monitoring of an electrical machine is proposed. The method uses the power leads of the machine itself as the communication link between the sending station located within the machine and the receiving station located remotely outside the machine. The required communication circuit for realizing data transmission for both the ordinary 60-Hz power line and the special PWM (pulse-width-modulated) inverter-fed power line is constructed. The communication circuit uses an asynchronous serial communication protocol and FSK (frequency shift keying) modulation for realizing frequency multiplexing in the power line. An online winding temperature monitoring system for an inverter-fed induction machine is constructed using this power line communication link. Experimental results demonstrate satisfactory operation of the system.<
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