Feasibility of wireless RF communication inside rotating electrical machines for condition monitoring applications

The present condition monitoring of rotating electric machines are predominantly based on electrical signals available from the stator terminal leads and other physical quantities from external of the machine, while signals internal to the machine remain relatively unexplored. For the ease of deployment of sensing system inside an electrical machine with minimum overall design modification, wireless sensor nodes would be an ideal choice, especially while probing signals on the rotor. In this paper, we investigate and evaluate the feasibility of applying IEEE 802.15.4 based wireless radio within an electrical machine. Based on the experiments carried out using an electromagnet and an induction machine, it was found that contrary to the common belief, the wireless link quality was observed to be improved and not degraded due to the environmental conditions inside an electrical machine. This opens up an opportunity to explore invasive condition monitoring systems for electrical machines.