Low cost wireless sensor network for in-field operation monitoring of induction motors

In most modern industries there is a growing need for high efficiency and availability in motor driver systems. Moreover, motor operation monitoring is necessary to the implementation of proper and cost-effective motor maintenance, repair and replacing strategies. In this paper, a wireless sensor network for in-field operation monitoring of three-phase squirrel-cage induction motors is proposed. The network is able to sink operation-related data of several motors to one central point. A number of hardware platforms for wireless sensor networks where evaluated and a low-cost platform was chosen to implement a simple operative communication protocol. The protocol is used to improve deployment and commissioning of the wireless network which are time and manpower consuming tasks and, therefore, has to be regarded as one of the main cost factors when using and implementing one such network. Furthermore in industrial environment node placement is not random because each node has to perform a specific task (e.g., monitoring a specific machine). All operational data is provided by a device that is able to read line currents, line-to-line voltages and temperatures, and performs several calculations such as power consumption, power factor, load factor, voltage and current unbalance. This device is also able to automatically manage the stator winding connection mode as a function of the linear current, in order to improve motor efficiency and power factor.