Battery free condition monitoring

“The microgenerator and supercapacitor combination eliminates battery reliability issues and time consuming maintenance, whilst enabling significant savings in operational costs and energy use,” said Dr Stephen Roberts, technical manager for Perpetuum. The PMG17 microgenerator converts mechanical vibration into useable electrical energy. After being stored in a CAP-XX supercapacitor, this energy can power wireless sensor nodes indefinitely, say the companies. The supercapacitor stores the energy harvested by the PMG17, then delivers the peak power needed to transmit sensor condition data over wireless networks such as IEEE802.15.4 (Zigbee) and 802.11 (WLAN). The microgenerator’s output is said to be high enough to meet the power needs of intermittent radio sensor systems, such as Wireless HART, SP-100 and Wi-Fi in industrial applications, but its output impedance is said to be too high to supply the power required by sensor nodes during data collection and transmission. However, the high capacitance and low equivalent series resistance of the supercapacitor allows peak power to be generated for approximately one second – long enough for data to be transmitted. In a field trial at Shell’s Nyhamna gas plant in Norway, the PMG17 and CAP-XX supercapacitor system was used to power wireless sensor nodes. Operating in a wide range of temperatures, the sensors monitored the condition of rotating equipment, reporting temperature and overall vibration every five minutes. For more on the trial: http://www.cairnstone.co.uk/PDF%20Files/Norwegian_Technology_01.pdf