OPTIPACT sensors from INTACTON for velocity measurement in wind turbines are a non-contact, maintenance-free alternative to rotary encoders and proximity switches. These solutions, which have been used primarily until now, have proven susceptible to errors and to require high maintenance – moreover, their mechanical integration is very complex. Since the easy-to-install, cost-efficient OPTIPACT systems drastically decrease installation and maintenance efforts, even the redundant installation of two units is economically sound. The signals are ideally suited for speed control and improve efficiency over conventional systems in most cases.
OPTIPACT sensors analyze moving surfaces and feed the control system with the resultant data. Their operating principle is based on the correlation method which enables detection and tracing of characteristic structures within the field of view. In wind turbines, OPTIPACT sensors are installed in a stationary posi-tion with the integrated 2D camera focusing any moving surface. The signal generated from the measured data corresponds to that of an incremental en-coder. By means of a reference mark on the hub, OPTIPACT can monitor not only the revolutions per minute but also the rotary position of the hub – this additional information can be used for monitoring the revolutions and to position the rotor.
OPTIPACT sensors consist of an LED illumination unit, a 2D camera, transmit-ting and receiving optics, and integrated analysis and interface electronics. Measuring 98 x 42 x 47 mm and weighing merely 250 grams, the units can be easily integrated into almost any application. The sensors are housed in an IP65-protected aluminum enclosure. An incremental interface and an RS232 interface are available for communication with higher-level PLCs. INTACTON implements fieldbus systems or an SSI interface on request.