Thin film sensors for flux and loss measurements

Sensors comprising a thin film structure have been deposited on the surface of several laminations by vacuum evaporation of metals. Thin film sensors are robust, easy to use for laboratory and industrial experiments, versatile and above all far more accurate and reliable than traditional devices. The transformer and rotary machine manufacturers are willing to use thin film sensors in their devices for continuous monitoring of the condition of their machines while under regular operation. Thin film sensors are useful to measure iron loss in motor assembly and in use; principally to improve motor design understanding thereby achieving improved efficiency in practice. In addition an insight to part of stray loss whose component comes from high frequency iron loss is recognised as changing with time due to changing interbar conditions. Both these effects (lamination stresses and high frequency losses) are important for both stators and rotors and are influenced with skew and time in service. This technique is extremely useful if the sensor is to be used inside an electrical machine, where it must be allowed to move in the air gap and is a risk of damaging other areas of the machine