A new radio disturbance measuring apparatus for asynchronous slip-ring machines

IEC 60034-1 Ed 10.2 1999-08 -states in Section 12-Electromagnetic Compatibility (EMC) the limits for the conducted disturbance on AC supply terminals of asynchronous machines with slip-rings. CISPR standards describe the radio disturbance apparatus and methods for measurement of conducted disturbances, but this equipment seems not to be suitable for electrical machines with slip-rings in which the disturbances are originated by sparks in brush-ring contact. Our studies on spark-produced disturbances have led to the development of a continuous monitoring of sparking level device. From this device we have a new radio disturbance measuring apparatus, containing 5 modules: close magnetic field probe, conversion block, totalization and recording block, data management and final storage, data display. Extensive tests have been carried out with this device and a good agreement between the observed sparking level and the apparatus indication has been confirmed.