Magnelab bring their innovative 24 inch flexible Rogowski rope CT coil (RCT) with a range of current ratings up to 5000A. The Rogowski coil is a transducer used for measurement of the high frequency current pulses generated by partial discharge activity in the stator insulation structure. The design and termination of the Rogowski coil are such that it acts as a current transformer at high frequencies but has very low sensitivity to power frequency current. The high frequency current pulses are significantly attenuated whilst travelling through the stator winding and associated cable system. It is therefore desirable that the Rogowski coil be located as near as possible to the source of the discharges, i.e. as near as possible to the H.V. terminal of the phase winding. The coil opens at the connector junction and can be installed on an existing cable or buss-bar in a matter of seconds.
The low-level signals, which are output from the Rogowski coil, are routed to a high-gain integrator amplifier which has an appropriate frequency characteristic to accept the discharge pulse spectrum but rejects the power frequency and the harmonics associated with the machine operation. The discharge signal pattern can then be captured on a digital recorder, together with the power frequency phase voltage waveform. Subsequent computer assisted analysis can be carried out using software specially designed for this purpose. A permanent record can be stored to assist future trending analysis.
Rated input from 500A to 5000A
Phase angle <0.5 degrees measured at 50% rated current
Output of 0.333V AC at rated current
4ft. Insulated leads
Accuracy at 10% to 300% of rated current
Custom output and other parameters are available
Integrator requires 12 to 30V AC or DC power supply