The IDAX series are diagnostic insulation analyzers based on dielectric frequency response (DFR), also known as frequency domain spectroscopy (FDS). DFR is an established laboratory testing procedure that has been adapted for field use through Megger's innovative efforts in the IDAX product line.
DFR involves measuring capacitance and dissipation factor (tan delta or power factor) across multiple frequencies. The measured DFR curve depends on the geometry of the insulation, moisture content, oil conductivity, and temperature. By extending the curve approximation to a reference material model, IDAX calculates moisture content in solid insulation, oil conductivity at a reference temperature of 25°C, and tan delta/power factor at a reference temperature of 20°C.
These calculations use ITC (individual temperature correction), another Megger innovation, to convert test data from the tested object’s temperature to reference temperatures. The IDAX software includes frequency correction considering ITC, specifically designed for evaluating measurement transformers and bushings.
Thanks to a new approach combining time and frequency domain data, IDAX provides the shortest measurement time on the market for complete DFR measurement from 1 kHz to 10 μHz. Separate reference models are selected for each data set (time or frequency) before transformation and merging, eliminating artifacts caused by approximation or incomplete data sets.
IDAX is extremely easy to use, with an automated testing process and results presentation using a clear 'traffic light' system.
The IDAX DFR method is now part of international guidelines and standards.
