The surge test can identify short-circuits between coils present on the same winding. It’s normally possible to identify 1 short-circuited coil over 200 turns. EDC has realized special systems for customers who needed to identify short-circuits of 1 coil over 3000 coils. The Surge test allows to detect the following faults:
- permanent short-circuited coils;
- no-permanent short-circuited between coils with production of discharges;
- presence of corona discharge;
- losses of insulation; ·losses due to above-normal parasitic capacitance.
The system performs a complete analysis of the response of the tested stator for each single pulse applied. The Surge Test consists of connecting in parallel the tested winding (inductance L) and a capacitor (with capacitance C). The capacitor is charged at the Vsg Voltage. The EDC Testing System analyses the evolution of the measured signal from the ends of the parallel L-C during time.
In the Surge Test standard version, the EDC system samples the signal and gets the following data:
- The value of the L INDUCTANCE coefficient.
- The value of EL ENERGY LOSS which measures the quantity of energy lost between two peaks pre-selected of the damped sinusoidal. The higher is the EL Value, the higher is also the energy loss so the sinusoidal will damp in shorter time
The RED CURVE shows a stator with 200 turns and 1 turn in short-circuit (NO-GO) and the BLUE CURVE showes a stator with 200 turns and 0 turn in short (GO).