Laboratory Test for the identification of the PDIV through a pulses source

The PDIV Test analyses the quality of the product in terms of quality of the wire and of the level of isolation both winding to winding and windings to ground (or in the possible configurations, considering the kind of product in test). In short, it will identify in every test which is the inception/extinguish voltage of the Partial Discharge (the graphic on the left shows the PDIV Test and it’s found the product Partial Discharge Inception Voltage at about 1460V), which is a “natural” characteristic of the product, as overall result of the insulation characteristics of its components and of the process performed on it.

This method provides a MEASUREMENT OF THE QUALITY of the wire, of the insulation materials and the of the insulation process (for example, impregnation).

PDIV is very useful, for example, to check the improvement of the production insulation process, for example measuring the same product before and after impregnation or with different kinds/quantities of resin. Or it can be used to compare on the same product different suppliers of wire or insulation components.

The PDIV / PDEV test is particularly useful for motors that are powered by an Inverter with PWM signals; please refer to the norm EN 60034-18-41. In fact, it is demonstrated that with an Inverter the peak power voltage across motor windings can easily exceed in association with every period of PWM signals of 1500-2000Vpk. Because the switching frequency of the Inverter is in a range of 5KHz to 10KHz, the numbers of peak voltages (1500-2000Vpk) will be from 5000 to 10000 peaks per every second of functionality of the motor. If in association with these voltage peaks are present Partial Discharge inside the windings, it is demonstrated that the life of the motor will be reduced considerably.