The Recovery Voltage Method is based on established knowledge: the phenomenon of the polarization for oil/paper impregnated insulation. 

Many high voltage working people have made this painful experience: to short-circuit a high voltage capacitor (which was previously charged with a direct voltage), to measure a voltage approx. equal to 0 V, to believe the capacitor is completely discharged, later on to touch the connectors of the capacitor and to perceive that there is still voltage between the connectors! This voltage is due to the polarization of the insulation.
 

There are different types of polarization. In case of moist oil-paper insulation, there is a polarization due to the water molecules contained in the insulation. By applying a DC voltage, these molecules (which were electrically neutral) acquire a polarity and try to drift in the direction of the electrical field. That means, molecules are now energized . We can short circuit and afterwards open the circuit. Some energy is still stored in the molecules. We can measure a voltage due to this stored energy, which is called the "recovery voltage".

By this method, insulation condition is established by tracing the polarization spectrum from the results of the recovery voltage measurements.

The instrument, the Recovery Voltage Meter type RVM 5462, which is the successor of the very well known type RVM 5461, effectively completes the range of the conventional insulation diagnosis methods, e.g. dissipation factor tan8 and partial discharge measurements, oil analysis, and so on.

Our specialists will gladly advise you on the use of the method and of the instrument. Furthermore, they will help you for the analysis and interpretation of the results.