Realisation of Ir

REALISATION OF INSULATION REISTANCE AND POLARISATION INDEX
( A TOOL FOR PREDICTIVE MAINTENACE & ANALYSES )

Insulation resistance measurement has been a common test and procedure adapted by service personnel for determination of condition of electric machineries, cables, breakers, switch gears etc   and   has been recommended and used for more than half a century to evaluate the condition of electrical insulation. The process being so common that its effectiveness is quiet often blurred by its simplicity? But being properly utilized it can be effectively utilized to improvement equipment insulation condition and thus overall life of the equipment. Simple individual insulation resistance measurements may be of questionable value, but the carefully maintained record of periodic measurements, accumulated over time, is of unquestioned value as a measure of critical aspects of the condition of the electrical insulation. The insulation measurement is a standardized procedure and should be evaluated on basis of those laid out procedures for effective analyses, here we would review the basic standards utilized in Insulation measurement, rectify many mistakes that are made during insulation measurement and understands it results.
Now the basic question is what insulation is. In common terms anything that resists the flow of current through and keeps the current to its path can be classified as a insulation. Insulation resistance is the capability of the electrical insulation of a winding to resist direct current. The quotient of applied direct voltage of negative polarity divided by current across machine insulation, corrected to 40 °C, and taken at a specified time (t) from start of voltage application. The voltage application time is usually 1 min (IR1) or 10 min (IR10). Its purpose is to evaluate the condition of the insulation between conductors and ground. By applying a direct voltage between the conductors (windings) and the casing of the electric motor (machine)...