It is important to stress that the insulation resistance of electric motors is measured regularly, so that it is possible to evaluate the storage conditions by analyzing them from the electrical point of view. Therefore, if possible drops in insulation resistance values are analyzed, storage conditions should be evaluated and corrected if necessary. In this way, the insulation resistance measurement must be performed in a safe area. In order to avoid the risk of electric shock, the terminals must be discharged before and after each measurement. If the motor has capacitors, they must be fully discharged.
It can be stated that the insulation resistance can be measured by means of a device called a megometer, with the motor completely stopped, cold and completely disconnected from the mains. It is indicated that each phase is previously isolated and tested in separate ways, so that a comparison is made between the insulation resistance in each phase. In order to test one of the phases, the other phases must be grounded MagPowr CYGNUS. Power cables, as well as wrenches, capacitors, and other equipment connected externally to the motor, have the ability to influence the measurement of insulation resistance.