A programmable D-C high voltage ramped test system for electrical insulation

A technique is presented that uses a programmable dc high voltage test set to automatically ramp the high voltage at a preselected rate while continuously recording the resultant rotating machinery stator insulation current. The principal advantage of the ramp testing technique over the conventional stepped method is the greatly improved sensitivity and accuracy of the test results. In addition, the ramp test requires only one person to run the test and provides that person with better control and sufficient lead time when a failure point is approached to avoid damaging the insulation. A full discription of the test technique, interpretation of test results, and test set operation are included.