Surge Testing

More accurately stated as surge comparison testing, this test is one of the few static electrical tests that can show the phase to phase insulation quality of a winding. Often a winding will “break down” under load, but perform flawlessly under no-load conditions.

A high voltage is discharged through the winding, measuring the rate of decay of the voltage. This is displayed on a special dual trace oscilloscope. By comparing one phase of the winding to another, any differences appear as a double image. A trained technician can analyze the display and determine if a fault condition is developing within the turns of the winding.

This test can be used to determine the condition of the insulation system and can find a fault before it becomes a critical failure. These tests can be done before or after a motor is disassembled as well as on-site.