The surge comparison tester is a universal type instrument capable of testing
single- and three-phase machine windings. Single-phase windings should
be tested in pairs whereas the three-phase windings should be tested two
phase windings at a time. Single-phase and three-phase machine windings of
various sizes can be tested as shown in the connection diagram of Figure 10.44.
The waveshapes for typical winding faults for the wye- and delta-connected
machines are shown in Figure 10.45.