The invention discloses a method for testing main insulation and turn-to-turn insulation of a low-
voltage scattered-wound variable frequency motor, and the method comprises the steps: S1, inputting 0-220V AC
voltage, and carrying out the
voltage regulation of the AC voltage; s2, boosting the voltage
signal after
voltage regulation; s3, transmitting the boosted voltage
signal through a common high-voltage
bus, and switching a test
branch by changing the state of a switching
relay; s4, when the turn-to-turn insulation is tested, increasing the voltage, by using the generated high-frequency pulse
signal, of the variable frequency motor winding, and testing the turn-to-turn insulation by means ofthe pulse signal; when the main insulation is tested, boosting, by using the sine voltage signal transmitted by the common high-voltage
bus, the variable frequency motor winding, and grounding the motor shell, and testing, by using the sine signal, the main insulation. The invention further provides a topological structure for testing the main insulation and the turn-to-turn insulation of the low-voltage scattered-wound variable frequency motor. According to the invention, by sharing the high-voltage
bus, the main insulation and the turn-to-turn insulation can be jointly tested in the same test
system, the experiment steps and the experiment equipment are reduced, and the experiment efficiency is greatly improved.