Dielectric Loss Test DiagramWorking Principle:
Power is input into the operation box equipped with overcurrent automatic tripping and zero-position interlock device to prevent sudden voltage application. The voltage is regulated by an auto-transformer and then input to the primary winding of the test transformer. According to the principle of electromagnetic induction, a voltage amplitude equal to the turns ratio between the secondary (high-voltage) winding and the primary winding is obtained - power frequency high voltage. This power frequency high voltage is rectified by a high-voltage silicon stack and filtered by a stabilizing capacitor to obtain DC high voltage, whose amplitude is twice the effective value of the power frequency high voltage.
Precautions:
1. When conducting high-voltage tests, at least 2 or more personnel must participate, with clear division of labor and mutual communication methods. A dedicated person should supervise the site safety and observe the test status of the test object;
2. The transformer and control box should be reliably grounded;
3. During the test, the voltage increase speed should not be too fast, and sudden full voltage power-on or power-off is strictly prohibited;
4. During voltage increase or withstand voltage tests, if any of the following abnormal conditions are found, the voltage should be immediately reduced, power should be cut off, and the test should be stopped. After identifying the cause, the test can be resumed. ① The voltmeter pointer swings significantly; ② A smell of burning insulation or smoke is detected; ③ Abnormal sounds are heard inside the test object.
5. During the test, if the test object short-circuits or breaks down, the overcurrent relay in the control box will operate. At this time, return the voltage regulator to zero, cut off the power, and only then can the test object be removed.
