DEVICE FOR PROTECTION OF THREE-PHASE BRIDGE RECTIFIER AND EXCITATION WINDING OF BRUSHLESS SYNCHRONOUS GENERATOR'S ROTOR

摘要

Invention refers to the protection of rotor excitation winding and rectifying diodes of AC generator against overvoltages. The aim of the invention is to increase the reliability of the system by means of introducing a controlling device instead of the arrester, which starts to operate when the voltage applied exceeds a certain preset value U2max. When the voltage on Zener diode 10 exceeds its breakdown value the capacitor 9 is charged and IGBT transistor 7 opens starting to discharge the shunt capacitor 5 of the excitation winding 2 and the voltage on excitation winding 2 is reduced. When the voltage falls below the minimum value U2min , which is set by voltage divider 8, the capacitor 9, starts to discharge, transistor 7 closes and the voltage on excitation winding increases to U2max. The protection device do not operate if the excitation voltage is below the preset value U2max.