Automatic Voltage Regulator (AVR) is one of the main component of an Alternator. Main functions of AVR is to built-up the rated voltage and maintain the output voltage within the limit at no-load and on-load conditions. There will not be any output or abnormal output when an AVR fails. What are to be checked before replacing an AVR Disconnect the AVR. Then check all windings of alternator for continuity and insulation resistance. If any defect is found then rectify it. Never replace the AVR if any winding is having a very low IR value or winding is defective. Connect the AVR after rectifying the defect and then start the machine. If there is no output voltage go to step 2. Check the condition of diodes in RRA. If found defective then replace the defective diode of Rotating Rectifier Assembly (RRA). Start the DG Set. If alternator does not develop voltage go to step 3. Then run the alternator at idle speed without connecting AVR and note the output voltage. The output voltage must b
I am working at a small firm engaged in repairing and rewinding of electrical machines like Motors and Alternators. I am in this industry for the past 13 years. Here I am sharing some of my experience with AC Motors and Alternators. I hope it will be helpful to those in similar field and will help me when they share their experiences here.