What Causes a Generator Exciter to Fail?

Technician inspecting diesel generator alternator terminal connections

A generator exciter can fail because of winding overheating, insulation breakdown, moisture or contamination, loose connections, excessive excitation current, or faults elsewhere in the excitation system. But in our experience, low or no generator voltage does not automatically mean the exciter has failed. We normally check the AVR, wiring, excitation supply, and rotating diodes first. […]