4. Exciter excitation current
(1) One or two of the rectifier components are disconnected in the forward and reverse directions. Check with a multimeter and replace the damaged components.
(2) The main generator or exciter excitation winding is partially short-circuited, and the DC resistance value of each pole coil is measured. Replace coils with short-circuit faults.

5. Steady-state voltage regulation
Faulty automatic voltage regulator Check and correct fault.

6. Vibration
(1) Poor docking with the prime mover Check and correct the docking. After the bolts are tightened, ensure that the axis of the generator and the prime mover are aligned and concentric.
(2) The dynamic balance of the rotor is not good. After the rotor is rewound, the dynamic balance should be found.
(3) The main generator excitation winding is partially short-circuited. Measure the DC resistance of each pole to find out the short-circuit fault point. Replace the coil.
(4) If the bearing is damaged, the bearing cover is generally overheated. Replace the bearing.
(5) The prime mover is faulty, check the prime mover.