Reasons and Solutions for Diesel Generator Set Vibration

The structure of the generator contains both electrical and mechanical parts, which can also be said to be a combination of mechanical and electrical. Therefore, its failure is divided into two analysis. The cause of the vibration fault of the generator is also divided into two parts. In general, generator vibration is caused unbalanced, electromagnetic or mechanical failure of the rotating part.

1. The unbalance of the rotating part is mainly caused by the imbalance of the rotor, the coupler, the coupling, and the transmission wheel (brake wheel). the treatment method is to find the rotor balance first. If there are large drive wheels, brake wheels, couplers, and couplings, separate the balance from the rotor. If there are large transmission wheels, brake wheels, couplings, separate and separate from the rotor to find a good balance. Then there is the mechanical looseness of the rotating part. For example, the iron core bracket is loose, the oblique key and the pin are loose, and the rotor is not tied tightly, which will cause the rotating part to be unbalanced.

The main problems of mechanical parts are as follows:

1. The linkage part of the shaft system is misaligned, the center line does no coincide, and the centering is incorrect. The cause of this failure is mainly caused by poor alignment and improper installation during the installation process. There is also a case where some of the center lines of the interlocking parts are coincident in the cold state, but after a period of operation, the center line is broken due to the deformation of the rotor fulcrum and the foundation, thereby generating vibration.

2. Gears and couplings associated with generators are faulty. This kind of failure mainly manifests as poor gear occlusion, serious tooth wear, poor lubrication of the wheel, skewing and misalignment of the coupling, tooth profiles of the gear coupling, incorrect tooth pitch, excessive clearance or serious wear, which will cause certain vibration.

3. The load dragged by the generator conducts vibration. For example, the turbine vibration of a steam turbine generator, the fan driven by then motor, and the vibration of the water pump cause vibration of the motor.

4. Defects in the structure of the generator itself and installation problems. This kind of failure mainly manifests as the ellipse of the journal, the bending of the shaft, the gap between the shaft and the bearing bush is too large or too small, and the rigidity of the bearing seat, the foundation plate, a part of the foundation and even the entire generator installation foundation insufficient, and generator and the base plate are insufficient. The fixing is not strong, the foot bolts are loose, and the bearing seat and the base plate are loose. The excessive or too small gap between the shaft and the bearing bush can not only cause vibration but also cause abnormal lubrication and temperature of the bearing bush.

The failure of the electrical part is caused by electromagnetic causes

1. Mainly include short-circuit of rotor winding of winding type asynchronous motor, stator wiring error of AC motor, turn-to-turn short circuit of synchronous motor excitation winding, misalignment of excitation coil of synchronous motor, rotor broken strip of cage asynchronous motor, rotor core deformation caused by stator and rotor air gap unevenness causes the air gap flux to be unbalanced and cause abnormal vibration.

When using the diesel generator set, the user will encounter abnormal noise and excessive vibration during the operation of the diesel engine. The following is the answer to the reasons and troubleshooting methods.