Debugging and Inspection of AC Generator

We have already shared the debugging tips for diesel engines, and once the diesel engine inspection is completed, it is time to debug and inspect the AC generator. How to debug the AC generator? Please refer to the following analysis and summary by Dingbo Power. The emergency backup power supply in the building is usually a three-phase AC diesel generator set.

(1) The coupling between the AC generator and the diesel generator requires that the parallelism and concentricity of the coupling be less than 0.05mm. In actual use, it is required to be slightly lower, about 0.1mm or less. If it is too large, it will affect the normal operation of the bearing and cause damage. The coupling should be fixed with locating pins, and the coupling situation should be retested before installation.

(2) When the sliding bearing generator is coupled, the height of the generator center should be adjusted slightly lower than that of the diesel engine center, so that the weight of the flywheel on the diesel engine will not be transferred to the generator bearing. Otherwise, the generator bearing will bear the additional weight of the flywheel, which is not conducive to the formation of the sliding bearing oil film, leading to heating and even burning of the bearing. The coupling of such generators cannot carry any heavy objects.

(3) When installing an AC generator, it is necessary to ensure that the cooling air inlet is unobstructed and to avoid the hot air discharged from entering the generator again. If there are louvers on the ventilation cover, the window should face downwards to meet the protection level requirements.

(4) Special attention should be paid to the uniform air gap between the stator and rotor in the mechanical coupling of a single bearing AC generator.

(5) According to the schematic or wiring diagram, select the appropriate power cable and use copper connectors for wiring. The copper connectors should be connected to the busbar, and after the busbar is tightened, the local gap at the joint should not exceed 0.05mm, and the distance between the wires should not exceed 10mm. Necessary grounding wires should also be installed.

(6) The wiring terminals inside the generator output box are marked with U, V, W, and N marks, which do not indicate that the actual phase sequence depends on the rotation direction. The certificate of conformity shows that UVW represents the actual phase sequence when rotating clockwise, and VUW represents the actual phase sequence when rotating counterclockwise.

(7) If the neutral points of each generator in the power supply system are connected to each other, or if the neutral point of the generator is connected to the neutral point of the transformer and its load, a neutral line current of three times the frequency will be drawn out from the neutral line during the operation of the unit. Therefore, it is necessary to measure the neutral line current of the generator under various load conditions that may occur during operation to prevent overheating. The line current should not exceed 50% of the rated current of the generator. If the neutral line power is too large, a neutral line reactor should be installed on the neutral line to limit it.

In order to break in the whole machine, the first load of the diesel generator set should be gradually loaded, with loading conditions of 25%, 50%, 75%, and 100% respectively. Before the 75% load, each stage should not be less than 30 minutes. Depending on the type of diesel generator set, it can be operated for a short period of time with a load of 110% to check the power performance of the diesel generator set. If you would like to get more information welcome to contact us via sales@dieselgeneratortech.com.