Research on the Field Dynamic Balance Technologies for Large Diesel Engine Crankshaft System

In order to reduce the unbalancing mass and the accompanying unbalancing vibration of diesel engine crankshaft system, the field dynamic balancing method and its key technologies are presented in the paper. In order to separate the unbalancing vibration signal from the total vibration signal of crankshaft system, the fundamental frequency signal fitting principle based on the least square method was introduced firstly, and then wavelet noise reduction method was applied to improve the signal fitting precision of least square method. Based on the unbalancing vibration signal analysis and assessment of crankshaft system, the influence coefficient method was applied to calculate the value and phase of the equivalent unbalancing mass in flywheel. To easily correct the unbalancing condition of crankshaft system, the unbalancing adjustment equipment was designed based on the flywheel structure. The balancing effect of field dynamic balancing system designed for the large diesel engine has been verified by field experiments.

Research on the Field Dynamic Balancing Technology and Instrument for a High Speed Cantilever Rotor

The principle of balancing a high speed cantilever rotor at full speed has been put forward by low-speed and high-speed balancing. The portable field dynamic balancing instrument based on the microcontroller is discussed from the hardware, the software and the signal process in detail. With the developed instrument, the whole-machine balancing experiment was conducted on a saucer-separating centrifuge RJ-460. The vibration of the saucer-separating centrifuge decreased from 3.8mm/s to 0.3mm/s at 1200r/min and decreased from 9.8mm/s to 0.6mm/s at 7200r/min. The experimental results indicated that the principle of balance is correct and the designed instrument is reliable and promising.