3) In the shop, resonance frequency was confirmed and fine balancing was carried out to reduce 1st order vibration. By fitting balance weight on PTO shaft end at fore side and on flywheel at aft side, single amplitude was successfully reduced within the target value of 0.25 mm.
Fig. 15 shows the result of frequency analysis of vibration acceleration on both on the engine and the foundation putting rubber between them.
Fig.15 RESULT OF FREQUENCY ANALYSIS
4) Sea trial
Prior to sea trial, dynamic balancing was carried out on the engine on board ship, then, resonance frequency of 3rd vibration was confirmed in sea trial.
Fig.16 shows amplitude comparing data measured in shop bench and on board ship.
