MOTOR WITH JOURNAL BRG. THEN VOITH HYDRAULIC COUPLING WITH SCOOP CONTROL COUPLED WITH FAN WHICH IS SIMPLY SUPPORTED ON JOURNAL BRG. FAN HAS IMPELLAR WITH 11 VANES. INLET GUIDE VANES ARE PROVIDED AT SUCTION.
1.Initially a 3kg weight (previous balancing wt.) was already in ID Fan-4c and vibration was 125 microns peak to peak (phase angle coming 345deg).
2.At initial trial 3kg weight was removed and vibration was taken. Vibration 230 microns phase angle 343 deg.
3. At same location of 3kg weight ,we added 7 kg weight as calculated by balancing diagram. But vibration didn't reduced. Vibration was 142 microns 260 deg.
4.In next trial as per balancing diagram we removed 7 kg weight and added 6.5 kg at 34 deg clockwise but vibration increased instead of reducing.Vibration was 210 microns at 250deg.( Vibration varying from 160 to 210 microns pk to pk).
5. Since balancing was not responding ,next weight came 4.7 kg in clockwise 42 deg but we placed it anticlockwise 42 deg.Vibration reduced to around 125 microns. Variation in vibration is there from 80 -120 microns pk to pk .(overall via. trend attached).Also at 85% scoop when fan speed was 508 rpm vibration was varying from 80 to 120.But with 100% scoop with rpm 560 rpm vibration was nearly constant at 100microns.