MakeFLENDER ModelKMP-440 Main Gear Box TypePLANETARY GEAR BOX Serial Number Rating1, KW Main Gear Box Ratio30.6 Input RPM RPM Output RPM32.40 RPM Oil Quantity Ltr Lubrication SystemFORCED Equipment specification: Section-Raw Mill-II Equipment Name-Raw Mill Main Drive Gear Box Gear box details-SAP equipment no

Problem Statement On dated 19/1/2014 at 7.30 PM, Raw Mill-2 tripped due motor high current, on diagnosis reason of motor high current was mechanical locking / main drive GB internals damage. Tripping of RM-2 Main drive & sudden abnormal sound from RM-2 main dive GB at 07:30PM stopped mill operation

Observation and Before stoppage analysis:- Problem started few day before with a cyclic abnormal noise, near VRM body. Source of noise was suspected either gearbox or some other source from mill inside body.

To Identify the problem detail observations and vibration analysis done. Following observations noted.  Gear Box oil temperature (65-68°C) & bearing Temperatures at Gear Box input (66-69°C), which was in permissible limit.  Oil analysis & WDA Report were normal tested on 16/1/2014.  Vibrations at Gear Box 5.5 to 7.0 mm/s, which was in permissible limit.  Grinding Pressure changes (80-95 bars) have not significant effect in pattern as well as amplitude.  Motor vibration level 1.0 to 2.0 mm/s, which was in permissible limit.  The Gear mesh frequency has no signification side band.  No bearing fault frequency observed in vibration signature.  Noise level was slightly high. Observation and Before stoppage analysis:-

Lube Oil :-Last WDA and Oil Analysis reports are normal attach as below Observation and Before stoppage analysis:-

LINE-2 Equipment Vibration Report VRM LINE-2 LocationDirectionUnits Value on Value on Value on Value on Value on After BD Value on MOTOR MOTOR NDEAAxialmm/sec MOTOR NDEHHorizontalmm/sec MOTOR NDEVVerticalmm/sec MOTOR DEAAxialmm/sec MOTOR DEHHorizontalmm/sec MOTOR DEVVerticalmm/sec GEAR BOX G.B. INPUT DEA1Axialmm/sec G.B. INPUT DEH 1Horizontalmm/sec G.B. INPUT DEV1Verticalmm/sec G.B. INPUT DEH2Horizontalmm/sec G.B. INPUT DEV2Verticalmm/sec G.B. BODY DEH 3Horizontalmm/sec G.B. BODY DEH 4Horizontalmm/sec G.B. BODY DEH 5Horizontalmm/sec Vibration Trend ( to )

VIBRATION SIGNATURE ANALYSIS Key in The Source of problem identification

Planet pinion gear rotational frequency 78 CPM observed dominating in vibration spectrum and time waveform analysis

Time Wave Form

Waterfall Diagram

Summary of the Gearbox Shaft Speeds

Breakage in teeth of planet gear, result in abnormal noise when hitting with its meshing gear. Dominating peaks in vibration spectrum and time wave at planet pinion frequency 78 CPM was clearly suggesting that abnormal noise must coming from planet gear and its bearing assembly. Possible abnormalities could be Increased Bearing clearances of planet gear, result in planet gear teeth hitting to root of its meshing gear and generating abnormal noise Vibration Analysis Outcomes

Damaged Planet Gears

Planet Gear Bearing BRG,ROLLER, CCW33,SKF