3. MakeFLENDER ModelKMP-440 Main Gear Box TypePLANETARY GEAR BOX Serial Number181.304.008.2.1 Rating1,700.00 KW Main Gear Box Ratio30.6 Input RPM994.00 RPM Output RPM32.40 RPM Oil Quantity5200.00 Ltr Lubrication SystemFORCED Equipment specification: Section-Raw Mill-II Equipment Name-Raw Mill Main Drive Gear Box Gear box details-SAP equipment no. 10010729

4. 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

5. 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.

6. 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:-

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

8. LINE-2 Equipment Vibration Report VRM LINE-2 LocationDirectionUnits Value on 30.10.2013 Value on 26.11.2013 Value on 26.12.2013 Value on 11.1.2014 Value on 17.1.2014 After BD Value on 22.1.2014 MOTOR MOTOR NDEAAxialmm/sec1.321.851.391.71.251.29 MOTOR NDEHHorizontalmm/sec0.751.10.770.981.20.84 MOTOR NDEVVerticalmm/sec1.50.910.940.820.840.86 MOTOR DEAAxialmm/sec1.51.82.12.32.71.5 MOTOR DEHHorizontalmm/sec2.242.391.842.032.110.89 MOTOR DEVVerticalmm/sec1.892.142.111.882.51.5 GEAR BOX G.B. INPUT DEA1Axialmm/sec3.493.142.623.023.061.97 G.B. INPUT DEH 1Horizontalmm/sec5.786.646.145.356.425.64 G.B. INPUT DEV1Verticalmm/sec6.346.544.635.686.064.37 G.B. INPUT DEH2Horizontalmm/sec5.266.915.765.74.793.63 G.B. INPUT DEV2Verticalmm/sec4.84.9255.774.683.61 G.B. BODY DEH 3Horizontalmm/sec6.264.076.065.255.643.02 G.B. BODY DEH 4Horizontalmm/sec4.583.94.785.484.824.17 G.B. BODY DEH 5Horizontalmm/sec4.223.684.24.933.142.31 Vibration Trend (30.10.2013 to 22.01.2014)

9. VIBRATION SIGNATURE ANALYSIS Key in The Source of problem identification

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

11. Time Wave Form

12. Waterfall Diagram

13. Summary of the Gearbox Shaft Speeds

14. 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

16. Damaged Planet Gears

17. Planet Gear Bearing BRG,ROLLER,23244- CCW33,SKF