jv 00374 rev i .pdf

Vibration Measurement and Analysis on TC 10 Motor 2 and TC 20 Motor 2

Site : Lumut Port Malaysia (Lekir Bulk Terminal)

Survey Date : 11th October 2013 Report Date : 28th October 2013

Reported For : En Mohd Daud Work Supervisor

Lekir Bulk Terminal

Reported By : En. Mohd Fazli Jaafar En. Mohamad Asyraf Halim

Vibration Analyst Category II, Mobius Institute of Australia

Verified By : Haji Ahmad Fawzal B. Mohd Noor Managing Director, Msc Condition Monitoring (UK) Vibration Analyst Cat III

AF Condition Monitoring (M) SdnBhd No 15-1 JalanKenanga

SD 9/4 Bandar Sri Damansara 52200 Kuala Lumpur

Tel. +603-6273 4078 / 9 Fax.+603-6273 4080

Email: [email protected] Website: www.afcm.com.my

Technical Report

AFCM

CERTIFIED TO ISO 9001:2008 CERT NO. AR4928

Lumut Port (Lekir Bulk Terminal) 1. Vibration survey and condition verification

1.1. Background

Two units of plan conveyor motors at Lumut Port which are Trestle Conveyor 10 (TC 10 M02) and Trestle Conveyor 20 (TC 20 M02) experiencing a high vibration. AFCM were ask to make a vibration measurement and analysis on these two motors. It was discovered that the high vibration on both of the motor are fluctuating and the level are noticed on the floor.

1.2. Machine Outline

Figure 1: TC 10 AF010-M02 Motor Layout and Vibration Measurement Locations

Gearbox DE

Motor DE Motor NDE Coupling

Gearbox NDE

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Lumut Port (Lekir Bulk Terminal)

2. Vibration Measurement Results 2.1. TC 20 Motor 02

2.1.1. Vibration data

The absolute vibration is measured at all bearings at condition of normal operation on TC 20 Motor 02.

Location Orientation Overall mm/s rms

1X mm/s rms

Motor NDE

Horizontal 25.88 25.8 Vertical 6.215 5.866

Axial 2.301 1.122

Motor DE Horizontal 11.12 11.04

Vertical 5.078 4.569 Axial 4.054 3.667

Gearbox DE Horizontal 2.767 0.337

Vertical 3.392 0.267 Axial 0.847 0.312

Gearbox NDE


Axial 5.171 1.938 Table 1- Absolute casing vibration result for TC 10 Motor 02

It can be observed that from above table, most of the dominant vibration were contributed from the motor side. The horizontal direction experienced higher level of vibration due to flexibility of position of the machine that mounted vertically. Based on the ISO 10816-3, this machine exceeded the danger threshold (zone D). This phenomena are clarified on the spectrum below.

Dominant vibration on machine

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2.1.2. Vibration Spectrum

As shown on the spectrum waterfall plot below, the vibration is actually highly fluctuated from 20 mm/s to less than 10 mm/s, on both motor sides during measurement.

Figure: TC 20 Motor 02 NDE Horizontal

Figure: TC 20 Motor 02 DE Horizontal

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After studying the nature of the oscillations, the dominant vibration were contributed by 1X running speed of the machine. The level of 1X vibration fluctuating while the running speed is constant. Further analysis required to identify the cause of fluctuating symptom. It is suspected that those present fluctuation is caused by beat phenomenon.

Acceleration waveform above shows that the vibration spectrum for the motor had a sidebands with 0.248 Hz. The frequency of the peaks with 24.69 Hz is corresponding to the speed of the motor, and 24.43 Hz is suspected belongs to the running speed of TC 10 motor 01.

It is believe that the beating effect that occurs on this machine is caused by an interference from another machine that is closely spaced.

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2.2. TC 10 Motor 02

2.2.1. Vibration data The absolute vibration is measured at all bearings at condition of normal operation on TC 10 Motor 02.

Location Orientation Overall 1X

Motor NDE


Axial 5.272 5.093

Motor DE Horizontal 6.650 6.130

Vertical 3.349 3.214 Axial 3.142 2.972

Gearbox DE Horizontal 2.750 0.915

Vertical 3.392 2.667 Axial 4.433 2.960

Gearbox NDE


Axial 3.690 2.658 Table 1- Absolute casing vibration result for TC 10 Motor 02

From above table, most of the dominant vibration were contributed by the motor side. The horizontal and vertical direction experienced high level of vibration due to fluctuation of the vibration level. This phenomena are clarified on the spectrum below.

Dominant vibration on machine

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2.2.2. Vibration Spectrum

As shown on the spectrum waterfall plot below, the vibration is actually fluctuated in the range of 8 mm/s to 5 mm/s rms.

Figure: TC 10 Motor 02 NDE Horizontal

Figure: TC 10 Motor 02 NDE Vertical

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After studying the nature of the vibration characters, we observed that this machine is having similar symptom as TC 20 Motor 02.

3. Recommendation

Based on our findings, this beating phenomenon is induced by the position of two closely located machines which are Motor 01 and Motor 02.

To reduce or eliminate this beating effect that cause the structure to vibrate fluctuately, it is advisable that action can be implement on the machine without a lot of structure modification by installing a vibration isolator, to prevent the transmission of mechanical vibrations into the machine floor. The isolator (spring) functioning with a minimum of 1 inch or 25.4 mm compression mounted at each sides of machine steel frame.

Picture below shows typical design on how the vibration isolator was used to support heavy equipment.

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Pictures below showed two types of vibration isolator which are commonly installed on identical closely spaced machines that operated in parallels. It is known as proven results in order to reduce and isolate the transmission of vibration from mechanical equipment through a floor structure of mechanical equipment and at the same time it also to protect equipment from damage during any seismic activity.

Figure 1: Mitigation example on existing structure.

Figure 2: Typical design isolator for newly commissioning machine.

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4. Appendix

4.1. ISO 10816-3

Evaluation of machine vibration by measurements on non-rotating parts Part 3: Large machines with rated power above 300 kW and not more than 50 MW; electrical machines with shaft height H 315 mm. Velocity

Vibration Level Description Acceptable Less than 2.3 mm/s RMS Warning Between 2.4 mm/s RMS and 4.4mm/s RMS Alert Between 4.5 mm/s RMS and 7.0mm/s RMS Danger Higher than 7.1mm/s RMS

Displacement

Vibration Level Description Acceptable Less than 82m pk-pk Warning Between 82 and 158m pk-pk Alert Between 158 and 251m pk-pk Danger Higher than 251m pk-pk

Table: Classification of vibration severity zones for machines of Group 1: Large machines with rated power above 300 kW and not more than 50 MW; electrical machines with shaft

height H 315 mm.

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