HD Technology Case Study packages... · SPM HD Spectrum shows high HDesv levels and a perfect match with bearing symptom BPFO for outer race damage. Fig 4. SPM HD trend graph HDm/HDc,

SPM Instrument Bulgaria ЕООD [email protected] www.spminstrument.com Str. Hadzhi Stamat Siderov № 35/А Tel.: 052-600 805, 625 080 Company № 1967/1995 9000 Varna, BULGARIA Fax: 052-600 333 © SPM 2017-11 CS_016B

CASE STUDY

HDTechnologyCaseStudy:Bearingmonitoring

ofAutogenousMillatAurubisBulgariaAD

By

Dobromir Dobrev and Nikolay Nikolaev

SPM Instrument Bulgaria EOOD

November, 2017

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Contents

1 Introduction ..................................................................................................................................... 3

2 Conclusionandsummary .................................................................................................................. 3

3 Applicationdescription ..................................................................................................................... 4

4 Systemsetup .................................................................................................................................... 6

4.1 Measuringequipment .............................................................................................................. 6

4.2 Measuringtechniques .............................................................................................................. 6

4.3 Condmastersetup ................................................................................................................... 6

5 Casedescription ............................................................................................................................... 6

6 Appendix ......................................................................................................................................... 9

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1 Introduction

This case study describes online condition measurements on a pinion drive-end bearing in Autoge-nous Mill No. 2 at a flotation plant. The measurements were carried out using the SPM HD shock pulse technology. The customer, Aurubis Bulgaria AD, is a leader in the non-ferrous metals business in Bulgaria and a leading copper producing plant in southeastern Europe. The company’s main activity is the produc-tion of copper anodes and copper cathodes, as well as byproducts such as sulfuric acid and iron sili-cate. The pinion gear shaft of the autogenous mill which is the subject of this case study works at low ro-tational speed (178 RPM). Both bearings are subjected to heavy loads and surrounded by sources of strong ambient noise. To the customer, long forewarning time for gearbox and pinion bearing fail-ures is essential. From a mechanical perspective, autogenous mills operate in a similar way to ball mills but use different media to break or grind the ore. Autogenous mills use larger rocks of ore in-stead of grinding balls made of steel or other materials to grind the ore.

2 Conclusion and summary

At the Aurubis plant, the online system Intellinova Compact INS06 is installed with the SPM HD and EVAM measuring techniques monitoring the mechanical condition of critical equipment. For the pinion drive-end bearing (measuring point no. P430MG02-PN-09), the SPM HD level graph shows a growing HDm trend and large fluctuations in the shock pulse amplitude from the beginning of the measurements on January 1st, 2015 until machine stoppage for bearing replacement on Au-gust 5th, 2016. HDm/HDc levels reach 35/-8 dB. This fluctuation is most likely related to dirt or load shocks. Over a period of eighteen months, HDm increased from 0 to 35 dB. Analysis of spectrum, time signal, and Colored Spectrum Overview shows bearing damage with ac-curately matching outer race symptom (BPFO). The installed bearing type is SKF 23180 CA.

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3 Application description

Autogenous mill №2 consists of an electrical motor, a two-stage gearbox, a pinion gear, and the drum with a girth gear.

Measuring points

Measuring point no. Position Sensor type

P430MG02-EM-01 Electrical motor - NDE bearing Shock pulse

P430MG02-EM-02 Electrical motor - DE bearing Shock pulse

P430MG02-EM-22 Electrical motor - DE bearing Vibration

P430MG02-GB-03 Gearbox - DE bearing/1st shaft Vibration

P430MG02-GB-06 Gearbox - NDE bearing/2nd shaft Vibration

P430MG02-PN-09 Pinion - DE bearing Shock pulse

P430MG02-PN-10 Pinion - NDE bearing Shock pulse

Fig 1. Autogenous mill №2 - 3D graphic.

P430MG02-PN-09 Pinion - DE bearing

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Fig 2. Autogenous Mill №2.

Fig 3. Autogenous mill №2 - measuring point locations, measuring point numbers, and installed sensors.

01

02 22 03

06

10

09

P430MG02-PN-09-Bearingdamage

Shock pulse sensor Vibration sensor

RPM measurement

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4 System setup

4.1 Measuring equipment

- Online monitoring system: Intellinova Compact INS06 - Shock pulse transducers: 4 x 44000 - Vibration transducers: 2 x SLD144S - Analog vibration transmitter: 1 x SLD733C (4-20 mA) - RPM sensor: 1 x proximity switch on motor drive side

4.2 Measuring techniques

SPM HD is the appropriate measuring technique for this application, because the monitored object is a low-speed machine with sources of strong ambient noise, making shock pulse analysis neces-sary.

4.3 Condmaster setup

Settings used in Condmaster Nova 2010.007 for the actual measuring point are as follow. The meas-uring technique used is SPM HD.

- Measuring time: Same as FFT measurement - Short / long time memory: Time signal and FFT - Upper frequency: 100 Orders - Lines in spectrum: 3200 - Symptom enhancement factor: 5 - Max RPM = 150 - Min RPM = 250

5 Case description

Measuring point P430MG02-PN-09 Pinion - DE bearing - SPM

Measurement took place from January 1st, 2015 to October 26th, 2016. From January 1st, 2015 to May 1st, 2016 the level graph shows increasing HDm levels and large fluc-tuations in the amplitudes of shock pulses. HDm/HDc levels reach approximately 35/-8 dB. There were big fluctuations in the Delta level; on average from 7 dB to 27 dB. The reason for these fluctuations is most likely related to dirt or load shocks.

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SPM HD Spectrum shows high HDesv levels and a perfect match with bearing symptom BPFO for outer race damage.

Fig 4. SPM HD trend graph HDm/HDc, from January 2015 - November 2016.

Bearing replacement Bearing damage

Fig 5. SPM HD Spectrum on April 30, 2016 – before bearing replacement.

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Time signal and Circular plot diagrams show very clear peaks. HD2esv level reached values around 19000 (for comparison, before the damage HD2esv levels were around 60) . The time signal clearly shows 9,73 peaks per 1 rev.

Colored Spectrum Overview shows BPFO match from the beginning of the measurements and ris-ing levels over time. There are some periods with lower amplitudes which are probably the result of reduced load on the mill. The green arrow shows the time of bearing replacement.

Fig 6. SPM HD Time Signal and Circular plot diagram on April 30, 2016 – before bearing replacement.

Fig 7. SPM HD Colored Spectrum Overview.

Bearing replacement

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6 Appendix

Below are pictures of the dismounted bearing. On the outer race surface, there are visible signs (scratches) of bearing damage.

Fig 8. Outer race.

Fig 9. Outer race.

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Fig 10. Outer race.

Fig 11. Outer race.

Documents

HD Technology Case Study packages... · SPM HD Spectrum shows high HDesv levels and a perfect match with bearing symptom BPFO for outer race damage. Fig 4. SPM HD trend graph HDm/HDc,