engineering standard specification ontarioextportal.vale.com/eng/sud/standards/pdf/spec-83063.pdfit...

ENGINEERING STANDARD SPECIFICATION Ontario

TITLEMATERIALS ENGINEERING AND TESTINGCRITICAL FANS - VIBRATION QUALITY REQUIREMENTS

VALE #SPEC-83063

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1.0 PURPOSE

This standard has been developed to ensure that machinery monitoring and protection systems willbe installed on New Motor/Fan Assembly deemed to be critical (Criticality Score A ref. ZBM ECAPlaybook) to the business.This specification outlines the Vale standard system. It is a comprehensive asset protection andmachinery vibration analysis system, tightly integrated with the distributed control system (DCS), toprovide Operations personnel access to real-time plant condition information, and Maintenancepersonnel the necessary data for optimum predictive maintenance planning.

2.0 MOTOR AND/OR FAN REQUIRED TRANSDUCERS

Fan Type Motor Non-DriveEnd

Motor Drive End(fixed Bearing)see note

Fan Non-Drive End(fixed Bearing)see note

Fan Non-DriveEnd

Centrifugal SimplySupported RollingElement Bearings

1X seismicprobes, (1 in the RadialHorizontal position)

2X seismicprobes, (1 in the radial,Horizontal position and1 in the Axial position)

2X seismicprobes, (1 in the radial,Horizontal position and 1in the Axial position)

2X seismicprobes, (1 in the radial,Horizontal position and 1in the Vertical position)

All Fans equippedwith Oil SleeveBearings

2X ProximityProbes.(see detail on mountingpositions)




CentrifugalOver- HungRolling ElementBearings

1X seismicprobes, Radial, (1 in thehorizontal position and 1 inthe Vertical position)

2X seismicprobes, (1 in the radial,horizontal position and1 in the Axial position)

2X seismicprobes, (1 in the radial,horizontal position and 1in the Axial position)

2X seismicprobes, (1 in the radial,horizontal position and 1in the Vertical position)

Axial FlowSimply SupportedRolling ElementBearings

1X seismicprobes, (1 in the Radialhorizontal position and 1 inthe Vertical position)




Axial FlowOver-HungRolling ElementBearings

2X seismicprobes, Radial, (1 in thehorizontal position and 1 inthe Vertical position)




Cooling TowerBelt DriveRolling ElementBearings

1X seismicprobes, (1 in the radial,horizontal position and 1 inthe Vertical position)


2X seismicProbes, 1 in the Radialplane, (Horizontalposition) and 1 in theAxial position

2X seismicProbes, 2 in the Radialplane, (1 in theHorizontal and 1 in theVertical position)

Cooling TowerGearboxRolling ElementBearings

1X seismicProbe in the Radialposition (HorizontalOrientation)


N/A 3X seismicProbes, 2 in the Radialplane, (Horizontal andVertical) and 1 in theAxial position

Note : - All Fan Assemblies shall be equipped with 2 Keyphasers.- All Axial probes are to be mounted on the fixed bearings.

(This grid assumes that the axial probes are mounted on the Motor-Drive End and Fan Non-Drive End.)



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3.0 TRANSDUCER INSTALLATION AND MOUNTING

Keyphasor

For Direct coupled installation the keyphasor bracket shall be mounted on the motor and reading offthe motor shaft speed. Do not install on the driven (fan) side.

If the assembly has a speed reducer/increaser such as a gear box or a belt drive with differentsheave sizes the keyphasor shall be mounted on the driven (fan) side.

Figure 1: Keyphasor mounting arrangement for direct coupled fan assembly.

Vibration transducers mounting

Mounting surfaces for the vibration transducers and their housing shall be machined to ensure totalcontact. Each transducer is to be mounted on the bearing housings and aligned with the shaft axis.(see Figures 2 – 5)



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Figure 2: Sensor position nomenclature

Figure 3: Example of proper and improper transducer location



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Figure 4: Photograph showing proper location of vibration transducer on a motor.

Figure 5: Example of poor sensor location (never install on motor fin and should be in line withcenterline of bearing)

Vertical

Horizontal



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4.0 DUAL KEYPHASOR MOUNTING

Where dual Key Phasor is to be mounted, installation should be in such where both keyphasors are90 Degrees apart.

1. This enables direction of rotation to be determined.2. In event that one of the keyphasor fails, the shaft speed is still available.



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5.0 GUARDING

Guarding shall be fabricated so that rotating shafts are covered but the pillow blocks are exposed.This will permit personnel to grease, monitor for vibration or perform any maintenance ortroubleshooting safely while machinery still in operation. (Figure 6-7)

Figure 6

Figure 7

With guarding in place leaving bearingsexposed in order to take vibration readingsvia hand-held vibration Data Collector.



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6.0 ACCEPTANCE CRITERIA

Resonance Avoidance Rotating Equipment Less Than 3800 RPM• The commissioned fan system shall have no natural frequencies (resonance) between

rest and 143% of the highest operating speed and there shall not be a simple harmonic ofthe blade passing frequency. Each fan wheel assembly excluding the blades shall bestatically and dynamically balanced.

• The Vendor shall provide the estimated first shaft critical speed for the fan. Shaft criticalspeed is defined as the speed which coincides with the first fundamental naturalfrequency of the fan shaft in bending when the shaft is mounted to the impeller and isassumed to be supported on infinitely stiff supports at the bearing locations. ie. Bumptest, coast down test, shake test, other.

• The vendor shall complete a design resonant speed analysis accounting for the stiffnessof the bearing races, bearing housings, steel bearing pedestals and structural steelsupport. The design resonant speed shall be no less than 1.43 times the maximumcontinuous operating speed at the fan design temperature. The first resonant frequencyof the assembled fan system shall be demonstrated not to be between 0 and 1.43 ofmaximum rotating speed of the fan when mounted on the site foundation. The Vendorshall indicate the methodology to demonstrate this. A report describing the analysis,assumptions and the analysis results is to be issued to Vale for acceptance uponcompletion of shaft design and final bearing selection.

• The vendor shall complete a torsional critical speed analysis of the entire motor, floatingshaft and fan rotor system. The torsional critical speed shall not fall within avoidanceranges of ±10% of 1 times and 2 times anticipated running speeds (VFD). In the eventthat the torsional critical speed falls within the above defined avoidance band, the fanvendor shall modify the coupling selections, shaft and/or the fan rotor. The vendor shallsubmit a report to Vale for acceptance upon completion of the shaft design. This reportshall include a graphic display of the mass-elastic system, tabulation identifying the massmoment torsional stiffness for each component in the mass-elastic system and a graphicdisplay of torsional critical speeds and deflection.

• The impeller design shall have ample strength to withstand the imposed stresses andoperating duty. Stresses due to centrifugal loading shall be calculated by finite elementanalysis. The vendor is required to submit a finite element analysis (FEA) report to Valefor acceptance upon completion of the impeller design. The FEA report shall describe themodeling techniques, identify the stress levels in the impeller and demonstrate the safetyfactor on material yield strength and fatigue strength. The report shall include adescription of the boundary conditions, applied loads, any assumptions made in themodeling and a plot of the FEA wire frame mesh. Based on the vendor’s standard design



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practice, the maximum allowable von Mises design stress, as a percentage of thematerial yield strength shall be stated in the proposal for all materials used in the impeller.

• A fan impeller natural frequency test (bump test) of the as-built impeller shall becompleted in the fan vendor’s factory prior to shipment. Mode shapes at resonantfrequencies in the region of the fan’s operating speed, and blade passing frequencies,shall be identified and documented. Test results shall be included in the inspectionreports.

• The impeller shall be positively attached to its support shaft. The vendor shall state in theproposal the method of impeller to shaft attachment.

• The vendor’s standard radial and axial run out tolerances shall be stated in the proposal.These run outs shall be inspected and complied with at the factory, and recorded in theQuality Assurance documentation.

Vibration Severity - Overall AmplitudeRoller element bearings:

The overall vibration severity shall be measured on the bearing housings when the fan ismounted on the foundation or the Vendor’s test stand. Severity shall be measuredradially, in the direction of least stiffness, and axially. Refer to ISO 10816-1:1995 (E).The frequency range in accordance with the ISO 10816-1:1995 (E), the overall rms radialvibration velocity shall not exceed 1.8 mm/s rms. If these requirements cannot be met, theVendor shall complete necessary stiffening so that compliance can be demonstrated.

Oil sleeve bearings:The overall vibration severity shall be measured on the bearing housings when the fan ismounted on the foundation or the Vendor’s test stand. Severity shall be measuredradially.

For the purpose of acceptance, maximum shaft amplitude in peak-to-peak mils shall not

exceed:

ex: for a 3600 rpm fan √(12000/3600) = 1.8 mils peak to peak Mechanical runout should not exceed0 0.450 mils (1.8 x 25% = 0.450)

ex: for a 900 rpm fan √(12000/900) = 3.6 mils (where maximum would befault to 2 mils peak to peak) Mechanical runout should not exceed 0.500 mils (2 x 25% = 0.500)



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or 2 mils whichever is less for a frequency range of 30% of operating speed to 60,000cpm. In this criteria, displacement amplitude is measuring shaft motion and includesmechanical runout which can be no more than 0.25 times the allowed displacement.

If these requirements cannot be met, the Vendor shall complete necessary stiffening sothat compliance can be demonstrated.

Rotor Imbalance

• The maximum residual unbalance for the motor and fan rotor without blades shall be inaccordance with ISO 1940 (1974) with balancing to grade G2.5.

• All fan blades shall be moment balanced in pairs and shall be match marked and shippedseparately. Identification markings shall be clearly stamped into the bottom of each blade.

• The maximum residual unbalance of the assembled fan rotor with blades shall be inaccordance with ISO 1940 (1974) with balancing to grade G2.5.

Run and Performance Testing

The Vendor shall provide all the testing as described in this section. Vale representatives mayrequire to be present during all testing. If it is determined that the fans do not meet the quotedfan performance, it shall be the responsibility of the fan manufacturer to recommend andimplement corrective measures and then retest the fans to demonstrate that the fan performanceis acceptable.

Mechanical Run Acceptance Tests

Factory run acceptance tests must be completed by the Vendor and witnessed and accepted byVale’s Vibration Specialist and Representatives. If factory run tests cannot be conducted due tosize or power limitations at the vendor’s facility, an alternate scope for site run tests shall beproposed. The Vendor shall outline in their bid their methodology for testing. To complete thistesting the fan shall be erected on the Vendor’s test stand and satisfactory operation shall bedemonstrated with Vale representatives in attendance. The following tests shall be documentedand shall be made with full nameplate voltage to the motor. Resonance Test and VibrationSeverity Tests will be conducted as part of the Mechanical Run Acceptance Test and sitecommissioning tests.



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Resonance Test

The first resonant frequency of the assembled fan system shall be demonstrated not to bebetween 0 and 1.43 of maximum rotating speed of the fan when mounted on the site foundation.The Vendor shall indicate the methodology to demonstrate this. ie. coast down test, shake test,other.

Vibration Severity

Roller element bearings

The overall vibration severity shall be measured on the bearing housings when the fan ismounted on the foundation or the Vendor’s test stand. Severity shall be measured radially, in thedirection of least stiffness, and axially. Refer to ISO 10816-1:1995 (E).

(i) Frequency Range

The frequency range in accordance with the ISO 10816-1:1995 (E), the overall RMSradial vibration velocity shall be less than the high limit for A range for Class IIImachines and shall not exceed 1.8 mm/s RMS. If these requirements cannot be met,the Vendor shall complete necessary stiffening so that compliance can bedemonstrated.

(ii) Sensitivity

An out of balance that will result in a centrifugal force that is 5% of the rotor massmultiplied by the RPM/900 shall not increase the RMS vibration severity measured inthe direction of most influence by more than 1 mm/sec when the fan is installed. Ifthis requirement cannot be met the vendor shall complete necessary stiffening sothat compliance can be demonstrated

Example: Assume a fan with a rotor weighing 1000 kg. operates at 720 RPM and hasa correction radius of 630 mm:

CF * 5% * RPM/900 = OBM/g * R * omega2

Where CF = centrifugal force (kg)

OBM = out of balance mass (kg)

G = gravity constant [9.81 m/(s*s)]



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R = radius to OBM (m)

Omega = angular velocity (radians/s)

Then: 1000 * 5/100 * 720/900 = OBM/9.81 * 0.63 * (2 * 3.142 * 720/60)2

OBM = 0.110 kg.

An out of balance mass of 110 grams acting at a radius of 630 mm must not increasethe RMS vibration severity by more than 1 mm/s.

Or

Sensitivity must be less than 0.91 mm/s per 100 grams at 630 mm radius.

Sleeve bearings:

An out of balance that will result in a centrifugal force that is 5% of the rotor mass (impellor plusshaft) multiplied by the RPM (900) shall not increase the peak to peak shaft displacement in thedirection of the most influence by more than 1 mil.

This will be verified by means of either factory test on the fan Vendor’s test stand or by a test onsite. If the fan fails this test, the fan Vendor shall complete the necessary stiffening so that therequired margin can be demonstrated.

Other acceptance requirements

• The impeller shall be positively attached to its support shaft. The vendor shall state in theproposal the method of impeller to shaft attachment.

• The vendor’s standard radial and axial run out tolerances shall be stated in the proposal.These run outs shall be inspected and complied with at the factory, and recorded in theQuality Assurance documentation.

7.0 INSTRUMENTATION

All new equipment is to have its vibration monitored and protected by Bently Nevada’s systems.

· 3500 or 2300 Vibration Rack

· Bently Nevada Sensors



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· Bently Nevada System 1 data recording system

8.0 REFERENCE DOCUMENTATION

The following documents are related to this specification and shall be used to their latest revision:

ISO 1940/1 Balance quality requirements for rotors in a constant (rigid) stateAPI 670 Machinery Protection Systems

ISO 10816 Mechanical vibration — Evaluation of machine vibration by measurements onnon-rotating parts

PGS-xxxxx Equipment Criticality Analysis (ECA)



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9.0 REVISION AND TRANSITION NOTES

Revision notes describe: what was changed, and if applicable, why it was changed, and the plan toimplement the change, including whether changes are retroactive.Note: The revision notes are a summary of the changes and may not necessarily be a complete list.

A risk code is entered for each revision and if applicable, the revision notes will describe how riskwas addressed for the revision.RiskCode Risk Category

A This revision is a minor change and/or introduces no risk.

B Risk has been addressed for this revision by the reviewer and approver. Low risk or no new hazards identified.

C For this revision, a PHR or other risk management tool has been used to address risk and minimize hazards. Thisrisk assessment has been documented and is available through Central Engineering.

Rev# Revision Notes Risk

CodeApproved

byReviewed

byIssue Date

YYYY/MM/DD

1 New Standard Specification A P. Belzile P. Wozny 2019/10/31

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