Recommended Practice on Electric Submersible System Vibrations

API RECOMMENDED PRACTICE 11S8 SECOND EDITION, OCTOBER 2012

Recommended Practice on Electric Submersible System Vibrations

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API RECOMMENDED PRACTICE 11S8 SECOND EDITION, OCTOBER 2012

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Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms and Definitions 1

4. Vibration Analysis 4

   1. Harmonic Motion 4

   2. Concepts of Vibration 6

   3. Sources of Vibration 7

   4. Control of Vibration 8

   5. Vibration in ESP Systems 9

5. Vibration Testing 10

   1. Vibration Limits 10

   2. Measurement of Vibration 10

Annex A (informative) Units Conversion 12

Annex B (informative) Relationship Between Displacement, Velocity, and Acceleration 15

Annex C (informative) Classification of Severity of Machinery Vibration 16

Bibliography 18

Figures

1. Relation of Frequency to the Amplitudes of Displacement and Velocity (USC Units) 13

2. Relation of Frequency to the Amplitudes of Displacement and Velocity (SI Units) 14

B.1 Displacement, Velocity, and Acceleration Relationship 15

Tables

1 Vibration Analysis of ESP Phenomena 7

1. Conversion Factors for Translational Velocity and Acceleration 12

2. Conversion Factors for Rotational Velocity and Acceleration 12

3. Conversion Factors for Simple Harmonic Motion 13

1. Vibration Severity Criteria (After ISO IS 2372: 1974) 16

2. Vibration Severity Criteria (After Training Manual IRD Mechanalysis, Columbia, Ohio) 17

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Recommended Practice on Electric Submersible Pump System Vibrations

1. Scope

   
   

   This Recommended Practice (RP) provides guidelines to establish consistency in the control and analysis of electric submersible pump (ESP) system vibrations. This document is considered appropriate for the testing of ESP systems and subsystems for the majority of ESP applications.

   
   

   This RP covers the vibration limits, testing, and analysis of ESP systems and subsystems.

   
   

2. Normative References

   
   

   The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

   
   

   API Recommended Practice 11S4, Recommended Practice for Sizing and Selection of Electric Submersible Pump Installations

   
   

   API Recommended Practice 11S7, Recommended Practice on Application and Testing of Electric Submersible Pump Seal Chamber Sections

   ISO 2372:1974 1, Mechanical vibration of machines with operating speeds from 10 to 200 rev/s—Basis for specifying evaluation standards (replaced by 10816-1:1995)

   
   

   William T. Thompson, Theory of Vibration, Prentice-Hall, Inc., Englewood, N. J., 1965, pg. 243.

   
   

3. Terms and Definitions

For the purposes of this document, the following definitions apply.

3.1

acceleration

a

A vector quantity that specifies the time rate of change of velocity, both linear and angular. Common units are in./sec2 (cm/sec2) and radians/sec2.

3.2

amplitude

The maximum value of a periodic quantity.

3.3

angular frequency

circular frequency

The frequency multiplied by 2, in radians per unit time, applicable to a periodic quantity.

3.4

balancing

A procedure for adjusting the mass distribution of a rotor so that rotating imbalance, as seen by vibration of the journals or the forces on the bearings at once-per-revolution, is reduced or controlled.

1 International Organization for Standardization, 1, ch. de la Voie-Creuse, Case postale 56, CH-1211 Geneva 20, Switzerland, www.iso.org.

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