BS ISO 21940-21:2012
$198.66
Mechanical vibration. Rotor balancing – Description and evaluation of balancing machines
| Published By | Publication Date | Number of Pages |
| BSI | 2012 | 64 |
This part of ISO 21940 specifies requirements for evaluating the performance of machines for balancing rotating components by the following tests:
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test for minimum achievable residual unbalance, Umar test;
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test for unbalance reduction ratio, URR test;
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test for couple unbalance interference on single-plane machines;
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compensator test.
These tests are performed during acceptance of a balancing machine and also later, on a periodic basis, to ensure that the balancing machine is capable of handling the actual balancing tasks. For periodic tests, simplified procedures are specified. Tests for other machine capacities and performance parameters, however, are not contained in this part of ISO 21940.
For these tests, three types of specially prepared proving rotors are specified, covering a wide range of applications on horizontal and vertical balancing machines. An annex describes recommended modifications of proving rotors prepared in acccordance with ISO 2953:1985.[2]
Moreover, this part of ISO 21940 also stresses the importance attached to the form in which the balancing machine characteristics are specified by the manufacturer. Adoption of the format specified enables users to compare products from different manufacturers. Additionally, in an annex, guidelines are given on the information by which users provide their data and requirements to a balancing machine manufacturer.
This part of ISO 21940 is applicable to balancing machines that support and rotate rotors with rigid behaviour at balancing speed and that indicate the amounts and angular locations of a required unbalance correction in one or more planes. Therefore, it is applicable to rotors with rigid behaviour as well as to rotors with shaft-elastic behaviour balanced in accordance with low-speed balancing procedures. It covers both soft-bearing balancing machines and hard-bearing balancing machines. Technical requirements for such balancing machines are included; however, special features, such as those associated with automatic correction, are excluded.
This part of ISO 21940 does not specify balancing criteria; such criteria are specified in ISO 1940-1[1] and ISO 11342[3] (only low-speed balancing procedures apply).
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 9 | 1 Scope |
| 10 | 2 Normative references 3 Terms and definitions 4 Capacity and performance data of the balancing machine 4.1 General 4.2 Data for horizontal balancing machines 4.2.1 Rotor mass and unbalance limitations |
| 12 | 4.2.2 Rotor dimensions |
| 13 | 4.2.3 Drive |
| 14 | 4.2.4 Couple unbalance interference ratio: ……………………….. g·mm/(g·mm2) 4.2.5 Air pressure requirements: …………….. Pa, ………… m3/s. 4.3 Data for vertical balancing machines 4.3.1 Rotor mass and unbalance limitations |
| 16 | 4.3.2 Rotor dimensions 4.3.3 Drive |
| 18 | 4.3.4 Couple unbalance interference ratio: ……………………….. g·mm/(g·mm2) 4.3.5 Air pressure requirements: …………….. Pa, ………… m3/s. 5 Machine features 5.1 Principle of operation 5.2 Arrangement of the machine |
| 19 | 5.3 Indicating system 5.3.2 Amount indicators 5.3.3 Angle indicators 5.3.4 Operation of the indicating system |
| 20 | 5.4 Plane separation system 5.5 Setting and calibration of indication 5.5.1 General 5.5.2 Soft-bearing machines |
| 21 | 5.5.3 Hard-bearing machines 5.6 Other devices 6 Minimum achievable residual unbalance 7 Production efficiency 7.1 General |
| 22 | 7.2 Time per measuring run 7.3 Unbalance reduction ratio 8 Performance qualifying factors |
| 23 | 9 Installation requirements 9.1 General 9.2 Electrical and pneumatic requirements 9.3 Foundation 10 Proving rotors and test masses 10.1 General 10.2 Proving rotors |
| 25 | 10.3 Test masses 10.3.1 General |
| 31 | 10.3.2 Test mass for Umar test |
| 32 | 10.3.3 Test masses for URR test |
| 33 | 10.3.4 Permissible errors of test masses 10.3.4.1 Mass 10.3.4.2 Position |
| 34 | 10.3.5 Material 11 Verification tests 11.1 Requirements for performance and parameter verification 11.2 Duties of manufacturer and user 11.2.1 Examiner |
| 35 | 11.2.2 Readings 11.2.3 Condition of proving rotor and test masses 11.3 Requirement for weighing scale 11.4 Test and rechecks 11.5 Test speed 11.6 Test for minimum achievable residual unbalance, Umar 11.6.1 General 11.6.2 Starting-point 11.6.2.1 Plane setting for balancing 11.6.2.2 Initial unbalance |
| 38 | 11.6.3 Unbalance added 11.6.4 Readings 11.6.5 Correction 11.6.6 Reference change 11.6.7 Plane setting for Umar test 11.6.8 Test runs |
| 39 | 11.6.9 Umar evaluation 11.6.9.1 Calculation 11.6.9.2 Plot 11.6.9.3 Lines 11.6.9.4 Assessment 11.7 Test for unbalance reduction ratio, URR 11.7.1 URR tests on single-plane balancing machines 11.7.2 URR tests on two-plane balancing machines 11.7.3 General |
| 42 | 11.7.4 Preparation of test sheets 11.7.4.1 Two-plane test 11.7.4.2 Single-plane test 11.7.5 Plane setting 11.7.6 URR test runs 11.7.6.1 Starting-point |
| 43 | 11.7.6.2 Test planes 11.7.6.3 Procedure 11.7.7 Plotting URR test data 11.7.7.1 Evaluation diagrams 11.7.7.2 Two-plane test 11.7.7.3 Single-plane test |
| 48 | 11.7.8 Evaluation 11.8 Test for couple unbalance interference on single-plane machines 11.8.1 Starting point 11.8.2 Procedure 11.8.3 Evaluation 11.9 Compensator test 11.9.1 Starting-point 11.9.2 Procedure |
| 49 | 11.9.3 Evaluation 11.10 Simplified tests 11.10.1 General 11.10.2 Simplified Umar test 11.10.3 Simplified URR test |
