Standard No.:	GB/T 41850.2-2026
English Name:	Mechanical vibration—Measurement and evaluation of machine vibration—Part 2:Land-based gas turbines,steam turbines and generators in excess of 40 MW,with fluid-film bearings and rated speeds of 1 500 r/min,1 800 r/min,3 000 r/min and 3 600 r/min
Chinese Name:	机械振动 机器振动的测量和评价 第2部分：40 MW以上,使用滑动轴承的，额定转速为1500 r/min、1800 r/min、3000 r/min和3600 r/min陆地安装的燃气轮机、汽轮机和发电机
Chinese Classification:	J04    Basic standards and general methods
Professional Classification:	GB    National Standard
ICS Classification:	17.16 17.16    Vibrations, shock and vibration measurements 17.16
Source Content Issued by:	SAMR, SAC
Issued on:	2026-7-30
Implemented on:	2027-2-1
Status:	to be valid
Superseding:	GB/T 6075.2-2012 Mechanical vibration—Evaluation of machine vibration by measurements on non-rotating parts—Part 2:Land-based steam turbines and generators in excess of 50 MW with normal operating speeds of 1 500 r/min 1 800 r/min 3 000 r/min and 3 600 r/min GB/T 11348.2-2012 Mechanical vibration—Evaluation of machines vibration by measurements on rotating shafts—Part 2:Land-based steam turbine-generators in excess of 50 MW with normal operating speeds of 1 500 r/min,1 800 r/min,3 000 r/min and 3 600 r/min
Target Language:	English
File Format:	PDF
Word Count:	12500 words
Translation Price(USD):	375.0
Delivery:	via email in 1~3 business day

GB/T 41850.2-2026 Mechanical vibration—Measurement and evaluation of machine vibration—Part 2:Land-based gas turbines,steam turbines and generators in excess of 40 MW,with fluid-film bearings and rated speeds of 1 500 r/min,1 800 r/min,3 000 r/min and 3 600 r/min 1 Scope This document is applicable to land-based gas turbines, steam turbines and generators (whether coupled with gas and/or steam turbines) with power outputs greater than 40 MW, fluid-film bearings and rated speeds of 1500 r/min, 1800 r/min, 3000 r/min or 3600 r/min. The criteria provided in this document can be applied to the vibration of the gas turbine, steam turbine and generator (including synchronizing clutches). This document establishes provisions for valuating the severity of the following in-situ, broad-band vibration: a) structural vibration at all main bearing housings or pedestals measured radial (i.e. transverse) to the shaft axis; b) structural vibration at thrust bearing housings measured in the axial direction; c) vibration of rotating shafts radial (i.e. transverse) to the shaft axis at, or close to, the main bearings. These are in terms of the following: — vibration under normal steady-state operating conditions; — vibration during other (non-steady-state) conditions when transient changes are taking place, including run up or run down, initial loading and load changes; — changes in vibration which can occur during normal steady-state operation. This document is not applicable to the following: i) electromagnetic excited vibration with twice line frequency at the generator stator windings, core and housing; ii) aero-derivative gas turbines (including gas turbines with dynamic properties similar to those of aero-derivatives); Note: ISO 3977-3 defines aero-derivatives as aircraft propulsion gas generators adapted to drive mechanical, electrical or marine propulsion equipment. Large differences exist between heavy-duty and aero-derivative gas turbines, for example, in casing flexibility, bearing design, rotor-to-stator mass ratio and mounting structure. Different criteria, therefore, apply for these two turbine types. iii) steam turbines and/or generators with outputs less than or equal to 40 MW or with rated speeds other than 1500 r/min, 1800 r/min, 3000 r/min or 3600 r/min (although generators seldom fall into this latter category) (see ISO 7919-3 and ISO 10816-3); iv) gas turbines with outputs less than or equal to 40 MW or with rated speeds other than 1500 r/min, 1800 r/min, 3000 r/min or 3600 r/min (see ISO 7919-3 or ISO 7919-4 and ISO 10816-3 or ISO 10816-4); v) the evaluation of combustion vibration but does not preclude monitoring of combustion vibration. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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. ISO 20816-1:2016 Mechanical vibration — Measurement and evaluation of machine vibration — Part 1: General guidelines Note: GB/T 41850.1-2024 Mechanical vibration—Measurement and evaluation of machine vibration—Part 1: General guidelines (ISO 20816-1:2016) 3 Terms and definitions No terms and definitions are listed in this document. 4 Measurement procedures 4.1 General The measurement procedures and instrumentation shall comply with the general requirements given in ISO 20816-1. ISO 20816-1, as well as this document, cover vibration of non-rotating parts and rotating shafts. However, this does not mean that both sets of measurements shall be taken on any particular machine. In the past, it was common practice for some users and manufacturers to use measurements only of non-rotating parts or only of rotating shafts or a combination of both. More recently, it has become more common to use a combination of both types of measurement but this is not mandatory. The choice of whether to measure vibration of non-rotating parts, rotating shafts or a combination of both is dependent on the particular application and shall always be agreed between the machine supplier and purchaser prior to installation. The characteristics of the measurement system should be known with regard to the effects of the environment. Care should be taken to ensure that the measurement equipment is not unduly influenced by external sources, including: a) temperature variations; b) electromagnetic fields; c) airborne and structure-borne noise, e.g. from neighbouring machines; d) transducer power source variations; e) combustion vibration; f) cable impedance; g) transducer cable length; h) transducer orientation; i) structural characteristics of the transducer attachment. In special cases where significant low-frequency vibration can be transmitted to the machine, such as in earthquake regions, it can be necessary to filter the low-frequency response of the instrumentation.

Foreword Introduction 1 Scope 2 Normative references 3 Terms and definitions 4 Measurement procedures 4.1 General 4.2 Measurements of vibration of non-rotating parts 4.3 Measurements of vibration of rotating shafts 5 Evaluation criteria 5.1 General 5.2 Criterion I: Vibration magnitude 5.3 Criterion II: Change in vibration magnitude under steady-state conditions at rated speed 5.4 Supplementary procedures/criteria 5.5 Evaluation based on vibration vector information Annex A (normative) Evaluation zone boundaries for vibration of non-rotating parts Annex B (normative) Evaluation zone boundaries for vibration of rotating shafts Annex C (informative) Example of setting ALARM and TRIP values Annex D (informative) Cautionary notes about the use of vibration velocity criteria at low rotational speeds Annex E (informative) Evaluation zone boundary limits and bearing clearance Bibliography