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Position: Chinese Standard in English/GB/T 3785.1-2023
GB/T 3785.1-2023   Electroacoustics—Sound level meters—Part 1: Specifications (English Version)
Standard No.: GB/T 3785.1-2023 Status:valid remind me the status change

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Language:English File Format:PDF
Word Count: 23000 words Price(USD):690.0 remind me the price change

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Implemented on:2023-12-1 Delivery: via email in 1~3 business day
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Standard No.: GB/T 3785.1-2023
English Name: Electroacoustics—Sound level meters—Part 1: Specifications
Chinese Name: 电声学 声级计 第1部分:规范
Chinese Classification: A59    Acoustic Measurement
Professional Classification: GB    National Standard
ICS Classification: 17.140.50 17.140.50    Electroacoustics 17.140.50
Issued by: SAMR; SAC
Issued on: 2023-05-23
Implemented on: 2023-12-1
Status: valid
Superseding:GB/T 3785.1-2010 Electroacoustics—Sound level meters—Part 1:Specifications
Language: English
File Format: PDF
Word Count: 23000 words
Price(USD): 690.0
Delivery: via email in 1~3 business day
GB/T 3785.1-2023 Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance 1 Scope This document specifies methods for determining machine vibration sensitivity to unbalance and provides evaluation guidelines as a function of the proximity of relevant resonance rotational speeds to the operating speed. This document is only concerned with once-per-revolution vibration caused by unbalance. It also makes recommendations on how to apply the numerical sensitivity values in some particular cases. It includes a classification system that can be applied to machines which is related to their susceptibility to a change in unbalance. Machines are classified into three types of susceptibility and five ranges of sensitivity. The sensitivity values are intended for use on simple machine systems, preferably with rotors having only one resonance speed over their entire operating speed range. The sensitivity values can also be used for machines that have more resonance speeds in their operating speed range if the resonance speeds are widely separated (e.g. by more than 20 %). The sensitivity values given are not intended to serve as acceptance specifications for any machine group, but rather to give indications regarding how to avoid gross deficiencies as well as specifying exaggerated or unattainable requirements. They can also serve as a basis for more involved investigations (e.g. when in special cases a more exact determination of the required sensitivity is necessary). If due regard is paid to the values given, satisfactory running conditions can be expected in most cases. The consideration of the sensitivity values alone does not guarantee that a given magnitude of vibration in operating is not exceeded. Many other sources of vibration can occur which lie outside the scope of this document. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 21940-2 Mechanical vibration - Rotor balancing - Part 2: Vocabulary Note: GB/T 6444-2008, Mechanical vibration - Balancing - Vocabulary (ISO 1925:2001, IDT) 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 21940-2 apply. Note: Some of the terms used are explained in Annex A. 4 Machine susceptibility classification 4.1 General Machine susceptibility classification is based on the likelihood of a machine experiencing significant unbalance during operation. Machines with low susceptibility are allowed higher sensitivity values (require less damping), and machines with high susceptibility are restricted to lower sensitivity values (require more damping). 4.2 Type I: Low susceptibility Machines of this type have a low likelihood of experiencing significant unbalance changes during operation. Typically they have a large rotor mass in comparison to their support housing and operate in a clean environment, have negligible wear and exhibit minimal rotor distortion caused by temperature change. Examples: Paper machine rolls, printing rolls, and high-speed vacuum pumps. 4.3 Type II: Moderate susceptibility Machines of this type have a moderate likelihood of experiencing significant unbalance changes during operation. Typically they are machines which operate in environments with large temperature changes or experience moderate wear. Examples: Pumps in clean media, electric armatures, gas and steam turbines, generators, and turbo compressors. 4.4 Type III: High susceptibility Machines of this type have a high likelihood of experiencing significant unbalance changes during operation. Typically they are machines which run in deposit producing (e.g. pumps operating in sludge) or corrosive environments. Examples: Centrifuges, fans, screw conveyors, and hammer mills. 4.5 Machine susceptibility correction factors The remainder of this part of ISO 21940 focuses on moderate susceptibility classification machines (type II). For evaluation of low susceptibility or high susceptibility machines, a correction factor can be applied to adjust the sensitivity range. Table 1 shows correction factors that are applied to the sensitivity values (see Clause 5) based on machine susceptibility type (see 4.2 to 4.4).
GB/T 3785.1-2023 is referred in:
*GB/T 44038-2024 Requirements and testing methods of warning sound for vehicle reversing
*GB/T 44040-2024 Measurement methods for noise emitted by heavy-duty vehicles in multiple driving mode conditions
*GB/T 25982-2024 Limits and measurement methods for bus interior noise
Code of China
Standard
GB/T 3785.1-2023  Electroacoustics—Sound level meters—Part 1: Specifications (English Version)
Standard No.GB/T 3785.1-2023
Statusvalid
LanguageEnglish
File FormatPDF
Word Count23000 words
Price(USD)690.0
Implemented on2023-12-1
Deliveryvia email in 1~3 business day
Detail of GB/T 3785.1-2023
Standard No.
GB/T 3785.1-2023
English Name
Electroacoustics—Sound level meters—Part 1: Specifications
Chinese Name
电声学 声级计 第1部分:规范
Chinese Classification
A59
Professional Classification
GB
ICS Classification
Issued by
SAMR; SAC
Issued on
2023-05-23
Implemented on
2023-12-1
Status
valid
Superseded by
Superseded on
Abolished on
Superseding
GB/T 3785.1-2010 Electroacoustics—Sound level meters—Part 1:Specifications
Language
English
File Format
PDF
Word Count
23000 words
Price(USD)
690.0
Keywords
GB/T 3785.1-2023, GB 3785.1-2023, GBT 3785.1-2023, GB/T3785.1-2023, GB/T 3785.1, GB/T3785.1, GB3785.1-2023, GB 3785.1, GB3785.1, GBT3785.1-2023, GBT 3785.1, GBT3785.1
Introduction of GB/T 3785.1-2023
GB/T 3785.1-2023 Mechanical vibration - Rotor balancing - Part 31: Susceptibility and sensitivity of machines to unbalance 1 Scope This document specifies methods for determining machine vibration sensitivity to unbalance and provides evaluation guidelines as a function of the proximity of relevant resonance rotational speeds to the operating speed. This document is only concerned with once-per-revolution vibration caused by unbalance. It also makes recommendations on how to apply the numerical sensitivity values in some particular cases. It includes a classification system that can be applied to machines which is related to their susceptibility to a change in unbalance. Machines are classified into three types of susceptibility and five ranges of sensitivity. The sensitivity values are intended for use on simple machine systems, preferably with rotors having only one resonance speed over their entire operating speed range. The sensitivity values can also be used for machines that have more resonance speeds in their operating speed range if the resonance speeds are widely separated (e.g. by more than 20 %). The sensitivity values given are not intended to serve as acceptance specifications for any machine group, but rather to give indications regarding how to avoid gross deficiencies as well as specifying exaggerated or unattainable requirements. They can also serve as a basis for more involved investigations (e.g. when in special cases a more exact determination of the required sensitivity is necessary). If due regard is paid to the values given, satisfactory running conditions can be expected in most cases. The consideration of the sensitivity values alone does not guarantee that a given magnitude of vibration in operating is not exceeded. Many other sources of vibration can occur which lie outside the scope of this document. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 21940-2 Mechanical vibration - Rotor balancing - Part 2: Vocabulary Note: GB/T 6444-2008, Mechanical vibration - Balancing - Vocabulary (ISO 1925:2001, IDT) 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 21940-2 apply. Note: Some of the terms used are explained in Annex A. 4 Machine susceptibility classification 4.1 General Machine susceptibility classification is based on the likelihood of a machine experiencing significant unbalance during operation. Machines with low susceptibility are allowed higher sensitivity values (require less damping), and machines with high susceptibility are restricted to lower sensitivity values (require more damping). 4.2 Type I: Low susceptibility Machines of this type have a low likelihood of experiencing significant unbalance changes during operation. Typically they have a large rotor mass in comparison to their support housing and operate in a clean environment, have negligible wear and exhibit minimal rotor distortion caused by temperature change. Examples: Paper machine rolls, printing rolls, and high-speed vacuum pumps. 4.3 Type II: Moderate susceptibility Machines of this type have a moderate likelihood of experiencing significant unbalance changes during operation. Typically they are machines which operate in environments with large temperature changes or experience moderate wear. Examples: Pumps in clean media, electric armatures, gas and steam turbines, generators, and turbo compressors. 4.4 Type III: High susceptibility Machines of this type have a high likelihood of experiencing significant unbalance changes during operation. Typically they are machines which run in deposit producing (e.g. pumps operating in sludge) or corrosive environments. Examples: Centrifuges, fans, screw conveyors, and hammer mills. 4.5 Machine susceptibility correction factors The remainder of this part of ISO 21940 focuses on moderate susceptibility classification machines (type II). For evaluation of low susceptibility or high susceptibility machines, a correction factor can be applied to adjust the sensitivity range. Table 1 shows correction factors that are applied to the sensitivity values (see Clause 5) based on machine susceptibility type (see 4.2 to 4.4).
Contents of GB/T 3785.1-2023
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Keywords:
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