GB/T 14711-2025 General requirements for safety of small and medium size rotating electrical machines English
1 Scope
This document specifies general safety requirements for the small- and medium-sized rotating electrical machines, i.e., electric motors and generators (hereinafter referred to as “electrical machines”), subject to GB/T 755.
This document applies to activities related to small- and medium-sized rotating electrical machines, such as design, manufacture, inspection and operation. This document may also apply to other electrical machines as a reference.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions 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.
GB/T 755 Rotating electrical machines - Rating and performance
GB/T 825 Eyebolts
GB/T 1971 Rotating electrical machines - Terminal markings and direction of rotation
GB/T 2423.3 Environmental testing - Part 2: Testing method - Test Cab: Damp heat, steady state
GB/T 2423.4 Environmental testing for electric and electronic products - Part 2: Test methods - Test Db: Damp heat, cyclic (12 h+12 h cycle)
GB/T 2900.1-2008 Electrotechnical terminology - Fundamental terms
GB/T 2900.18-2008 Electrotechnical terminology - Low voltage apparatus
GB/T 2900.25 Electrotechnical terminology - Rotating electrical machines
GB/T 4074.7-2024 Test methods of winding wires - Part 7: Test procedure for the determination of the temperature index of enameled winding wires
GB/T 4207 Method for the determination of the proof and the comparative tracking indices of solid insulating materials
GB/T 4208 Degrees of protection provided by enclosure (IP code)
GB/T 4942 Degrees of protection provided by the integral design of rotating electrical machines (IP code) - Classification
GB/T 5169.11 Fire hazard testing for electric and electronic products - Part 11: Glowing/hot-wire based test methods - Glow-wire flammability test method for end-products (GWEPT)
GB/T 5169.12 Fire hazard testing for electric and electronic products - Part 12: Glowing/hot-wire based test methods - Glow-wire flammability index (GWFI) test method for materials
GB/T 5169.16 Fire hazard testing for electric and electronic products - Part 16: Test flames - 50 W horizontal and vertical flame test methods
GB/T 5169.21 Fire hazard testing for electric and electronic products - Part 21: Abnormal heat - Ball pressure test method
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 11026.4-2012 Electrical insulating materials - Thermal endurance properties - Part 4: Ageing ovens - Single-chamber ovens
GB/T 12113-2023 Methods of measurement of touch current and protective conductor current
GB/T 12665 Requirements of damp-heat testing of electrical machine for service in general environmental condition
GB/T 13002 Rotating electrical machines - Thermal protection
GB/T 16422.2 Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps
GB/T 17948.1-2018 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 17948.2 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 17948.3 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for form-wound windings - Thermal evaluation and classification of insulation systems used in rotating machines
GB/T 17948.4 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 20111.3 Electrical insulation systems - Procedures for thermal evaluation - Part 3: Specific requirements for encapsulated-coil model - Wire-wound electrical insulation system (EIS)
GB/T 20139.1-2016 Electrical insulation systems - Thermal evaluation of modifications to an established electrical insulation system (EIS) - Part 1: Wire-wound winding EIS
GB/T 20139.2-2017 Electrical insulation systems - Thermal evaluation of modifications to an established electrical insulation system (EIS) - Part 2: Form-wound EIS
GB/T 21707 Insulation specification for variable frequency adjustable speed definite purpose converter-fed three-phase induction motors
GB/T 22714 Test specifications of interturn insulation of form-wound winding for AC low-voltage electrical machines
GB/T 22716 Test specifications of interturn insulation of armature winding for DC electrical machines
GB/T 22718 Thermal evaluation methods of insulation systems for high-voltage electrical machines
GB/T 22719.1 Interturn insulation of random-wound winding for AC low-voltage electrical machines - Part 1: Test methods
GB/T 22719.2 Interturn insulation of random-wound winding for AC low-voltage electrical machines - Part 2: Test limits
GB/T 22720.1-2017 Rotating electrical machines - Qualification and quality control tests of partial discharge free electrical insulation systems (Type Ⅰ) used in rotating electrical machines fed from voltage converters
GB/T 22720.2-2019 Rotating electrical machines - Qualification tests for the partial discharge resistant electrical insulation systems (Type Ⅱ) used in rotating electrical machines fed from voltage converters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 755, GB/T 2900.1-2008, GB/T 2900.18-2008, GB/T 2900.25 and the following apply.
3.1
clearance
shortest distance in space between two electrically conductive parts, or between an electrically conductive part and a readily accessible surface of an electrical machine
[Source: GB/T 2900.18-2008, 6.1.1, modified]
3.2
creepage distance
shortest path along the surface of an insulating material between two electrically conductive parts, or between an electrically conductive part and a readily accessible surface of an electrical machine
[Source: GB/T 2900.18-2008, 3.3.164, modified]
3.3
standby generator
stationary generator intended to provide emergency power and capable of supporting rated loads in continuous operation
3.4
leads
connecting wires that connect winding coils to terminals, and to other coils, or lead coils to other conductors within the electrical machine
Note: In exceptional cases, they may be extended to the outside of the electrical machine.
3.5
flexible supply cord
flexible cord for supplying power, directly introduced from inside to outside of the electrical machine
3.6
touch current
electric current passing through a human body or through livestock when it touches one or more accessible parts of an installation or of equipment
[Source: GB/T 12113-2003, 3.1].
3.7
frequency converter
electrical energy converter that changes the frequency (excluding the zero frequency) associated with electrical energy
[Source: GB/T 2900.1-2008, 3.3.96]
3.8
inverter
electrical energy converter that converts direct current into single-phase or multi-phase alternating current
[Source: GB/T 2900.1-2008, 3.3.99]
3.9
thermal class
value of the maximum continuous use temperature (in degrees Celsius) corresponding to the insulation structure
[Source: GB/T 11021-2014, 3.11].
3.10
type Ⅰ insulation system
insulation structure which is not subjected to partial discharge in its life cycle
[Source: GB/T 21707-2018, 3.2].
3.11
type Ⅱ insulation system
insulation structure which is subjected to partial discharge in its life
Note: Generally, type II insulation systems are adopted for electrical machines with a rated voltage greater than or equal to 700 V.
[Source: GB/T 21707-2018, 3.3, modified]
3.12
impulse voltage insulation class for type Ⅰ insulation systems
safe peak-to-peak voltage assigned by the manufacturer in relation to the rated voltage for an electrical machine powered by a specified frequency converter/inverter, and indicated in its documentation and on its rating plate
[Source: GB/T 22720.1-2017, 3.19].
3.13
impulse voltage insulation class for type Ⅱ insulation systems
peak-to-peak voltage class 1, 2, 3, 4, 5, 6, 7 and S with reliable operation, including certain time parameters
Note: It is assigned by the manufacturer of the machine in relation to the rated voltage for a specified frequency converter-driven electrical machine, and indicated in its documentation and on its rating plate, if applicable.
[Source: GB/T 22720.1-2019, 3.18, modified]
3.14
small power motor
motor with the maximum continuous rating not exceeding 1.1 kW when converted to 1,500 r/min
[Source: GB/T 2900.18-2008, 411-33-34]
3.15
service factor
factor indicating the permissible load that can be supported continuously at the rated voltage and frequency
Note 1: The load corresponds to the rated power in the case of AC motor, the rated armature current in the case of DC machine, or the rated output (power) in the case of generator.
Note 2: For a synchronous motor with a power factor of 1, the rated power factor is maintained; for a synchronous motor with a leading power factor, constant excitation is maintained.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Marking and instructions
5 Frame and enclosure
6 Junction box and wiring device
7 Conduit bushings and equivalent threaded openings
8 Mechanical assembly
9 Earthing
10 Flexible supply cord
11 Clearance and creepage distance
12 Internal wiring
13 Connectors
14 Electrical insulation
15 Insulation structure
16 Electric brush holder and terminals
17 Wiring terminals
18 Non-metallic functional components
19 Rating test
20 Thermal test
21 Touch current
22 Insulation resistance
23 Dielectric strength test
24 Mechanical strength test
25 Protection test
26 Damp heat test
27 Corrosion resistance
28 Components
29 Electromagnetic compatibility (EMC)
Bibliography
GB/T 14711-2025 General requirements for safety of small and medium size rotating electrical machines English
1 Scope
This document specifies general safety requirements for the small- and medium-sized rotating electrical machines, i.e., electric motors and generators (hereinafter referred to as “electrical machines”), subject to GB/T 755.
This document applies to activities related to small- and medium-sized rotating electrical machines, such as design, manufacture, inspection and operation. This document may also apply to other electrical machines as a reference.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions 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.
GB/T 755 Rotating electrical machines - Rating and performance
GB/T 825 Eyebolts
GB/T 1971 Rotating electrical machines - Terminal markings and direction of rotation
GB/T 2423.3 Environmental testing - Part 2: Testing method - Test Cab: Damp heat, steady state
GB/T 2423.4 Environmental testing for electric and electronic products - Part 2: Test methods - Test Db: Damp heat, cyclic (12 h+12 h cycle)
GB/T 2900.1-2008 Electrotechnical terminology - Fundamental terms
GB/T 2900.18-2008 Electrotechnical terminology - Low voltage apparatus
GB/T 2900.25 Electrotechnical terminology - Rotating electrical machines
GB/T 4074.7-2024 Test methods of winding wires - Part 7: Test procedure for the determination of the temperature index of enameled winding wires
GB/T 4207 Method for the determination of the proof and the comparative tracking indices of solid insulating materials
GB/T 4208 Degrees of protection provided by enclosure (IP code)
GB/T 4942 Degrees of protection provided by the integral design of rotating electrical machines (IP code) - Classification
GB/T 5169.11 Fire hazard testing for electric and electronic products - Part 11: Glowing/hot-wire based test methods - Glow-wire flammability test method for end-products (GWEPT)
GB/T 5169.12 Fire hazard testing for electric and electronic products - Part 12: Glowing/hot-wire based test methods - Glow-wire flammability index (GWFI) test method for materials
GB/T 5169.16 Fire hazard testing for electric and electronic products - Part 16: Test flames - 50 W horizontal and vertical flame test methods
GB/T 5169.21 Fire hazard testing for electric and electronic products - Part 21: Abnormal heat - Ball pressure test method
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 11026.4-2012 Electrical insulating materials - Thermal endurance properties - Part 4: Ageing ovens - Single-chamber ovens
GB/T 12113-2023 Methods of measurement of touch current and protective conductor current
GB/T 12665 Requirements of damp-heat testing of electrical machine for service in general environmental condition
GB/T 13002 Rotating electrical machines - Thermal protection
GB/T 16422.2 Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps
GB/T 17948.1-2018 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 17948.2 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 17948.3 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for form-wound windings - Thermal evaluation and classification of insulation systems used in rotating machines
GB/T 17948.4 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification
GB/T 20111.3 Electrical insulation systems - Procedures for thermal evaluation - Part 3: Specific requirements for encapsulated-coil model - Wire-wound electrical insulation system (EIS)
GB/T 20139.1-2016 Electrical insulation systems - Thermal evaluation of modifications to an established electrical insulation system (EIS) - Part 1: Wire-wound winding EIS
GB/T 20139.2-2017 Electrical insulation systems - Thermal evaluation of modifications to an established electrical insulation system (EIS) - Part 2: Form-wound EIS
GB/T 21707 Insulation specification for variable frequency adjustable speed definite purpose converter-fed three-phase induction motors
GB/T 22714 Test specifications of interturn insulation of form-wound winding for AC low-voltage electrical machines
GB/T 22716 Test specifications of interturn insulation of armature winding for DC electrical machines
GB/T 22718 Thermal evaluation methods of insulation systems for high-voltage electrical machines
GB/T 22719.1 Interturn insulation of random-wound winding for AC low-voltage electrical machines - Part 1: Test methods
GB/T 22719.2 Interturn insulation of random-wound winding for AC low-voltage electrical machines - Part 2: Test limits
GB/T 22720.1-2017 Rotating electrical machines - Qualification and quality control tests of partial discharge free electrical insulation systems (Type Ⅰ) used in rotating electrical machines fed from voltage converters
GB/T 22720.2-2019 Rotating electrical machines - Qualification tests for the partial discharge resistant electrical insulation systems (Type Ⅱ) used in rotating electrical machines fed from voltage converters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 755, GB/T 2900.1-2008, GB/T 2900.18-2008, GB/T 2900.25 and the following apply.
3.1
clearance
shortest distance in space between two electrically conductive parts, or between an electrically conductive part and a readily accessible surface of an electrical machine
[Source: GB/T 2900.18-2008, 6.1.1, modified]
3.2
creepage distance
shortest path along the surface of an insulating material between two electrically conductive parts, or between an electrically conductive part and a readily accessible surface of an electrical machine
[Source: GB/T 2900.18-2008, 3.3.164, modified]
3.3
standby generator
stationary generator intended to provide emergency power and capable of supporting rated loads in continuous operation
3.4
leads
connecting wires that connect winding coils to terminals, and to other coils, or lead coils to other conductors within the electrical machine
Note: In exceptional cases, they may be extended to the outside of the electrical machine.
3.5
flexible supply cord
flexible cord for supplying power, directly introduced from inside to outside of the electrical machine
3.6
touch current
electric current passing through a human body or through livestock when it touches one or more accessible parts of an installation or of equipment
[Source: GB/T 12113-2003, 3.1].
3.7
frequency converter
electrical energy converter that changes the frequency (excluding the zero frequency) associated with electrical energy
[Source: GB/T 2900.1-2008, 3.3.96]
3.8
inverter
electrical energy converter that converts direct current into single-phase or multi-phase alternating current
[Source: GB/T 2900.1-2008, 3.3.99]
3.9
thermal class
value of the maximum continuous use temperature (in degrees Celsius) corresponding to the insulation structure
[Source: GB/T 11021-2014, 3.11].
3.10
type Ⅰ insulation system
insulation structure which is not subjected to partial discharge in its life cycle
[Source: GB/T 21707-2018, 3.2].
3.11
type Ⅱ insulation system
insulation structure which is subjected to partial discharge in its life
Note: Generally, type II insulation systems are adopted for electrical machines with a rated voltage greater than or equal to 700 V.
[Source: GB/T 21707-2018, 3.3, modified]
3.12
impulse voltage insulation class for type Ⅰ insulation systems
safe peak-to-peak voltage assigned by the manufacturer in relation to the rated voltage for an electrical machine powered by a specified frequency converter/inverter, and indicated in its documentation and on its rating plate
[Source: GB/T 22720.1-2017, 3.19].
3.13
impulse voltage insulation class for type Ⅱ insulation systems
peak-to-peak voltage class 1, 2, 3, 4, 5, 6, 7 and S with reliable operation, including certain time parameters
Note: It is assigned by the manufacturer of the machine in relation to the rated voltage for a specified frequency converter-driven electrical machine, and indicated in its documentation and on its rating plate, if applicable.
[Source: GB/T 22720.1-2019, 3.18, modified]
3.14
small power motor
motor with the maximum continuous rating not exceeding 1.1 kW when converted to 1,500 r/min
[Source: GB/T 2900.18-2008, 411-33-34]
3.15
service factor
factor indicating the permissible load that can be supported continuously at the rated voltage and frequency
Note 1: The load corresponds to the rated power in the case of AC motor, the rated armature current in the case of DC machine, or the rated output (power) in the case of generator.
Note 2: For a synchronous motor with a power factor of 1, the rated power factor is maintained; for a synchronous motor with a leading power factor, constant excitation is maintained.
Contents of GB/T 14711-2025
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Marking and instructions
5 Frame and enclosure
6 Junction box and wiring device
7 Conduit bushings and equivalent threaded openings
8 Mechanical assembly
9 Earthing
10 Flexible supply cord
11 Clearance and creepage distance
12 Internal wiring
13 Connectors
14 Electrical insulation
15 Insulation structure
16 Electric brush holder and terminals
17 Wiring terminals
18 Non-metallic functional components
19 Rating test
20 Thermal test
21 Touch current
22 Insulation resistance
23 Dielectric strength test
24 Mechanical strength test
25 Protection test
26 Damp heat test
27 Corrosion resistance
28 Components
29 Electromagnetic compatibility (EMC)
Bibliography
