GB/T 1971-2021

Rotating electrical machines—Terminal markings and direction of rotation (English Version)

Standard No.

GB/T 1971-2021

Language

Chinese, Available in English version

Release Date

2021

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB/T 1971-2021

Replace

GB/T 1971-2006

Scope

This document is applicable to AC motors and DC motors, and specifically stipulates: a) Marking rules for winding connection points; b) Winding wire end marks; c) Rotation direction; d) Relationship between wire end marks and rotation direction; e) Auxiliary devices The terminal mark of the wire; f) The common wiring diagram of the motor. This document does not apply to turbine-type synchronous motors.

Introduction

Interpretation of the core content of the standard

GB/T1971-2021 is a basic standard in the field of rotating electrical machines. It is equivalent to the IEC60034-8:2014 international standard, which systematically regulates the marking rules for motor winding ends and the method for determining the direction of rotation. This standard applies to all AC/DC rotating electrical machines except turbine-type synchronous motors.

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Main Technical Changes

Changed Items	2006 Edition	2021 Edition
Synchronous Motor Windings	Undefined	New clauses for synchronous motor primary windings, excitation windings and permanent magnet motors
Symbol Marking	Armature Winding Symbol X	Unified to A (see Figure 16/24)
Symbol for Shunt Winding	Symbol F	Changed to E (Appendix A Figure A.22-23)

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Detailed explanation of key rules

1. Line end marking system

Three-phase motors use the U/V/W letter sequence to identify the phase sequence, and the digital suffixes follow the following:

• 1-2: The first winding unit start and end
• 3-4: The second winding unit start and end
• Odd-numbered suffixes are preferably used near the power supply end

Example: Three-phase single-winding delta-connected motor only needs to be marked with U1/V1/W1 (see Figure 2)

2. Determination of rotation direction

Unified regulations for the direction of rotation when facing the D end (spindle end):

Motor type	Clockwise condition
Multi-phase motor	The order of the line end mark letters is consistent with the power supply phase sequence
DC motor	L+/L- polarity corresponds to A1/A2 (and F1/F2)
Single-phase motor	Clockwise when U1-Z1/U2-Z2 is connected in parallel

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Typical application scenarios

Multi-speed motor wiring scheme

The standard adds a new variable torque dual-voltage motor wiring diagram (Figure A.11), key parameters:

• 9-terminal design is used when the voltage ratio is 1:3
• Low-speed delta connection requires interchange of 1U-1W terminals
• High-speed star connection requires neutral point shorting

Note: This solution is not suitable for parallel star starting conditions

Special treatment for DC motors

Series-excited motors (Figure A.24) should note:

• Only mark the two terminals A1/A2
• The direction of rotation must be indicated by the arrow on the casing
• Counterclockwise rotation requires internal adjustment of D1/D2 connection

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Implementation suggestions

1. For permanent magnet synchronous motors, the terminal markings should refer to the rules for asynchronous motors
2. The prefix numbers of multi-speed motors must be arranged in ascending order of speed (Article 6.3)
3. The ground terminal must have the exclusive PE mark and other uses are prohibited (Article 6.1.7)
4. Auxiliary devices use the two-letter codes specified in 4.4 (such as CA for capacitors)