GB/T 12350-2022Safety requirements of small power motors (English PDF)

1 Scope

GB/T 12350-2022 is the Chinese national standard on safety requirements of small power motors, in the field of electrical engineering. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 15 April 2022 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 November 2022. Classification: ICS 29.160.30, CCS K20. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document specifies the general safety requirements of small power motors. This document applies to small power motors (hereinafter referred to as the motors) specified in GB/T 5171.1; it also applies as a reference to the implementation of other similar motors.

2 Normative references

The following documents are normatively referenced in this document and are indispensable for its application. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB/T 755, Rotating electrical machines - Rating and performance

GB/T 1971, Rotating electrical machines - Terminal markings and direction of rotation

GB/T 2423.3, Environmental testing - Part

3 Terms and definitions

Terms and definitions determined by GB/T 2900.25, GB/T 2900.27, GB 4706.1 and GB/T 5171.1, as well as the following, are applicable to this document.

3.1 Creepage distance The shortest path distance along the surface of insulating material between two conductive parts, or between a conductive part and an accessible surface.

3.2 Clearance The shortest spatial distance between two conductive parts, or between a conductive part and an accessible surface.

3.3 Enclosure Easy-to-reach motor surfaces, including the surfaces of motor junction box and other parts. Excluding hard-to-reach parts.

3.4 Component Special accessories for motors. Examples. centrifugal switch, capacitor, thermal protector, etc.

3.5 Insulator A component used to insulate and support conductors.

3.6 Diameter of motor Diameter measured on the circumscribed circle of the motor stator casing, excluding the dimensions of the motor's radiation ribs, junction boxes and welds.

3.7 Pollution degree Expected degree of contamination of the microenvironment, represented by numbers.

Note. Pollution degree 1.non-pollution, or only dry, non-conductive pollution, which is of no effect. Pollution degree 2.only non-conductive pollution in general; but occasional short-lived conductive pollution by must-be-expected condensation. Pollution degree 3.conductive pollution; or conductive pollution changed from dry non-conductive pollution due to expected condensation. Pollution degree 4.persistent conductive pollution, for example, caused by conductive dust or rain or snow.

3.8 Basic insulation Insulation applied to live parts to provide basic protection against electric shock.

3.9 Supplementary insulation Separate insulation additionally applied to basic insulation in order to provide protection against electric shock in the event of failure of the basic insulation.

4 Marking and description

4.1 Each motor shall have a firm nameplate indicating the rated data and other necessary matters of the motor in its obvious position. The nameplate of the motor shall contain the following.

a) name of the motor;

b) motor model or specification;

c) rated voltage or rated voltage range (unit. V);

d) rated frequency (unit. Hz);

e) symbols of the nature of power supply, except those marked with the rated frequency;

f) rated current (Unit. A);

g) rated output power or rated output power range (unit. W or kW); the motor with rated torque is only marked with rated output torque or rated output torque range. -- For motors that are completely fitted with other equipment and devices and cannot be separated separately, such as vacuum cleaner motors and drainage pump motors, it is allowed to mark the input power; it shall be indicated on the nameplate that the power is input power; -- The rated output power range or rated output torque range is only applicable to motors with stepless speed regulation; -- For motors with step speed regulation function, rated output power or rated output torque shall be marked in grades;

h) rated speed or rated speed range (unit. r/min);

Note. The rated speed range is only applicable to motors with stepless speed regulation.

i) efficiency (for motors with energy efficiency labelling requirements);

j) working system (if not S1 working system);

k) capacitance and rated voltage of the capacitor (where applicable);

l) wiring diagram (if there is a wiring diagram label in other positions such as the casing or the manual, it is not necessary to indicate it);

5 Base and enclosure

5.1 General The motor shall have sufficient mechanical strength and rigidity to avoid safety accidents such as fire and electric shock caused by the reduction of clearance or creepage distance, loose parts or displacement caused by mechanical deformation.

6 Mechanical assemblies and parts

6.1 The motor assembly shall be firm and reliable to prevent harmful effects from vibration during normal operation. The rotating parts of the motor shall be able to withstand the overspeed test specified in GB/T 5171.1 without loosening and harmful deformation.

6.2 If the motor has a junction box for accommodating and connecting the power supply wires, the junction box shall be solid and durable, and its installation shall be firm, and no harmful deformation and loosening are allowed. Compliance with the requirements shall be determined by inspection and by the following tests. For a motor whose base number is H90 or above or diameter is greater than 180 mm, when the motor is installed in any predetermined position, the junction box shall be able to withstand a static load of 110 kg on its horizontal plane without being damaged. For a motor whose base number is H90 and below or diameter is 180 mm and below, when the motor is installed in any predetermined position, the static load on the horizontal plane of the junction box shall be calculated as

1.42 kg/cm2 on the horizontal plane, but shall not be larger than 110 kg. This load can be applied through a metal plane with a diameter of 50 mm without being damaged. If the junction box is shifted or deformed after the load test is carried out, and the clearance and creepage distance between the box body and any terminal still meet the requirements of Chapter 15, the junction box is considered to be qualified.

6.3 If the motor is equipped with a lifting ring or similar lifting device for hoisting the motor, its strength limit is the base, and its safety factor is at least 5.

6.4 For a motor with a junction box, the junction box shall be installed in a position that is easy to inspect during normal use of the motor, and shall be installed firmly and not allowed to loosen.

6.5 If the motor has capacitors, switches or similar devices, they shall be installed firmly, not allowed to loosen, and shall be easy to replace.

6.6 The motor shall have a certain moisture-proof ability. The motor insulation structures, such as enameled wire, slot insulation, binding tape (rope), slot wedge, shall be provided with certain moisture-proof measures, and shall have good molding and assembly to ensure that the motor windings have reliable insulation and mechanical properties.

7 Anti-corrosion

If the corrosion of steel parts may lead to motor fire, electric shock or personal injury, these parts shall be painted, coated, electroplated or treated with other measures to ensure sufficient rust resistance. However, for steel and iron parts in the enclosure, if the oxidation is not obvious when exposed to the air, parts such as bearings and punching pieces may not require anti-corrosion. For parts whose anti-rust ability is doubtful, the following tests shall also be carried out to check and judge.

9 Connecting pieces

9.1 The connecting pieces, such as screws, used for electrical or other connection in the motor shall be able to withstand the mechanical stress generated in normal use. Parts such as screws and nuts shall not be made of soft or creep-prone metals such as zinc and aluminum.

9.2 The screws that may be turned by the user shall have a certain length to ensure a reliable connection.

9.3 For screws used for mechanical connection between different parts, if the connecting piece is current-carrying, the screw shall be securely locked to prevent loosening.

10 Internal wiring

10.1 The internal wiring of the motor refers to the internal wiring except the windings. They shall be fixed firmly and not allowed to be loose. Two or more wires in the same direction shall be bundled together. The wires shall not be placed on parts with acute angles and sharp edges, and shall be effectively prevented from contacting with moving parts.

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