GB/T 27743-2025Inspection method for transformer of special equipment (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020 "Directives for standardization - Part

1.Rules for the structure and drafting of standardizing documents". This document supersedes GB/T 27743-2011 "Inspection method for transformer of special equipment". Compared with GB/T 27743-2011, the main technical changes, apart from structural adjustments and editorial modifications, are as follows: - MODIFY the "scope" (see Clause 1 of this document; Clause 1 of the 2011 version); - ADD the requirements for "operating conditions" (see Clause 4 of this document); - MODIFY the requirements for "safety protection inspection" (see

5.2 of this document;

4.2 of the 2011 version); - MODIFY the requirements for "noise inspection" method (see

5.4 of this document;

4.4 of the 2011 version); - MODIFY the requirements for "specific inspection methods for cut-to-length line for transformer lamination" (see

6.1 of this document;

5.1 of the 2011 version); - MODIFY the requirements for "specific inspection methods for slitting line for transformer lamination" (see

6.2 of this document;

5.2 of the 2011 edition); - MODIFY the requirements for "specific inspection methods for vertical winding machines" (see

6.3 of this document;

5.3 of the 2011 edition); - ADD the requirements for "specific inspection methods for horizontal winding machines" (see

6.4 of this document); - ADD the requirements for "specific inspection methods for foil coil winding machines" (see

6.5 of this document); - MODIFY requirements for "specific inspection method for pressure increase vacuum drying plants and vapour phase drying plants" (see

1 Scope

GB/T 27743-2025 is the Chinese national standard covering checking the machines a transformer factory is built around - the winding and coil forming equipment, the core cutting and stacking lines, the drying and vacuum impregnation plant, and the accuracy and performance each has to hold. Issued on 5 October 2025, it has been in force since 1 May 2026, replacing GB/T 27743-2011.

This document describes the operating conditions, general inspection methods, and specific inspection methods for transformer of specific equipment. This document applies to cut-to-length line for transformer lamination, slitting line for transformer lamination, vertical winding machine, horizontal winding machine, foil coil winding machine, pressure increase vacuum drying plant, and vapour phase drying plant used in transformer of specific equipment.

2 Normative references

The following referenced documents are indispensable for the application 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 150.4 Pressure vessels - Part

3 Terms and definitions

For the purpose of this document, the terms and definitions defined in GB/T 150.4, GB/T 2900.39, JB/T 3857, JB/T 9658, JB/T 10918, JB/T 11054, JB/T 11056, JB/T 11146, and JB/T 11147 apply.

4 Operating conditions

The operating conditions for transformer of specific equipment include.

a) altitude not exceeding 1000 m;

b) ambient temperature -10 °C ~ +40 °C;

c) relative humidity of air within the range of 30 % ~ 85 % (at a temperature of 20 °C ± 5 °C);

d) power supply voltage. 220 V (AC)/380 V (AC), and the fluctuation value of the power supply voltage shall not exceed ±10 % of the rated voltage.

5 General inspection methods

5.1 Operating condition inspection Before the no-load operation performance test, the operating environment and voltage fluctuation of the equipment shall be inspected. Inspection tools include thermometers, hygrometers, voltmeters, etc.