IEC TS 63263:2025

Winding wires - Test methods - Electrical endurance under high frequency voltage impulses

IEC TS 63263:2025 describes a test method for evaluating the lifetime of winding wires under electrical high frequency voltage impulses (with partial discharges) at elevated temperatures. This method is only applicable as a comparative examination under a given sample preparation and testing environment. The comparative nature of this document lies in the fact that the lifetime under partial discharges depends on a large number of influencing factors in the sample preparation and test conditions which could not all be thoroughly investigated so far.
This document applies to round and rectangular magnet wires.

General Information

• Status: Published
• Publication Date: 07-Aug-2025
• ICS: 29.060.10 - Wires
• Technical Committee: TC 55 - Winding wires
• Drafting Committee: WG 1 - TC 55/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 08-Aug-2025
• Completion Date: 29-Aug-2025

Overview

IEC TS 63263:2025 - Winding wires: Electrical endurance under high frequency voltage impulses describes a standardized test method to evaluate the lifetime of magnet (winding) wires exposed to high‑frequency voltage impulses that generate partial discharges at elevated temperatures. The Technical Specification is intended as a comparative test procedure (not an absolute lifetime prediction) because lifetime under partial discharge depends on many specimen‑preparation and test‑condition variables.

The document applies to round and rectangular magnet wires and complements existing winding‑wire standards.

Key topics and technical requirements

• Scope & comparative nature: method for comparative endurance testing under defined preparation and environment; not an exhaustive lifetime model.
• Specimen types & preparation: guidance for wrapped and enameled round wires and rectangular wires; specimen preparation references IEC 60172:2020 and IEC 60851-5:2008.
• Test equipment:
  • Pulse power supply / impulse generator per slot (to avoid cross‑influence).
  • Timing device/fault detector to stop individual timers on failure.
  • Oven with forced air circulation (temperature control ±3 °C).
  • Oscilloscope with bandwidth >50 MHz and differential probe >50 MHz.
• Impulse wave characteristics:
  • Impulse repetition rate: at least 20 kHz ± 0.4 kHz.
  • Impulse rise time: ≤ 100 ns ± 10 ns.
  • Steady‑state impulse magnitude typically up to ±1 500 V; overshoot (Ua) controlled (recommended ≤ 3% of peak).
  • Duty cycle close to 50%.
• Failure criteria & measurement:
  • Timers stop when fault current exceeds set thresholds (e.g., >40 mA for round wire).
  • Optional breakdown voltage checks (example: 300 V/mil).
• Environment & handling: ambient test conditions and handling procedures to avoid contamination or mechanical damage.

Practical applications & users

Who uses IEC TS 63263:2025?

• Wire manufacturers validating enamel, tape‑wrapped or cured coatings.
• Motor, transformer and generator designers assessing winding wire durability under impulse stress and partial discharge.
• Test labs and quality control teams performing comparative evaluations between wire grades or process variants.
• R&D teams developing new insulation systems and accelerated test protocols.

Practical value:

• Enables comparative ranking of wire types and insulation processes when exposed to HF impulse and partial discharge stress.
• Helps identify materials/process changes that improve electrical endurance of winding wires.

Related standards

• IEC 60172:2020 - temperature index test procedures for winding wires
• IEC 60851‑5:2008 - winding wires - electrical properties (specimen prep)
• Series: IEC 60851 (test methods), IEC 60317 (wire specifications), IEC 60264 (packaging)

Keywords: IEC TS 63263:2025, winding wires, high frequency voltage impulses, partial discharges, magnet wire, electrical endurance, impulse test, test method.

Standards Content (Sample)

IEC TS 63263 ®
Edition 1.0 2025-08
TECHNICAL
SPECIFICATION
Winding wires - Test methods - Electrical endurance under high frequency
voltage impulses
ICS 29.060.10  ISBN 978-2-8327-0625-1

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CONTENTS
FOREWORD. 2
INTRODUCTION . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General information on test methods . 6
5 High frequency impulse test equipment . 7
5.1 General . 7
5.2 Power supply . 7
5.3 Timing device . 8
5.4 Test oven and specimen placement . 8
5.5 Oscilloscope . 8
6 Test specimens . 9
6.1 Round wire . 9
6.1.1 Specimen preparation . 9
6.1.2 Initial screening test . 9
6.1.3 Specimen preconditioning . 9
6.2 Rectangular wire . 9
6.2.1 Specimen preparation . 9
6.2.2 Initial screening test . 9
6.2.3 Specimen preconditioning . 10
7 Test method . 10
7.1 Test impulse characteristics . 10
7.2 Test procedure . 10
7.3 Report . 11
Bibliography . 12

Figure 1 – bipolar voltage impulse (3.1) waveshape parameters . 7
Figure 2 – Example of specimen mounting and placement by clamp . 8

Table 1 – Proof voltage for enameled round wire . 9
Table 2 – Example of typical test impulse characteristics . 10
Table 3 – Example of typical test impulse voltage for enameled round wires . 10
Table 4 – Example of typical test impulse voltage for tape wrapped and cured round or
rectangular wire . 11
Table 5 – Example of typical test impulse voltage for enameled rectangular wire . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
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Winding wires - Test methods - Electrical endurance under high frequency
voltage impulses
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rights.
IEC TS 63263 has been prepared by IEC technical committee 55: Winding wires. It is a
Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
55/2068/DTS 55/2073/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
This Technical Specification forms an element of a series of standards which deals with
insulated wires used for windings in electrical equipment. The series has three groups
describing:
a)
...