IEC TS 60034-34:2020 PDF

Overview

IEC TS 60034-34:2020 is a Technical Specification from the IEC that defines specific requirements for AC adjustable speed rolling mill motors where their performance differs from conventional AC motors. It covers motor design, thermal behaviour, overload capacity, testing and verification under the variable-speed, high-duty conditions typical in rolling-mill applications. The document helps manufacturers, OEMs, mill operators and test engineers ensure motors meet performance, reliability and safety expectations for rolling mills.

Key topics and requirements

• Scope and terminology: Definitions tailored for adjustable-speed control, rolling operation patterns and monitoring/protection sequences.
• Terminal voltage and speed characteristics: Guidance on motor terminal voltage behaviour (induction and synchronous) across speed ranges.
• Duty type & temperature class: Selection of duty (e.g., continuous or intermittent), winding temperature rise (Class B/F) and evaluation of winding temperature deviation within one rolling cycle.
• Overload capacity: Definitions of various overload types (continuous and short-time) and limits; Annex A specifies short-time overload capability patterns.
• Thermal life / insulation evaluation: Methods to estimate reduced insulation life when motors are operated beyond design limits (simplified and precise approaches in Annexes C and D).
• Mechanical requirements: Shaft/transmission strength, torsional vibration considerations, thrust and radial loads, overspeed and mounting code guidance.
• Withstand voltage: Requirements and tests for ground insulation, turn-to-turn insulation and rotor/damper bars under converter-fed conditions.
• Factory and site tests: Required factory tests and recommended site trials, including vector-control verification, acceleration/deceleration, no-load characteristics and bearing temperature rise tests.
• Grounding and bearing protection: Protective earthing (PE), functional earthing (FE) and measures against bearing currents.
• Control system guidance: Informative annexes provide typical control system configurations for induction and synchronous motors and explain significance of acceleration/deceleration tests.
• Documentation: Rating plate requirements and test records.

Practical applications and users

This TS is intended for:

• Motor manufacturers designing AC adjustable speed rolling mill motors for hot/cold, continuous or reversing rolling mills.
• OEMs and system integrators who specify motor-drive systems (inverters, vector control, synchronous systems).
• Plant operators, maintenance and commissioning teams performing factory acceptance tests (FAT) and site trial operations.
• Design engineers assessing overload scenarios, insulation life, bearing protection and mechanical loads for rolling mill drives.

Practical benefits include improved motor selection for heavy-duty rolling patterns, clearer factory/site test protocols, and guidance to reduce unexpected insulation degradation and mechanical failures.

Related standards

• IEC 60034 series (rotating electrical machines) - provides general requirements for motors; IEC TS 60034-34:2020 supplements these for rolling-mill specific, adjustable-speed applications.