IEC 60947-4-2:2011

Overview

IEC 60947-4-2:2011 is an international standard established by the International Electrotechnical Commission (IEC) that specifies requirements for low-voltage switchgear and controlgear, particularly focusing on AC semiconductor motor controllers and starters. This third edition supersedes the earlier 1999 edition and its amendments, providing a comprehensive technical revision aligned with current electrical engineering practices.

The scope covers AC semiconductor motor controllers and starters designed for connection to circuits with a rated voltage not exceeding 1,000 V AC. It includes controllers with or without bypass means and may incorporate mechanical switching elements. This standard forms an essential benchmark for manufacturers and users by detailing construction, performance, testing, and marking requirements to ensure safety, reliability, and interoperability in electrical control systems.

Key Topics

• Scope and Application: Defines semiconductor motor controllers and starters used in low-voltage AC circuits up to 1,000 volts.
• Updated Normative References: Incorporates current EMC requirements and references to IEC 60947-1 to maintain consistency with low-voltage switchgear standards.
• Marking Requirements: Specifies clear marking for electronic relays without thermal memory and tripping times at or below 0 °C ambient to improve operational clarity.
• Performance Testing:
  • Thermal, dielectric, shock, vibration, and salt mist tests ensure durability under diverse environments.
  • New short-circuit testing protocols for devices in the smallest enclosures enhance safety verification.
• Overload Relays:
  • Introduces new time-delay overload relay test criteria and defines new classes of overload current withstand time.
  • Guidance on current settings and thermal influences to optimize control and protection.
• Electromagnetic Compatibility (EMC): Strengthened EMC requirements for emission and immunity reduce the risk of electromagnetic interference in industrial environments.
• Installation and Maintenance: Details normative information, marking, and instructions vital for correct assembly, operation, and upkeep.
• Product Classification and Characteristics: Covers equipment types, rated values, utilization categories, and control circuit parameters to ensure appropriate application.

Applications

IEC 60947-4-2:2011 is particularly applicable in industries and systems that require precise and reliable control of AC electric motors using semiconductor technologies. Typical applications include:

• Industrial Automation: Semiconductor motor controllers and starters used in assembly lines, robotics, and manufacturing plants.
• HVAC Systems: Motor control in heating, ventilation, and air-conditioning units for efficient energy use.
• Pumping and Water Treatment: Control of pumps and motors in municipal or industrial water systems.
• Material Handling: Conveyors, lifts, and other motor-driven machinery requiring smooth operation and protection.
• Energy Sector: Integration of soft starters and semiconductor controllers in renewable energy systems and traditional power generation. The standard ensures that these devices operate reliably under normal and severe environmental conditions while meeting safety and electromagnetic compatibility norms.

Related Standards

• IEC 60947-1: General rules for low-voltage switchgear and controlgear, referenced for foundational definitions and requirements.
• IEC 60947 Series: Includes other parts related to contactors, motor starters, and auxiliary equipment, facilitating a full suite of standards for controlgear.
• EMC Standards: Referenced within the document, these address electromagnetic emission and immunity to ensure compliant and interference-free operation.
• National and Regional Standards: IEC 60947-4-2 serves as a global benchmark that informs regional standards such as UL and EN norms for motor starters and controllers.

Embracing IEC 60947-4-2:2011 guarantees adherence to internationally recognized safety, reliability, and performance criteria for AC semiconductor motor controllers and starters, supporting compliance, operational efficiency, and product interoperability across industries.