IEC 60092-301:2025

Overview - IEC 60092-301:2025 (Generators and motors)

IEC 60092-301:2025 is the fourth edition of the IEC international standard for electrical installations in ships, specifically covering generators and motors. It applies to all rotating electrical machines rated at 750 W or more for marine use, including excitation machines and relevant requirements for prime movers driving generators. This 2025 edition is a technical revision of the 1980 edition (and subsequent amendments) and adds explicit service conditions and alignment with IEC 60034‑1:2022.

Key topics and technical requirements

The standard sets out requirements that ensure safe, reliable shipboard operation of generators and marine motors:

• Scope and applicability: rotating machines ≥ 750 W; includes excitation machines and prime movers.
• Service conditions: defined limits for inclination, vibration and ambient temperatures as per IEC 60092‑101.
• Mounting and orientation: machines above 500 kW should have shafts parallel to the ship’s longitudinal axis; vertical mounting permitted with special considerations.
• Reference compliance: machines must meet relevant parts of IEC 60034 (all parts) and related IEC 60092 parts for high-voltage or propulsion systems.
• Water ingress and cooling: water-cooled systems must prevent entry of water into machines; leakage detectors recommended where intrusion risk exists.
• Moisture control: machines above 100 kW require measures (e.g., space heaters) to prevent condensation when idle.
• Mechanical balance: balancing to ISO 21940-11 quality G 2.5 with full‑size key if applicable.
• Shaft currents: measures to prevent shaft-to-bearing currents; bearing insulation recommended for motors running from frequency converters.
• Terminals, lubrication, running speed, testing and enclosure protection: clear requirements for safe installation and maintenance.
• Generator-specific requirements: DC and AC generator tolerances, transient and short‑circuit behavior, emergency generator rules, excitation systems, and parallel operation/load sharing.
• Prime movers: governing characteristics, lubrication, and cyclic irregularity limits.
• Documentation and rating plates: required markings and technical documentation for certification and operation.

Applications and who uses this standard

IEC 60092-301 is used for:

• Shipbuilders and naval architects for design and specification of shipboard electrical machines
• Marine electrical equipment manufacturers (generators, motors, exciters)
• Classification societies and flag administrations for certification and compliance checks
• Ship operators, maintenance teams and system integrators for installation, testing and lifecycle maintenance
• Designers of electric propulsion systems and emergency power plants

Practical uses include equipment selection, procurement specifications, installation checks, commissioning tests, and maintenance procedures for marine generators and motors.

Related standards

• IEC 60034 (Rotating electrical machines) and IEC 60034‑1:2022
• IEC 60092‑101 (Definitions and general requirements)
• IEC 60092‑201 (System design)
• IEC 60092‑501 / 503 (Propulsion and high-voltage ship systems)
• ISO 21940‑11 (Rotor balancing)
• ISO 8528‑5 (Engine-driven generating sets)

Keywords: IEC 60092-301, electrical installations in ships, ship generators, marine motors, rotating electrical machines, IEC 60034-1, shaft currents, moisture prevention, rotor balancing.