Quartz crystal units for frequency control and selection. Part 3 : Standard outlines and pin connections.

This document represents a supplementary addendum addressing specific technical updates for a foundational international specification concerning rotary electrical machines. It serves as the third revision in a series of updates designed to maintain the relevance and technical accuracy of the original core standard. The content primarily focuses on refining testing procedures, clarifying measurement methodologies, and incorporating advancements in electromagnetic compatibility and safety requirements for rotating equipment. By issuing this supplementary text, the standardization body aims to ensure that manufacturers, testing laboratories, and regulatory authorities operate under a unified set of technical guidelines without requiring a complete revision of the parent document. This addition typically covers specific operational parameters, material specifications, or environmental conditions that have evolved since the initial release. The text is structured to be integrated seamlessly with the main body of the specification, providing clear references to relevant sections that require modification or expansion. Its purpose is to harmonize technical expectations globally, facilitating international trade and ensuring consistent performance and safety across different jurisdictions and industrial applications.