IEEE C62.21-2003

This guide covers the application of surge voltage protective equipment to AC rotating machines rated 1000 volts and greater. The guide does not cover motors applied in solid-state switched adjustable speed drives. Part 1 covers the insulation surge withstand strength of motors and generators with windings having form-wound multi-turn coils and the application of surge protection to form-wound multi-turn coil motors. Part 2 will cover application of surge protection to generators with form-wound multi-turn coils, plus insulation surge withstand strength and surge protection of single-turn coil generators and motors.

This guide is intended to aid engineers at all levels of surge protection knowledge in deciding whether particular machines should have surge protection. The guide may be used in estimating the surge withstand capability and switching surge exposure of ac rotating machinery in usual, not extreme exposure, installations. The manufacturer should be contacted for specific insulation surge voltage withstand values for machinery of particular interest or importance. For those machines which should be protected, the purpose is to provide guidance in selecting and applying the protective devices. A simple look-up method using tables and a graph is provided for quick estimation of surge rise times and surge voltage levels, and for general use where accuracies in the order of 10% to 15% are acceptable. This method is based on single-phase analysis, neglecting the influence of ground mode surge propagation. A more complex method is provided by formulas to model the three-phase and ground mode propagation. The formulas can be used with calculators or personal computers.

Revision Standard - Inactive-Reserved. Project scope: This guide covers the application of surge voltage protective equipment to AC rotating machines rated 1000 volts and greater. The guide does not cover motors applied in solid-state switched adjustable speed drives. Part 1 covers the insulation surge withstand strength of motors and generators with windings having form-wound multi-turn coils and the application of surge protection to form-wound multi-turn coil motors. Part 2 will cover application of surge protection to generators with form-wound multi-turn coils, plus insulation surge withstand strength and surge protection of single-turn coil generators and motors. Project purpose: This guide is intended to aid engineers at all levels of surge protection knowledge in deciding whether particular machines should have surge protection. The guide may be used in estimating the surge withstand capability and switching surge exposure of ac rotating machinery in usual, not extreme exposure, installations. The manufacturer should be contacted for specific insulation surge voltage withstand values for machinery of particular interest or importance. For those machines which should be protected, the purpose is to provide guidance in selecting and applying the protective devices. A simple look-up method using tables and a graph is provided for quick estimation of surge rise times and surge voltage levels, and for general use where accuracies in the order of 10% to 15% are acceptable. This method is based on single-phase analysis, neglecting the influence of ground mode surge propagation. A more complex method is provided by formulas to model the three-phase and ground mode propagation. The formulas can be used with calculators or personal computers.