BS 4999-145:1987

Specifies terminations for rotating machines rated up to 15 kV a.c. r.m.s. Types of terminations. Creepage and clearance distances, current ratings of connections, definitions.

This part of this British Standard specifies types of and performance requirements for winding terminations for rotating electrical machines rated for a.c. voltages up to 15 kV r.m.s. Minimum creepage and clearance distances appropriate to the rated voltages are also specified.

This standard does not specify requirements for the ability of the terminations of the following machines to withstand a high energy fault:

1. machines rated for voltages up to and including 660 V, which it is assumed, would be protected by fuses or other energy limiting devices.
2. machines rated for voltages of 1 100 V and above either protected by fuses or other energy limiting devices or intended for operation on a system where the nominal short-circuit capacity is lower than the relevant value given in Table 1.

The standard applies to terminals, terminal boxes and terminal enclosures, but it does not specify requirements for flameproof terminal enclosures.

The choice of a particular termination will be largely governed by the service and environmental conditions, but the standard is also relevant to the various types of cables normally used, including aluminium and, where applicable, cable sealing and dividing boxes. It is outside the scope of this British Standard to cover external supply cables in detail, but insofar as the design of the terminals is concerned, essential data are listed.

Winding terminations for small power machines having rated outputs up to and including 0.75 kW or kV·A per 1 000 r/min, such as those specified in BS 5000-11, are not covered by this standard.

NOTE The titles of the publications referred to in this standard are listed on the inside back cover.