Technical information

1.2 Motor branch circuit

The motor branch circuit is identified with what is generally called motor

starter.

In fact there are various types of motor starters (called direct, star-delta, with

inversion etc) and for each of them there are special regulations.

This document will initially refer to the simplest case of a direct start then it’ll go

onto considering other mostly common cases. North American and Canadian

Standards are very similar and any differences will be clearly shown.

The motor start can be made with different methods that are called “types”. A

summary table of the recognised types contained in the UL 508 “Industrial

Control Equipment” standard.

It is particularly interesting the recent introduction of “Type F” that joins a “Type E”

motor protector and a contactor in an approved assembly,with its own specific

characteristics which are different from those of the individual components.

BRANCH CIRCUIT