Method of fitting a coil onto a bobbin

摘要

A method of fitting an overload coil for a circuit breaker onto a bobbin assembly. The overload coil is pre-formed into a helical coil with a pair of terminals and a coil sub-assembly is formed by attaching electrical leads to the terminals of the coil. Separate base and top halves of a split bobbin are assembled so that the pre-formed coil of the coil sub-assembly is held captive therebetween. A sensing tube is fitted through an aperture extending axially through the assembled split bobbin, and the sensing tube is mounted onto a magnetic cradle. Different top halves, such as a voltage coil top half and a high inrush top half may be fitted into a common base half. The invention extends to a bobbin assembly for a circuit breaker, as well as to an overload coil sub-assembly.