Common use of Normal Continuous Capability Clause in Contracts

Normal Continuous Capability. Most manufacturers state that internal bushing current transformers furnished with a piece of equipment have thermal capabilities that equal the capability of the equipment. 1) For a single-ratio or multi-ratio internal bushing current transformer operating at a nominal primary current rating equal to the nameplate rating of the equipment with which it is used, the current transformer shall be rated as having the same thermal capability as the equipment. 2) For a single-ratio internal bushing current transformer with a rating less than that of the equipment in which it is installed, the calculated equipment capability should be reduced by the factor: Ict Ie Where Ict is the current transformer nameplate primary current rating and Ie is the equipment nameplate current rating. 3) For a multi-ratio internal bushing current transformer with a maximum rating equal to the nameplate rating of the equipment in which it is installed, but which is operating on a reduced tap, the calculated equipment capability should be reduced by the factor: It In Where It is the reduced tap current rating, and In is the maximum current rating of the current transformer. If information is not readily available on the continuous thermal rating factor of a bushing current transformer, the manufacturer should be consulted.