CT QUICK CHANGE ASSEMBLY AND FORCE TRANSMITTING SPACER

摘要

A molded case circuit breaker is provided with a quick change current transformer assembly. The current transformer is used to sense overcurrent conditions and apply a signal to an electronic trip unit to trip the circuit breaker. The quick change assembly includes an insulated removable plate located adjacent an open cavity in the housing in which the current transformer is located. The current transformer is donut-type disposed about a load-side conductor located in a cavity in the housing rigidly fastened to the circuit breaker frame. In order to replace a current transformer, the insulated back-plate is removed. Next the load-side conductor is unfastened and removed from the circuit breaker housing. The current transformer is then removed from the circuit breaker housing. In order to install a new current transformer, the steps are reversed. A force transmitting spacer is disposed adjacent a bight portion of a shunt, connected between a pivotally mounted contact arm and a load-side conductor. The force transmitting spacer transmits magnetic repulsion forces generated between the load-side conductor and the depending leg of the shunt adjacent the load-side conductor to the other depending leg of the shunt. By disposing the force transmitting spacer into the bight portion of the shunt the compression action required between the depending legs of the shunt is eliminated or reduced, thus reducing the blow open time significantly.