CIRCUIT INTERRUPTER WITH DIGITAL TRIP UNIT AND MEANS TO ENTER TRIP SETTINGS

摘要

A circuit breaker includes a digital electronic trip unit having a microprocessor. The front panel of the trip unit includes a potentiometer connected across a reference voltage, and a numeric display device. The potentiometer is adjusted by an operator to enter a value of a parameter defining the time-current characteristic of the circuit breaker. An analog-to-digital converter receives the voltage supplied by the potentiometer and converts it to a digital quantity for use by the microcomputer in performing limit checks with the current flow through the contacts of the breaker. The microcomputer formats the converted digital value of the potentiometer voltage and supplies it to a front panel-visible numeric display so that the value of the potentiometer setting as interpreted by the microcomputer in defining the time-current trip characteristic is presented on the numeric display to provide real-time feedback to the operator as he adjusts the parameter value.