Circuit breaker demonstrator and distribution circuit protection coordinator apparatus

Apparatus for displaying the time-current response characteristics of circuit protective devices, said apparatus comprising, in combination:

• A. a graphical display including a fixed vertical time coordinate in logarithmic scale and a fixed horizontal current coordinate in logarithmic scale;
• B. first variable means connected to said display for selectively electrically generating for portrayal on said display a first portion of a time-current response curve representing the long time response characteristics of a selected circuit protective device;
• C. second variable means connected to said display for selectively electrically generating for portrayal on said display a second portion of said time-current response curve representing the short time response characteristics of the selected circuit protective device;
• and
• D. third variable means connected to said display for selectively electrically generating for portrayal on said display a third portion of said time-current response curve representing the instantaneous response characteristics of the selected circuit protective device,
• (1) said first, second and third curve portions as potrayed on said display providing a true and continuous graphical display in log-log coordinate scale of the selected circuit protective device's time-current response curve over the entire overcurrent range.