Colin Victor Cornhill

US Patent:

58868607, Mar 23, 1999

Filed:

Aug 25, 1997

Appl. No.:

8/918768

Inventors:

William Weizhong Chen - Cedar Rapids IA
Colin Cornhill - Cedar Rapids IA
Andy Haun - Cedar Rapids IA
Gary Scott - Mt. Vernon IA
Manzoor Ali - Cedar Rapids IA
William Rezac - Cedar Rapids IA
Kevin James Green - Cedar Rapids IA

Assignee:

Square D Company - Palatine IL

International Classification:

H02H 300

US Classification:

361 9

Abstract:

A Positive Temperature Coefficient Resistivity (PTC) element has a resistivity that increases as the temperature increases. Circuit breakers having PTC elements can achieve better overload and short circuit protection than existing products. Breakers with PTC elements can also be combined with ground fault detection circuits to activate the circuit breaker under ground fault conditions that are less severe than the overcurrent conditions that would normally activate the circuit breaker. A shunt trip assembly incorporating a PTC resistor reduces the required power rating of the clearing switch.