Howard R Peiffer

US Patent:

40285910, Jun 7, 1977

Filed:

Oct 22, 1975

Appl. No.:

5/624810

Inventors:

David Kahn - Harrisburg PA
Howard Richard Peiffer - New Cumberland PA

Assignee:

AMP Incorporated - Harrisburg PA

International Classification:

H02H 300

US Classification:

361 11

Abstract:

A polyconductor device is connected in series with a pair of current carrying contacts of a relay switch to delay the current surge through the contacts during the closure thereof. The polyconductor device has a negative temperature-resistance characteristic such that its electrical resistance value at temperatures below a predetermined transition temperature is at least several orders of magnitude larger than its resistance value at temperatures above the transition temperature. When the contacts are initially closed, only a small electric current passes through the polyconductor device which is in its high resistance state. After a predetermined time, the current heats the device to a critical temperature at which time polyconductor device switches to its low resistance state and the current flows essentially unimpeded thereby. During the heat-up time the contacts of the relay switch have completed bouncing and are in a stable, closed condition.