Short circuit protector having fold-back trip point for solid st

Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific current responsive fault sensor

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

361 18, 361 93, H02H 308

Patent

active

045133433

ABSTRACT:
A transistor circuit (18) is series connected with a solid state switching device (14) and a load (4) controlled by that device (14) to protect that device (14) from overcurrents resulting from short circuits such as across the load (4). The transistor circuit (18) detects the overcurrent and switches to a high impedance state in response to that detection. The circuit (18) is self-resettable to restore to the low impedance state each half-cycle of applied voltage, thereby to automatically restore the switching device (14) to normal operation immediately upon removal of the short, and is set to initially respond to a level of current sufficiently high to preclude switching in response to inrush currents. Initial switching of the circuit (18) to its high impedance state latches a reduced level detection circuit (R1-R2-Q4) in the transistor circuitry (18) whereby the latter switches to its high impedance state upon detecting lower overcurrent values for each successive half-cycle until the short is removed. The predictability of the response range for the circuit, especially in the reduced level voltage detection mode, is improved by placing a resistor (R5) in series with the control switching transistor (Q3) for the circuit.

REFERENCES:
patent: 3390306 (1968-06-01), White
patent: 3517264 (1970-06-01), Anderson, Jr.
patent: 3638102 (1972-01-01), Pelka
patent: 3851218 (1974-11-01), York
patent: 4271448 (1981-06-01), Pond

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Short circuit protector having fold-back trip point for solid st does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Short circuit protector having fold-back trip point for solid st, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Short circuit protector having fold-back trip point for solid st will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-39562

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.