Appeal No. 96-2838
Application 08/336,721
This is a decision on appeal from the final rejection of
claims 1 through 4 and 6 through 14. Claim 5 has been
canceled.
Appellants' invention relates to a circuit breaker which
is responsive to sputtering arc faults which can occur when
bared conductors of an electrical system come into close
proximity. The breaker can discriminate between inrush
currents and sputtering arc faults to avoid false trips.
On page 4 et seq. of the specification and Figure 1,
Appellants disclose a circuit breaker 1 protecting an electric
system 7 which includes a line conductor 9 and a neutral
conductor 11. Ground fault detector 5 recognizes line-to-
ground fault 17 and neutral-to-ground fault 19. Current
sensor 21 detects line-to-ground faults and applies the signal
to IC 29. IC 29 turns on SCR 39 which energizes trip solenoid
41 to actuate the trip mechanism 49 to open contacts 51.
Sputtering arc detector 3 recognizes arc fault 15 (Brief
at bottom of page 3). Current sensor 23 produces a rate of
change of current signal, di/dt, for sputtering arc faults.
The di/dt signal is bandwidth limited by low pass filter 67
such that only step increases in current are applied to window
2
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Last modified: November 3, 2007