Westinghouse DB-15 Instructions Manual page 17

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CURVE A
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CURVE C
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FIG. SA.
picked up by flux inside of the lower core after it
has saturated and bodily raises the sealed tube
which trips the breaker.
The short time delay is obtained by the use of a
pressure-operated by-pass valve in the timing stem.
-
70 AMP. LOAD BREAKER WITH
a
LONG TIME DELAY INST TRIP
-
300 AMP. BREAKER WITH LONG TIME
a
DELAY INTERMEDIATE SHORT TIME
DELAY
Time-current Characteristics o£ DB-25 Circuit Breakers Equipped with Typical Overcurrent Tripping
Devices for Motor Starting and Selective Operation
D -YI-+
c
CURRENT IN AMPERES
Otherwise, the construction and operation of the
tripping device embodying this delay is the same
as described above for the device with the long
time delay.
After the breaker has been tripped with time
"D B "
AIR CIRCUIT BREAI4�ERS
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17