GE Power Break II, Руководство пользователя

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MicroVersaTrip Plus™ and PM™ Trip Units
Long-Time Protective Functions
Long-Time Function/Current Setting (Standard)
The adjustable long-time setting is based on multiples of
"X", the rating plug a m p rating. There are 11 possible setting
from 50% to 100% of rating plug amps, in 5% steps. This
setting establishes the current setting of the breaker, which
is the current the breaker will carry continuously without
tr ipping. Multiplying the long-time setting by the rating plug
value establishes the value of "C". For example, a breaker
with a 95% long-time setting and 500 amp rating plug (xi
would have a 475-amp current setting, or value of C.
( Long-time current setting (C)= (0.50 to1.00) X rating plug
(XI)
Long-time function or current setting
Long-Time Delay (Standard)
Long-time delay varies the time it will take the breaker to trip
under sustained overload conditions. It permits the breaker
to ride through momentary predictable overloads (e.g., mo­
tor starting) without tripping. There are 4 time bands that
provide nominal delays from 3
to 25 seconds at 600 % of the
breakers current setting, or value C.
Long-time delay
16
I nstantaneous Function (Standard)
All Power Break® I I breakers have either the standard in­
stantaneous tr i p function or the "high range" instantaneous
function. The instantaneous trip point establishes the value
of current that will tri p the breaker without i ntentional time
delay. Instantaneous trip times are 50 milliseconds, or less.
I nstantaneous tri ps are the result of severe overcurrent or
short-circuit conditions, and damage to the power systems is
minimized by immediate tripping. Standard settings are ad­
justable in increments of .5 of X of the r ating plug amp value
(X). See Table 17.1 for allowable values. The trip unit will limit
the instar:Jtaneous tri p level so that the breaker withstand
rating is not exceeded.
Standard instantaneous function
Short-Time Functions (Optional)
Short-Time Pickup
The short-time pickup functions controls the level of high
current the breaker will withstand for a short per iod of time
to allow downstream devices to clear faults without
tripping
the breaker. Settings are adjustable in increments of 50% of
the breaker
current setting (C). See Table 17.1 for allowable
values. If the instantaneous setting is set for lower values of
current than the short-time function, the instantaneous func­
tion prevails.
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Short-time pickup function
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