l.B.
33·790·1
I
8.1
THE AMPTECTOR II-A TRIP UNIT
Improvements have been made to the Cutler-Hammer
Amptector and the standard model is now Amptector II-A.
Wiring and terminal changes were made to provide
method of testing with a tester. Refer to Section 8.7.6 for
testing with Amptector Test Kit.
Another change was to modify the long delay curve to
nearly an 1
2
T function. The revised curve shows this
change. See Curve
No.
1.
The Amptector II-A is standard equipment on all DS and
DSL circuit breakers. It provides approximately equiva-
lent functions as the electro-mechanical trip devices pro-
vided on some circuit breakers but with the superior
operating capability of solid-state devices. The Amptector
I-A is an optional (extra cost) tripping system which can
be provided when ground fault protection or trip indica-
tors are required. Both trip units have the same reliability
and repeatability inherent
in
solid-state design.
As shown
in
Figure 5 the Amptector trip unit is at the top
front of the breaker. Figure 60 shows a close-up of the
front of the Amptector II-A trip unit. There can be a total of
five adjustable controls, with screwdriver adjustment.
These are for setting the following characteristics:
1. Long-delay current pick-up.
LONG
DELAY
CURRENT--------------.
?!CKUP
0.5
to
1.25X
SENSOR
RATING
SHORT DELAY
CURRENT
PICKUP 4 TO
10X
SENSOR
RATING
INSTANTANEOU,
PICKUP 4
TO
12X
SENSOR
RATING
•see
Section
8.4
of
Text
for
Explanation
Fig.
61
Amptector II-A
Trip
Unit with Front Cover
Effective
October
1998
Page
55
2.
Long-delay time.
3.
Short-delay current pick-up.
4.
Short-delay time.
5.
Instantaneous current pick-up.
Note: The term "pick-up" as used here means the
rms value of current at which the Amptector trip unit
timing function begins or instantaneous tripping is
intiated.
Fig. 60 Standard Amptector II-A So/id-State
Trip
Unit
*
---*
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Courtesy of NationalSwitchgear.com
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