Page 56
Figure
61
is the Amptector II-A trip unit with front cover
removed, showing all
of
the calibration marks
on
the
dials. The ranges
of
current settings
in
multiples
of
sen-
sor rating and time delay are as follows:
1.
Long-delay pick-up
.5
to 1.25 X sensor rating
2.
Long-delay 8 to 36 seconds, at 6 X
sensor rating
Over these ranges tripping will always occur within the
time band shown
on
Curve
No.
1,
page 59. The bottom
of
the band is called the resettable delay. If the overload
subsides
in
less than the resettable delay time, resetting
of
the trip unit will occur within a few cycles after the load
drops to less than 90%
of
the pick-up setting.
3.
Short-delay pick-up 4 to 10 X sensor rating
4.
Short delay .18 seconds to .50 seconds
or
11
to 30 cycles at 60
Hz,
at 2.5 X pick-up setting.
Over these ranges tripping will always occur within the
time band shown
on
Curve
No.
1,
page
59.
Although the
time adjustment
is
continuous, three time bands are cali-
brated as shown
on
the curve.
5.
Instantaneous Pick-up 4 to 12 X sensor rating
Three different combinations
of
trip elements are pro-
vided. Those combinations with the corresponding Amp-
tector
11-A
model designations as follows:
1.
Long Delay
Instantaneous
DU
(DUAL)
2.
Long Delay
Short Delay
3.
Long Delay
Short Delay
Instantaneous
SE (SELECTIVE)
TR (TRIPLE)
Each Amptector II-A trip unit has a terminal block acces-
sible on the front
of
the circuit breaker front panel.
Figure 59 shows a typical standard wiring diagram, which
includes the Amptector II-A trip unit terminal block. The
following table explains the markings
of
the terminals:
A Sensor phase A
ON
Output negative*
B Sensor phase B
C Sensor phase C
N Sensor neutral
DN
Test point (internal neutral)**
DS
Test point**
TP Test point**
OP Output positive*
DI
Test point**
*To Actuator Coil. THIS COIL HAS A POLARITY MARK-
ING
ON
THE POSITIVE LEAD WHICH MUST BE
1.8. 33-790-11
OBSERVED. OTHERWISE THE BREAKER WILL NOT
HAVE OVERLOAD OR FAULT PROTECTION WHICH
COULD RESULT
IN
BODILY INJURY AND/OR SERI-
OUS EQUIPMENT
DAMAGE.
**Terminals marked "test point" are intended to provide
connections for operation
of
the optional test kit.
8.2 THE AMPTECTOR
I-A TRIP UNIT
Amptector I-A trip units perform all
of
the functions
described above for Amptector II-A trip units and
in
addi-
tion provide the following:
1.
Optional adjustable ground fault protection with
resettable operation indicator.
2.
All Amptectors I-A have a trip indicator that will indi-
cate on overload tripping and another that indicates
on
short circuit tripping. (All indicators are reset man-
ually.)
Figure 62 shows the front
of
the Amptector I-A trip unit. A
maximum
of
seven adjustable controls with screwdriver
adjustments may
be
provided for setting the following
characteristics:
1.
Long-delay current pick-up
2.
Long-delay time
3.
Short-delay current pick-up
4.
Short-delay time
5.
Instantaneous current pick-up
6.
Ground current pick-up
7.
Ground delay time
Fig. 62 Optional Amptector I-A Solid-State Trip Unit
(396707)
Effective October 1998
Courtesy of NationalSwitchgear.com
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