When adjusting the pick up level on instantaneous de
undervoltage devices, set the gap between the armature
and magnet to
.030
inches using the adjustment screw
as
shown in Fig.
32C.
After setting the pick up level, use this
same adjustment screw to obtain the drop out setting.
Cover the adjustment screw locknut with
RTV.
4.
When this device is installed or replaced, i
tS
positive
ability to trip the breaker must be demonstrated.
ADJUSTMENT
FIG. 32C - CLOSED GAP CHECK
Undervoltage devices trip the breaker when the armature
opens. This causes an extension on the armature to strike
the paddle on the trip shaft. An extension of the other end
of the armature. When the armature is released, this exten
sion stops against a stop which is factory set. To check
positive trip, the armature should be held down, the end of a
1132-inch diameter wire should be inserted against the stop,
and the armature released. If this trips the breaker, the set
ting is correct. The place to insert the wire is shown in Fig.
320.
Note that only the tip of the wire is to be against the
stop.
If the undervoltage device does not have positive tripping
ability, the adjustment screw of the trip paddle assembly on
the trip shaft may
be
turned in increments of half turns until
the check is successful.
When the undervoltage device is closed and the breaker
mechanism is reset, there must be clearance between the
trip paddle and the device armature.
7.9
STATIC TIME·DELAY UNDERVOLTAGE
The
static
time-delay undervoltage system consists of a
time-delay unit which
controls an
instantaneous under
voltage device.
The time-delay unit is
separately mounted
in the
s
w
i
tchg
e
ar and
the undervoltage
device is
mounted
on
the breaker.
Table S lists the catalog numbers available.
INSERT
WIRE
GAGE
FIG.
320
-
POSITIVE TRIP CHECK
If the
a-c
control voltage is any voltage other than
2081240V
ac, a control power transformer (also remotely
mounted with respect to the breake" must be used. This
must have a minimum rating of
100
volt-amperes.
When installed, the voltage to be monitored is connected
across terminals No. 1 and No.
2
of the static delay
box.
The coil of the tripping unit is connected across terminals
No.
4
and No.
5
of the static
box
through the secondary
disconnects of the breaker. The secondary disconnects to
be used will be shown on the breaker wiring diagram.
No more than one undervoltage tripping device should
be used in conjunction with one static time-delay unit.
The static time-delay undervoltage can also be furnished
with a thermotector control unit. Overheating of motor win
dings causes the thermotector, imbedded in the motor win
dings, to open. This de-energizes the undervoltage device
on the breaker and drops the motor load.
7.9.1 ADJUSTMENTS
In the event the system fails, the following checks
are
recommended to determine whether the undervoltage
device on the breaker of the static time delay unit is the
faulty component.
1 . Check input voltages across terminals 1 and
2 on
the
static
box. See
Table
5
for these values.
2.
Check output voltages on terminals
4
and
5
with the
undervoltage device connected.
See
Table
5
for values.
TABLE 5 TIME-DELAY U NITS
CONTROL
APPROXIMATE STEADY STATE
NOMINAL DC COIL
VOLTAGE
DC
OPERATING VOLTAGE
RESISTANCE
TERMINALS
TERMINALS
(OHMS)
CAT. NO.
1 & 2
4 & 5
@ 25°C
TAKYUVT- 1
G- & '
125
voc
50
440
TAKYUVT-2
250VDC
100
1600
TAKYUVT-3
G-
r=;c\
208/240 VAC
1 10/125
1600
25
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