Shunt Trip Attachment; Undervoltage Trip Attachment; Undervoltage Trip Attachment - Construction Details - Westinghouse DE-ION DB-75 Instructions Manual

MAIN TENANCE

UNDERVOLTAGE TRIP ATTACHMENT

The undervoltage trip (Figure 13) mounts
on top of the platform, to the right of the
shunt trip. Its fun ction is t o trip the
breaker when the voltage f alls to between
30 and 60 percent of normal.
The moving coil is normally held magnet­
ically against the stationary core to hold
the rod and consequently the reset lever in
the reset position. When the coil voltage is
reduced sufficiently, the reset lever spring
overcomes the magnetic attraction of the cores
and rotates the reset lever clockwise.
F"RAME
ROD
13-
FIG. UNDERVOLTAGE TRIP ATTACHMENT- CON STRUCTION DETAILS
24-
As
+
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I
---
I
--
I
+
I
I
CROSS BAR
RESET LEVER
STATIONARY
CORE
t he reset lever rotates,
a gainst the latch to release it from its
latch plate. When the latch releases,
trip s pring rotates the trip lever to trip
t he breaker. The linkage is reset by the
c ross bar as the breaker opens.
Always connect the coil to the line side
o f the brea ker unless t h e attachment is
e quipped with time delay device.
case, the time delay will delay the tripping
of the breaker long enough to permit ener­
g ization of the undervoltage coil from the
load side. Do not use an auxiliary switch
contact in the undervoltage
I
I
I
I
I
I
TRIP
SPRING
the pin pushes
the
In this
"
circuit.
LATCH
PUSH
PIN
TRIP
LEVER
LB. 35-240-1