Page
12
l.B.
694C694-02
11
Digitrip Trip Unit
El
Nameplate
El
Shutter (Levering Shaft Access)
11
Open-Close Indicator
Ill
Push to Close Button
IE
Spring Charge Indicator
m Remove Assist Handle
Ill
Padlock Plate
Ill Emergency Charge Handle
II
Drawout Position Indicator
El
Push to Trip Button
Figure 3-3 Typical OSI/ Faceplate
3-4.2 PRIMARY STATIONARY CONTACT
ASSEMBLY
The stationary contact assembly consists of butt type
main contacts which carry the main continuous load cur-
rent. It is comprised of a multiplicity of individual fingers.
Each finger is hinged at the upper end under controlled
pressure. The stationary arcing contacts are similar for
all frame sizes and consist of two parallel fingers, one on
each side of the upper main terminal. They are spring
loaded toward each other by compression springs and
have arc resisting tips. The previously described moving
arcing contact wedges the stationary contact fingers
apart as the breaker closes.
In
addition, the parallel
action of the magnetic fields of the currents in each arc-
ing contact finger causes the fingers to be attracted
toward each other when closing against fault currents.
This results
in
a "blow-on" action on the arcing contacts.
3-5 INTERPHASE BARRIERS
Glass polyester interphase barriers assist in maintaining
proper clearances and must be in place at all times dur-
Effective
07
/97
Courtesy of NationalSwitchgear.com
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