Chapter 1 - General Description
User Manual
N
N
e
e
t
t
w
w
o
o
r
r
k
k
P
P
o
o
w
w
e
e
r
r
S
S
w
w
i
i
t
t
c
c
h
h
1.2 Design Concept
Figure 5.1.1 in Chapter 5 shows the Power circuit diagram for Network Power Switch. Source 1 & Source 2 are the
two synchronized power sources with fuse switches FS1 & FS2 & pair of SCR’s TA1 & TB1 in series with each path
&TA2 and TB2 in the neutral path
Logic dictates that at any time only one pair of back-to-back connected SCR’s in the line and neutral should conduct.
This routes the input power to the output load. Should the load feeding source fail due to any reason; the other source
takes over automatically in less than 6 ms.
This ensures that the critical load always receives the power & changeover time is less than the tolerance limit set by
IEEE 446 (CBEMA curve) for information technology equipments. The change over is always with break, which
ensures that in no case two sources get paralleled.
Priority source can be selected through front panel switch. The live mimic on front panel indicates which source is on
priority & which is feeding the load. Figure 1.4 shows the details of live mimic panel.
Page 1-2
(03/04)
