Vega Customer Applications Manual
Section 3 - Analogue Secondary options
Rev. A3: October 2003
Page 15 of 48
N+1 redundant & "Hot Swap"
Vega power supplies can be connected in 1+1 redundant with active current share utilising the "N" option. This allows
one of the power supplies to fail and the system remain running as the other power supply can drive the required
current. Further, whilst both power supplies are running neither supplies more power than the other so the currents
and hence stresses and heating effects are evenly shared. This principal can be extended to N+1 redundant where
any number of power supplies can be connected in parallel actively sharing the required current such that the failure of
one will not affect the system.
The principal can be extended further to "hot swap". This allows a failed power supply to be removed and replaced
with the system fully live and driving the full load current. Normally a Vega power supply would be incorporated in a
"shuttle" on sliding rails with a "hotswap" self aligning output which can be easily connected / disconnected from a
system.
The diagram below shows a typical arrangement for 1+1 redundant system.
+S
+V
-S
-V
+S
+V
-S
-V
Pin 8/9
Pin 8/9
MODULE 1
MODULE 2
1+1 Current sharing system Remote Sensed.
Remote sense is NOT TRUE redundant function.
Shuttle 1 or 2 failing can influence shuttle 2 via the
sense lines.
Not shown are the L, N and Earth connections. It is
important when designing connectors for hot swap
applications that the EARTH is made first and broken
last (ie use an extended earth pin).
The +S and -S should be made first and broken last
also.
Remember a lot of heat may be dissipated by the
blocking diodes. Be sure to rate them correctly.