Parallel Connection For Redundancy - Siemens PSU300B Manual

9.2

Parallel connection for redundancy

Connecting several SITOP PSU300M/300B power supplies in parallel for redundancy
purposes is required if especially high demands are placed regarding the availability of a
reliable 24 V power supply.
Using the SITOP PSE202U redundancy module, two 24 V power supplies of the same type
up to 20 A can be decoupled (Figure 9-2 Redundant configuration with two power supplies
and one SITOP PSE202U redundancy module (Page 67)). When one of the devices fails,
then the other automatically takes over the power supply. If one of the power supplies fails,
then this is signaled using an LED on the redundancy module as well as an isolated relay
contact.
For higher output current, each power supply must be connected to a redundancy module
(Figure 9-3 Redundant configuration with two power supplies and two SITOP PSE202U
redundancy modules (Page 68)).
When dimensioning the system, it must be ensured that n+1 redundant connected power
supplies can handle the total power requirement of the remaining n power supplies.
Note
For a high reliability of the supply, it is recommended that the redundant switched power
supplies are fused separately on the line-side and, if possible, be connected to different
power supply networks.
Figure 9-2
SITOP PSU300M/300B
Manual, 11.2014, C98130-A7574-A2-2-7629
Redundant configuration with two power supplies and one SITOP PSE202U redundancy
module
9.2 Parallel connection for redundancy
Applications
67