Rockwell Automation Publication 1606-RM105A-EN-P - July 2020
7
Functional Description
This section describes how the buffer module works in general and some
specific uses.
Working Principle
When the power supply provides sufficient
voltage, the buffer module stores energy in the
integrated electrolytic capacitors. If there is a
voltage dip or loss, this energy is released to the
DC bus in a regulated process.
Bridge Mains Faults without Interruption
Statistics show that 80% of all mains faults last less
than 0.2 seconds. The buffer module bridges any
mains faults of this length. This increases the
reliability of the system as a whole.
Extend Hold-up Time
Once mains power fails or is switched off, the
buffer unit continues to provide the load current
for a defined period. Process data can be saved and
processes can be terminated before the DC power
switches off. Controlled restarts are then possible.
Easily Add and Expand
The buffer module does not require any control
wiring. It can be added parallel to the load circuit
at any given point. Buffer modules can be
connected in parallel to increase the output
ampacity or the hold-up time.
Figure 1 - Typical Wiring Diagram
Figure 2 - Transfer Behavior
PE
L
+
-
N
Power
Supply
+
-
Load
+
-
Buffer
Module
optional
Buffer
Mode
Supply
Voltage
Power
Supply
Output
t
t
Transfer Threshold
Power
Supply
Mode
Power
Supply
Mode
DC
Charge
Discharge
Storage
AC
DC
Buffer Module
AC
DC
Buffer Module
DC
Buffer
Module
Power
Supply
Load
AC
+
-