Operating Considerations; Auto-Parallel Operation - HP 654 A Series Operating Manual

Figure 4-5. Series 657xA Sense Lead Bypass Network
OPERATING CONSIDERATIONS
Auto-Parallel Operation
Auto-Parallel Wiring
Figure 4-6 illustrates how power supplies can be connected in auto-parallel for increased
current output. You can connect supplies of the same model in auto-parallel as follows;
■ Series 654xA or 655xA - up to three supplies.
■ Series 657xA - up to five supplies.
Use load leads of a sufficient wire size so that the aboslute voltage difference between the -f
output terminal of the "master" supply and the -f output terminal of the first "slave" supply
is kept under 2 V at rated current. This also applies to the voltage difference between the -f
output terminals of the first and second slave supplies. If remote sensing is required, connect
the load to the remote sense terminals of the master supply, as shown by the dashed lines in
Figure 4-6.
Note
To avoid output oscillations with Series 654xA and 655xA supplies, observe
the wiring suggestions given under "External Voltage Control".
General Auto-Parallel Programming
Program only the first ("master") supply in the series; the "slave" supplies automatically
track the master's output. However, the voltage and OVP settings of the slave supplies must
be set higher than the operating voltage of the master supply. This ensures that the slave
supplies will operate in CC mode.
Series 654xA and 655xA Auto-Parallel Programming
Caution
Follow the following operating precautions if you are connecting three of these
models in auto-parallel.
You must use caution when connecting three Series 654xA and 655xA power supplies for
auto-parallel operation. That is because of the OVP crowbar circuits within these supplies. If
the OVP circuit of the second "slave" trips, its crowbar circuit will draw current from the
other two supplies. Although some models can withstand this current, the higher-current
models in each series (particularly the HP 6651A) may be damaged in this situation. Use any
of the following operating techniques to avoid possible problems.
Auto-Parallel Operation User Connections and Considerations 4-9