MPE XR III series, Operator'S Manual

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separately.
3.8.1 Parallel Operation - Direct
The simplest parallel connection involves attaching the positive terminals of all supplies to be
paralleled to the positive point of the load and attaching the negative terminals to the negative
point of the load. The output current controls of each power supply can be separately set. The
output voltage control of one power supply (master) should be set to the desired output voltage;
the other power supply (slave) should be set for a slightly higher output voltage. The master will
act as a constant voltage source; the slave will act as a constant current source, dropping its output
voltage to equal that of the master.
3.8.2 Parallel Operation - Master/Slave
Master/slave parallel operation permits equal current sharing under all load conditions and allows
complete control of output current from one master power supply.
Figure 3.17 illustrates the terminal connection for master/slave parallel operation and salient
control circuitry. The control cable can be fabricated by the user or purchased as an option,
UID46, from the factory. These connections perform the following functions:
1. The current monitoring voltage, IO2, on the master power supply connects to the
external current set point input on the slave power supply. This makes the slave
power supply operate at the same current output as the master power supply
2. The power output digital control line of the master power supply connects to the
start digital control line of the slave power supply. This connection causes the
slave unit to turn on when the master unit is turned on.
3. The standby/alm digital control line of the master power supply connects to the
stop digital control line of the slave power supply. This connection causes the
slave unit to turn off when the master unit is turned off or when a diagnostic
condition appears.
4. Connections between terminals 4, 21, 22, and 23 set the voltage control to
maximum and set over voltage trip and over current trip to set points just beyond
full scale values. This forces the slave power supply to operate simply as a current
source whose current set point is established by the master unit.
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