B&K Precision 1745A - Manual - Manual (Page 19)

19
OPERATING INSTRUCTIONS
CONNECTING TWO POWER SUPPLIES IN PARALLEL
Two power supplies may be connected in parallel to double the
maximum load current. In this configuration the two supplies will
provide two 0-35 volt output at up to 20 amps (heavier gauge
hook-up leads are advisable). Current equalizing resistors must be
used as shown in Fig. 9. However, the protective current limiting
feature will prevent damage if current is temporarily unbalanced
during set-up.
When connected in parallel and operating in the constant
voltage mode, determine the total load current limit and preset the
current limiting for each power supply to half the total load
current value. Then when the load is connected, set the
VOLTAGE controls on the two power supplies for equal voltage
readings. This should also provide approximately equal current
from each supply. Add the two current readings together for total
load current, or connect an external ammeter in series with the
load.
If the current equalizing resistors are not well matched, it is
preferable that the voltages be slightly unbalanced to achieve
current balance. Be sure that the supplies are adequately
balanced so that both remain in the CV mode.
When connected in parallel and operating in the constant
current mode, the VOLTAGE controls of both supplies should
be preset to the same value. Then when the load is connected, the
CURRENT controls of the two supplies should be adjusted for
approximately equal current from each unit. Be sure that both
supplies remain in the CC mode.