l Units of mixed power (1 kW and 2 kW) with the same voltage rating can participate in current shar-
ing. This lets you take advantage of the higher current capability of the 2 kW units.
Sharing Cable Fabrication
A connector plug is supplied with each unit, but the cable itself must be fabricated. You must provide
the cable wiring. The following figure illustrates the cable assembly. Note that pin 1 is not used.
Briefly:
l Keep wire size around AWG 20 or 22 (0.5 mm
2
).
l Strip wire insulation back 7 mm.
l Insert the wires into the connector and tighten the screw terminal.
l Twist or bundle the wires to reduce noise. Shielding is not required.
l Connect pins 2 together; connect pins 3 together.
Load, Sense, and Sharing Connections
The following figure shows how to connect three units in parallel. Note the following
recommendations:
l Install the paralleled units relatively close to each other in a stacked configuration.
l Bus bars can be used instead of cables to parallel the output terminals in a stacked configuration.
Place the bus bars on the inside of the output terminals.
l Keep the wiring from the power supplies to the load as short as possible and twist or bundle the
leads to reduce lead inductance and noise pickup. The goal is to always minimize the loop area or
physical space between the + and - output leads from the power supply to the load.
l If the units cannot be located close together, a symmetrical arrangement of separate load-wire
pairs of equal length connecting to a common load point is highly recommended. This provides the
best possible dynamic response.
l Connect the sense leads of each paralleled unit directly to the load.
Although the following figure shows the recommended use of remote sensing, local sensing may be
used if absolutely necessary. However, with local sensing, the sharing circuits will work properly only
if the voltage drop measured between the local sense points of any unit to the local sense points of
any other paralleled unit is less than 0.5% of the maximum voltage rating of the units.
Keysight N6900/N7900 Series Operating and Service Guide 77
2 Installing the Instrument
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