Installation
2
Series N5700 User’s Guide
29
If remotely located distribution terminals are used, as shown in the
following figure, the power supply output terminals should be
connected to the remote distribution terminals by a pair of twisted
and/or shielded wires. Connect each load to the distribution
terminals separately. Remote voltage sensing is recommended under
these circumstances. Sense either at the remote distribution
terminals or, if one load is more sensitive than the others, directly at
the critical load.
Output Noise and Impedance Effects
To minimize the noise pickup or radiation, the load wires and remote
sense wires should be twisted-pairs to the shortest possible length.
Shielding of sense leads may be necessary in high noise
environments. Where shielding is used, connect the shield to the
chassis via a rear panel ground screw. Even if noise is not a concern,
the load and remote sense wires should be twisted-pairs to reduce
coupling, which might impact the stability of power supply. The sense
leads should be separated from the power leads.
Twisting the load wires reduces the parasitic inductance of the cable,
which could produce high frequency voltage spikes at the load and
the output because of current variation in the load itself.
The impedance introduced between the power supply output and the
load could make the ripple and noise at the load worse than the noise
at the power supply rear panel output. Additional filtering with
bypass capacitors at the load terminals may be required to bypass the
high frequency load current.
Inductive Loads
Inductive loads can produce voltage spikes that may be harmful to
the power supply. A diode should be connected across the output.
The diode voltage and current rating should be greater than the
power supply maximum output voltage and current rating. Connect
the cathode to the positive output and the anode to the negative
output of the power supply.
Where positive load transients such as back EMF from a motor may
occur, connect a surge suppressor across the output to protect the
power supply. The breakdown voltage rating of the suppressor must
be approximately 10% higher than the maximum output voltage of the
power supply.
-
-
Rem.sense
Local sense
ocal sense
Rem.sense
+L
+
Distribution terminal
+V
+V
-V
-V
Load#1
+
Load#3
+
Load#2
+
Power
Supply
