Noise And Impedance Effects; Inductive Loads; Connecting Single Loads, Local Sensing (Default) - Delta D750 User Manual

User Manual
D750
DC Power Supply
2.8.4 Noise and Impedance Effects
To minimize the noise pick up 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 Grounds crew. 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 of power supply, 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.

2.8.5 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.

2.8.6 Connecting single loads, local sensing (default).

Fig.2-2 shows recommended load and sensing connections for a single load. The local
sense lines shown are default connections at the rear panel J2 sense connector. Local
sensing is suitable for applications where load regulation is less critical.
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+V
Power
- V
Supply
-Rem.sense
-Local sense
+Local sense
+Rem.sense
Fig.2-2: Single load connection, local sensing
+
Load
-
Load lines, Twisted
pair, shortest length
possible.