Product specifications

131
Power Products AC Power and Load Connections (Continued)
Applications Information
More detailed specifications at www.agilent.com/find/power
b. Multiple ungrounded loads.
This alternative applies when sepa-
rate pairs of load leads connect two
or more loads and none of the load
circuits has an internal connection to
chassis or ground (Figure 5). Use the
positive or negative DC distribution
terminal as the DC common point.
c. Single grounded load.
When a power supply is connected
to a single load that has a necessary
internal connection to chassis or
ground as in Figure 6, or when a
supply is connected to multiple loads
only one of which has a necessary
internal connection to chassis or
ground as in Figure 7, the load ter-
minals of the grounded load must
be designated the DC distribution
terminals, and the grounded load
terminal is necessarily the DC
common point.
Figure 6
Preferred ground connections for a single
grounded load
Figure 7
Preferred ground connections for
multiple loads, only one of which
is grounded internally
d. Multiple Loads, Two or More of
Which are Individually Grounded.
This undesirable situation must be
eliminated if at all possible. Ground
loop currents circulating through
the DC and load wiring cannot be
avoided so long as separate loads
connected to the same power supply
or DC system have separate ground
returns as shown in Figure 8.
One possible solution is to break
the ground connection in all of
the loads and then select the DC
common point using the multiple
ungrounded load alternative as in (b)
above. Another would be to break the
ground connection in all but one of
the loads and select the DC common
point as in alternative (c). If there
are two or more loads with ground
connections that cannot be removed
and the system is susceptible to
ground loop problems, then the only
satisfactory solution is to increase
the number of power supplies and to
operate each grounded load from a
separate supply. Each combination
of power supply and grounded load
would be treated as in alternative (c).
Power Supply
+S
Load
GND
S.G.
CP and GP
Without Remote Sensing
-S
+
-
Power Supply
+S
Load
GND
S.G.
CP and GP
With Remote Sensing
-S
+
-
With Remote Sensing
Power Supply
+S
Load
No 2
Load
No 1
Load
No 3
GND
S.G.
CP and GP
Without Remote Sensing
-S
+
-
Power Supply
+S
Load
No 2
Load
No 1
Load
No 3
GND
S.G.
CP and GP
-S
+
-
Power Supply
+S
Load
No 2
Load
No 1
Load
No 3
GND
S.G.
Ground
Voltage
Source
-S
+
-
Figure 8
Improperly connected DC distribution system with two
grounded loads forming a ground loop