Xantrex Technology XFR 2800 - Manual (Page 60)

Local Operation
Standard Operation
58 Operating Manual for XFR 2.8kW Series Power Supply
Figure 3.1 Operating Modes
Constant Voltage Mode Operation The power supply will operate in constant
voltage mode whenever the load current I L is less than the current limit setting I
SET
,
or: I
L
< I
SET
(Note: I
L
= V
SET
/ R
L
)
In constant voltage mode, the power supply maintains the output voltage at the
selected value (V
SET
) while the load current I
L
varies with the load requirements.
Constant Current Mode Operation The power supply will operate in constant
current mode whenever the load resistance is low enough that the load current I L is
equal to the current limit setting I
SET
(Note: V
L
=I
SET
R
L
)
In constant current mode, the power supply maintains the output current at the
selected value (I
SET
) while the load voltage varies with the load requirements.
Automatic Mode Crossover This feature allows the power supply to
automatically switch operating modes in response to changing load requirements. If,
for instance, the power supply was operating in Constant Voltage Mode (I
L < I
SET
),
and the load changed so that the load current (I
L
) became equal to the current limit
setting (I
SET
), the power supply would automatically switch into Constant Current
Mode and the output voltage would vary in response to changes in load current. If
the additional load was subsequently removed so that the load current was again less
than the current limit setting, the supply would automatically return to Constant
Voltage Mode.
Output
Voltage
Constant Voltage
Mode Region
V
SET
0
0 I
SET
Output
Current
R
L
V
SET
I
SET
Crossover Point R
L
V
SET
I
SET
R
L
V
SET
I
SET
Constant Current
Mode Region
Where
R
L
V
SET
I
SET
Load Resistance
Output Voltage Setting
Output Current Limit Setting