Lodestar LS1130 Instruction Manual - Setting Current Limit
12
Setting Current Limit
1) Determine the maximum safe current for the device to be powered.
2) Temporarily short the (+) and (-) terminals of the power supply together with a
test lead.
3) Rotate the COARSE VOLTAGE control away from zero sufficiently for the C.C.
indicator to light.
4) Adjust the COARSE and FINE CURRENT control for the desired current limit.
Read the current value on the LED display.
6) Remove the short between the (+) and (-) terminals and hook up for constant
voltage operation.
The current limit (overload protection) has now been preset. Do not change the
CURRENT control setting after this step.
5.4 Typical Constant Current Operation
1) Before connecting the device to be powered to the power supply, determine the
maximum safe voltage to be applied and set the VOLTAGE controls to obtain that
voltage reading on the LED display.
2) Determine the desired constant current value. Set the COARSE and FINE
CURRENT control to minimum (fully counterclockwise).
3) Turn off the power supply and connect it to the device to be powered.
4) Turn on the power supply.
5) Increase the COARSE and FINE CURRENT control setting until the desired
constant current value is read on the display, or set the current limit in advance
(before connecting the load) as prescribed earlier in the “Setting Current Limit”
procedure.
If the load current drops below the constant current value, the CC indicator will go off
and the CV indicator will light. In this case, the power supply automatically switches
to the constant voltage mode, and further rotation of the CURRENT controls will not
increase the output current.
Constant Voltage/Constant Current Characteristic
The working characteristic of this power supply is called a constant voltage/constant
current automatic crossover type. This permits continuous transition from constant
current to constant voltage modes in response to the load change. The intersection of
constant voltage and constant current modes is called the crossover point. The figure
below shows the relationship between this crossover point and the load.