User manual

LABKON Series
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GMC-I Messtechnik GmbH 53
5.9 Considerations
During the operation of the power supply, various problems may occur because of the difference in connected loads, which
will be introduced as follow respectively.
5.10 Capacitive Load
In most cases, the power supply will be stable for capacitive loads of any size. Loads with large capacitor may cause ringing
in the power supply’s transient response. It is possible that certain combinations of loads will result in output instability. And
the problem may be solved by properly decreasing the total load capacitance.
A large capacitor at the output terminals may cause the power supply to cross into CC or unregulated mode momentarily
when the output is enabled. The slew rate of the output voltage will be limited to the current setting divided by the total load
capacitance (internal and external).
Signal
Internal
Capacitance
Internal
Load Current
Slew Rate at No Load and
Full Scale Current Setting
LABKON P500 35 V 14.5 A
3000 µF
0.65A
2 V/msec
LABKON P500 80 V / 6.5 A
1440 µF
0.3A
4 V/msec
LABKON P500 120 V / 4.2 A
660 µF
0.15A
6 V/msec
LABKON P800 35 V 22.5 A
3000 µF
0.65A
2 V/msec
LABKON P800 80 V 10 A
1440 µF
0.3A
4 V/msec
LABKON P800 120 V 6.5 A
660 µF
0.15A
6 V/msec
5.11 Inductive Load
Inductive loads present no loop instability in constant voltage mode. In constant current mode, inductive loads form a parallel
resonance with the power supply’s output capacitor. Generally this will not affect the stability of the power supply, but it may
cause ringing instantaneously when the power supply responds to the output..