Electrical Power Systems Technology

Direct Current Power Systems 199

sistance, but its AC impedance is much larger. It therefore passes DC and

blocks the AC component of the rectified voltage.

DC REGULATION METHODS

The concept of voltage regulation can best be understood by referring

to the formula:

VNL – VFL × 100

VR = ———————

VFL

where:

VR = the voltage regulation in percent,

VNL = the no-load (open-circuit) voltage, and

VFL the rated, full-load voltage.

Sample Problem:

Given: a power supply has a no-load voltage of 24.85 volts and a rated

full-load voltage of 24.0 volts.

Find: the voltage regulation of the power supply.

Solution:

VNL – VFL × 100

%VR = ———————

VFL

24.85 – 24.0 × 100

= ———————

24.0

= % VR = 3.5%

Figure 7-30. A pi-type filter circuit