Voltage Regulators
VOLTAGE REGULATORS
VOLTAGE REGULATORS
Because the voltage from an AC generator varies as the output load and power
factor change, a voltage regulator circuit is necessary to permit continuity of the
desired output voltage.
EO 1.1
STATE the purpose for voltage regulation equipment.
EO 1.2
Given a block diagram of a typical voltage regulator,
DESCRIBE the function of each of the following
components:
a.
Sensing circuit
b.
Reference circuit
c.
Comparison circuit
d.
Amplification circuit(s)
e.
Signal output circuit
f.
Feedback circuit
Purpose
The purpose of a voltage regulator is to maintain the output voltage of a generator at a desired
value. As load on an AC generator changes, the voltage will also tend to change. The main
reason for this change in voltage is the change in the voltage drop across the armature winding
caused by a change in load current. In an AC generator, there is an IR drop and an IXL drop
caused by the AC current flowing through the resistance and inductance of the windings. The
IR drop is dependent on the amount of the load change only. The IXL drop is dependent on not
only the load change, but also the power factor of the circuit. Therefore, the output voltage of
an AC generator varies with both changes in load (i.e., current) and changes in power factor.
Because of changes in voltage, due to changes in load and changes in power factor, AC
generators require some auxiliary means of regulating output voltage.
Block Diagram Description
Figure 1 shows a typical block diagram of an AC generator voltage regulator. This regulator
consists of six basic circuits that together regulate the output voltage of an AC generator from
no-load to full-load.
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