# Negative voltage regulation of the alternator is indicative that the load is

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Negative voltage regulation of the alternator is indicative that the load is
1. capacitive only
2. inductive only
3. inductive or resistance
4. none of the above

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Correct Answer - Option 1 : capacitive only

Voltage regulation: The voltage regulation of an AC alternator is,

Percentage voltage regulation $= \frac{{{E_{g0}} - {V_t}}}{{{V_t}}} \times 100$

Eg0 is the internally generated voltage per phase at no load

Vt is the terminal voltage per phase at full load

Voltage regulation indicates the drop in voltage from no load to the full load.

There are three causes of voltage drop in the alternator.

• Armature circuit voltage drop
• Armature reactance
• Armature reaction

The first two factors always tend to reduce the generated voltage, the third factor may tend to increase or decrease the generated voltage. The nature of the load affects the voltage regulation of the alternator.

Important Points:

• At unity and lagging power factor loads, the terminal voltage is always less than the induced EMF and the voltage regulation is positive.
• At higher leading loads, the terminal voltage is greater than the induced EMF and the voltage regulation is negative.
• The lower the leading power factor, the greater the voltage rise from no load (Eg0) to full load (Vt)
• The lower the lagging power factor, the greater the voltage decrease from no load (Eg0) to full load (Vt)