Calculating AC Generator Frequency

The frequency of the alternating current (AC) generated by an AC generator depends on two main factors: the number of poles in the generator and the speed at which the rotor rotates.

In this question, we are given:

• Number of poles (P) = 10
• Speed of rotation (N) = 1200 Revolutions Per Minute (rpm)

We need to find the frequency of the generated AC.

Key Formula for AC Frequency

The relationship between the frequency (f), the number of poles (P), and the speed of rotation (N) is given by the formula:

\(f = \frac{P \times N}{120}\)

Where:

• \(f\) is the frequency in Hertz (Hz)
• \(P\) is the total number of poles
• \(N\) is the speed of rotation in Revolutions Per Minute (rpm)

Step-by-Step Frequency Calculation

Let's plug in the given values into the formula:

\(f = \frac{10 \times 1200}{120}\)

First, multiply the number of poles by the speed:

\(10 \times 1200 = 12000\)

Now, divide this result by 120:

\(f = \frac{12000}{120}\)

\(f = 100\)

So, the frequency of the generated AC is 100 Hz.

Understanding the Result

A generator with 10 poles rotating at 1200 rpm will produce an AC voltage that completes 100 cycles every second. This is the frequency of the generated AC power.

Let's look at the options provided:

• 120 Hz
• 110 Hz
• 100 Hz
• 50 Hz

Our calculated frequency of 100 Hz matches one of the options.