Question

an alternating current of frequency 50Hz
has a maximum value of 120A a) write down the equation for the current
b) calculate the average value,RMS value and form factor​

Answer 1

Answer:

(a) the equation for the current

$i(t) = 120 \: sin2\pi \: ft \\ f = 50 \: hz \: \\ i(t) = 120 \: sin(100\pi \: t)$

(b) RMS value

$i \: rms = \frac{120}{ \sqrt{2} } \\ = 60 \sqrt{2} =84.852$

If the maximum value of alternating current is “IMAX“, then the value of converted DC current through rectifier would be “0.637 IM” which is known as average value of the AC Sine wave (IAV).

$i \: avg = 0.637 \times 120 = 76.44$

The ratio between RMS value and Average value of an alternating quantity (Current or Voltage) is known as Form Factor.

$FF = \frac{84.852}{76.44} = 1.11$