A single-phase ac switch is used in between a 230 V source and load of 2 kW and 0.8 lagging power factor. Determine the rms current rating required by the SCR. Use the factor of safety = 2.

To determine the RMS current rating required by the SCR, we first need to calculate the load current using the given voltage, power, and power factor.

1. Calculate the real power (P):

[

P = 2000 , text{W} = 2 , text{kW}

]

2. Calculate the apparent power (S):

[

S = frac{P}{text{power factor}} = frac{2000 , text{W}}{0.8} = 2500 , text{VA}

]

3. Calculate the RMS current (I):

Using the relationship ( S = V times I ):

[

I = frac{S}{V} = frac{2500 , text{VA}}{230 , text{V}} approx 10.87 , text{A}

]

4. Apply the factor of safety:

[

I_{text{rated}} = I times text{factor of safety} = 10.87 , text{A} times 2 approx 21.74 , text{A}

]

Thus, the RMS current rating required by the SCR is approximately 21.74 A.