Question

What is the input current of a 2 hp single phase motor, 240 V at 70 % efficiency and 0.8 power factor? 

a. DOL starter

b. Rotor resistance starter

c. Autotransformer starter

d. All of these

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Answer 1

Answer:

D is a right answer so much

Answer 2

The input current is 11.1 A.

Given that,

Output power rating of single phase Induction motor = 2HP                      

                                                                                         = 2 x 746W

                                                                                         = 1492 W.

Supply voltage (V) = 240V

Efficiency = 70% = 0.7

Power factor = 0.8

We know that, $efficiency =$ $\frac{O/P}{I/P}$ ,

where O/P is output power and I/P is input power

    Input power, I/P =  $\frac{O/P}{efficiency}$

                                = $\frac{1492}{0.7}$

                                = 2131.43 W

Now, P = V x I x power factor

2131.43 = 240 x I x 0.8

⇒        I = $\frac{2131.43}{240 * 0.8}$

             = 11.1 A

Thus the input current is 11.1 A.

• The quantity of energy put into a device is referred to as input, and the amount of energy that comes out is referred to as output.
• The type of energy can be altered by a technology, but not its quantity.
• For instance, a light bulb uses electrical energy as its input energy and produces light and heat as its output energy.

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