power!..pls answer...?

Question

A d.c. motor draws a current of 50A at 230V. If 200W is dissipated in the form of heat in the motor, how much power is available for mechanical work?

Answer 1

power is wattage, and is the product of voltage and amperage. Total drawn by the motor is

50A * 230V = 11,500W

Of that, 200 is wasted as heat, leaving 11,300W for mechanical work.

BTW, at 11,300/11,500 = 98%, this is a pretty damn efficient motor, especially for DC!

Answer 2

To calculate power in electronic circuits and devices such as the dc motor there's a couple of formula you can use. P = I^2R or P = IV.

In this case I would suggest P = IV since you know the amperage and the voltage being used by the motor. In electronics power is always measured in watts. So to solve the problem we will use the equation as follows.

Pt= (It)(Vt)

Total power = total current * total voltage

Pt = 50A * 230V

Pt = 11500 W

So now we subtract the 200 W that's dissipated as heat we get the amount of power available to do the mechanical work.

Pw = Pt - Ph

Work power = Total power - Power of heat dissipation

Pw = 11500 - 200

Pw = 11300 W Final answer

Answer 3

P = E x I

Since this is a D.C. circuit, there is no phase or power factor considerations, nor any inductive reactance. Therefore it's a straightforward equation.

E=230 and I=50, so P=11,500W

Since 200W is dissipated in the form of heat, the net power available for mechanical work is 11,500W - 200W = 11,300W

So your answer is 11,300W

Answer 4

230 x 50 = 11,500W - 200 = 11,300W