Question

If induction motor air gap power is 10 KW and mechanically developed power is 8 KW, then rotor ohmic loss will be _________ KW.

(a) 1

(b) 2

(c) 3

(d) 4

This question was posed to me in examination.

My doubt is from Speed Control of Shunt or Separately Excited Motors topic in division Speed Control of Direct Current Motors & Induction Motors of Electric Drives

Answer 1

The relationship between air gap power, mechanically developed power, and rotor ohmic loss in an induction motor can be described by the equation:

$$\text{Air gap power}=\text{Mechanically developed power}+\text{Rotor ohmic loss}$$

Given:

• Air gap power = 10 kW
• Mechanically developed power = 8 kW

We can calculate the rotor ohmic loss as:

$$\text{Rotor ohmic loss}=\text{Air gap power}-\text{Mechanically developed power}$$ $$\text{Rotor ohmic loss}=10\text{kW}-8\text{kW}=2\text{kW}$$

Thus, the rotor ohmic loss is 2 kW.

The correct answer is (b) 2.