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Wave-wound shunt generator, power absorbed by load

Short answer

Generated emf E = (0.02×378×1000×4)/(60×2) = 252 V. Load and field in parallel with armature yield equivalent resistance 9.091 Ω. Armature current 24.973 A, terminal voltage 227.03 V. Load power = (227.03)²/10 = 5154 W.

A 4 pole d.c shunt generator with a field resistance of 100 Ω100\ \Omega and an armature resistance of 1 Ω1\ \Omega has 378 wave connected conductors in its armature. The flux per pole is 0.02 Wb. If a total resistance of 10 Ω10\ \Omega is connected across the armature terminals and the generator is driven at 1000 rpm. Calculate the power absorbed by the load.

The load (10 Ω) and the field winding (100 Ω) are both across the armature terminals, so they are in parallel. The generated emf comes from the emf equation for a wave winding (A=2A = 2).

Step 1: Generated emf

E=ΦZNP60A=0.02×378×1000×460×2=252 VE = \frac{\Phi Z N P}{60A} = \frac{0.02\times 378\times 1000\times 4}{60\times 2} = 252\ \text{V}

Step 2: Terminal resistance and armature current

Load in parallel with field:

Rp=100×10100+10=9.091 ΩR_p = \frac{100\times 10}{100 + 10} = 9.091\ \Omega Ia=ERa+Rp=2521+9.091=24.973 AI_a = \frac{E}{R_a + R_p} = \frac{252}{1 + 9.091} = 24.973\ \text{A}

Step 3: Terminal voltage

V=IaRp=(24.973)(9.091)=227.03 VV = I_aR_p = (24.973)(9.091) = 227.03\ \text{V}

Step 4: Load current and power

IL=V10=22.703 A,If=V100=2.270 AI_L = \frac{V}{10} = 22.703\ \text{A}, \qquad I_f = \frac{V}{100} = 2.270\ \text{A}

(Check: IL+If=24.973 A=IaI_L + I_f = 24.973\ \text{A} = I_a.)

Pload=V2RL=(227.03)210=5154 WP_{load} = \frac{V^2}{R_L} = \frac{(227.03)^2}{10} = 5154\ \text{W}

Answer: power absorbed by the load ≈5154 W\approx 5154\ \text{W} (≈5.15\approx 5.15 kW) at a terminal voltage of 227.03 V227.03\ \text{V}.

✓ Answer checked by Claude Opus 5.5 (high effort)

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