**Q.** Two shunt wound generators running in parallel supply a total load current of 4000 A. Each generator has an armature resistance of 0.02? and a field of 40?. The fiels are excited so that the emf induced in one generator is 480 V and in another 490 V, find the bus - bar voltage and kilowatt output of each machine.

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**Sol. ** V = bus bar voltage

I_{1} = current output of generator 1

I_{2} = current output of generator 2

I_{1} + I_{2} = 4000

I_{sh} = V/R_{sh}

Bus - bar voltage

In each machine

Bus bar voltage + voltage

Drop in armature = EMF generated

for generated 1, E_{1} = V + I_{a1} R_{a}

480 = V + (I_{1} + V/40) × 0.02

(I_{a1} = I_{1} + I_{sh})

for generated 2 490 = V + (I_{2} + V/40) × 0.02

Subtrating both with each other we get,

0.021_{2} - 0.021_{1} = 10

or I_{2} - I_{1} = 500

or (4000 - I_{1}) - I_{1} = 500

I_{1} = 1750A and I_{2} = 4000 - 1750 = 2250A

Now 480 = V + (I_{1} + V/40) × 0.02 or 490 = V + (I_{2} + V/40) × 0.02

On solving V = 444.8 volts

Kilowatt output

kW output of gen. 1, VI_{1}/1000 = 444.8 × 1750/1000 = 778.4kW

kW output of gen. 2, VI_{1}/1000 = 444.8 × 2250/1000 = 1001kW