A 12 -pole D C shunt generator has 50 slots on its armature with 12 conductors per slot with wave winding. The armature and field winding resistance is 0.5 ohm and 60 ohm respectively. The generator is supplying a resistive load of 15 ohm at terminal voltage of 300 V when running at a speed of 625

Question

A 12 -pole D C shunt generator has 50 slots on its armature with 12 conductors per slot with wave winding. The armature and field winding resistance is 0.5 ohm and 60 ohm respectively. The generator is supplying a resistive load of 15 ohm at terminal voltage of 300 V when running at a speed of 625 rpm. Find the armature current, the generated emf and the flux per pole.

Accepted Answer

The conventional diagram is shown in Fig. 4.61.

[latex]I_{L}=\frac{V}{R_{L}}=\frac{300}{15}=20 A[/latex]

[latex]I_{s h}=\frac{V}{R_{s h}}=\frac{300}{60}=5 A[/latex]

Armature current, [latex] \quad I_{a}=I_{L}+I_{s h}=20+5= 2 5 A[/latex]

Generated emf,

[latex]E_{g} =V+I_{a} R_{a} [/latex]

[latex]=300+25 imes 0.5= 3 1 2 . 5 V[/latex]

Now,

[latex]E_{g} =\frac{\phi Z N P}{60 A}[/latex]

where, [latex] Z=50 imes 12=600 ; N=625 rpm ; P =12 ; A =2[/latex];

[latex] herefore[/latex]

[latex] 312.5=\frac{f imes 600 imes 625 imes 12}{60 imes 2}[/latex]

or

[latex] \phi=8.33 m ext { Wb }[/latex]

Question 4.38: A 12 -pole D C shunt generator has 50 slots on its armature ...

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