Question

The armature resistance of a 6 pole lap wound d.c machine is 0.05 ohms . If the armature is
rewound using a wave winding, then the armature resistance will be​

Answer 1

Answer:

hope this may help

Answer 2

Answer:

The armature resistance will be equal to 0.45Ω.

Explanation:

There is two types of armature winding of a D.C. machine:

• Lap Binding: $(I_{a})_{L}=A(I_{p})$    and $A=P$

        where $(I_{a})_{L}$ is current in lap binding

                   $I_{p}$ is current in parallel path

                 $A$ is number of parallel path

         Given : The number of poles is $P=6$   ∴ $A=6$

• Wave Bonding:    $(I_{a})_{w}=2(I_{p})$   and $A=2$

        $(I_{a})_{w}$  is armature current in wave binding

From the theorem of power conservation:

$(P)_{L}=(P)_{w}$

$(I_{a})^{2}_{L}(R_{a})_{L}=(I_{a})^{2}_{w}(R_{a})_{w}$

$(6I_{p})^{2}_{L}(0.05)=(2I_{p})^{2}(R_{a})_{w}$

$(R_{a})_{w}=9*0.05$

$(R_{a})_{w}=0.45$Ω