How to calculate the resistance of a lap wound armature?

[Neil Hayes]

Homework Statement

A 4 pole lap wound armature has 16 coils, each with a resistance of 0.1 ohms. Calculate the resistance of the armature?

Homework Equations

The Attempt at a Solution

Hi there fellow members,

I'm currently doing a section of my course which deals with Electrical machines. The lesson that I am on at the moment is dealing with Armature windings ( lap and wave ).

There are two diagrams in the lesson but they are confusing.

One leads me to think that the total resistance would be 16*.01 ='s 1.6 ohms

The other one leads me to think that there are 4 parallel paths. 4*4 = 16

4*0.1=0.4 so total resistance is

1/R = (1/0.4)*4

R = 1/10

R = 0.1 ohms

With the fact that it's a question being asked I would think that the 1.6 is a bit straight forward so I'm leaning towards the 0.1 ohms answer.

Any help/suggestions would be greatly appreciated :)

Neil

P.S Thanks for taking the time to read the question!

 

[cnh1995]

The other one leads me to think that there are 4 parallel paths. 4*4 = 16

4*0.1=0.4 so total resistance is

1/R = (1/0.4)*4

R = 1/10

R = 0.1 ohms

That's correct.

 

[Neil Hayes]

That's correct.

Thanks cnh1995 :)

Do you mind if I ask why we have 4 parallel paths? Is this standard for a 4 pole lap wound armature? Having the answer is good but understanding why is the best thing and my lesson notes are fairly unclear, to say the least!