I am reading R. Krishnan's book about Switched Reluctance Motor and i can't understand the following lines in choosing the number of turns,
The best values are those that would
satisfy the following mutually contradictory demands:
1. Small current implying a larger number of turns
2. Small values of resistance and inductance of the winding implying a
smaller number of turns
Can anyone please help in understanding what does he want to say we should consider choosing the number of turns?
Both statements are correct. For 1st statement as motor is designed for a specific working flue density, which could be achieved by the needed AT obtained for the used B-H curve., hence for the obtained H value in AT, if turns increases the needed current would be less and vice versa. For second statement as inpedance(Z) of winding, equal to Squar root of (Rsqr+Xlsqr) resistance sqr. plus reactance sqr. which could control the current flow from winding(I=V/Z), and resistance(R=((resistivity)(length))/A) and inductive reactance(Xl=2(Pai)fL), which would be less with less length or less number of turns(with increased current) as inductance could be define as variation of flux with the variation of current(L=do/di).
So both statements are giving the same meaning right ? so why does he call them mutually contradictory?
Noman,
I am adding a couple of points to clarify the doubt.
So #1 emerges from an electromagnetic requirement, while #2 emerges from an electric circuit (KVL) requirement. They are certainly not the same; and rather, of different origin !
Hope that helped.
-Sanjay
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