[Prev][Next][Index][Thread]

k - Alternative Method

Hi everyone,
            I've had a request for the alternative method of setting
a system up for a particular k, so here it is. To anyone who has 
previously posted this method, my apologies for repeating their work
unbeknownst to myself.
     This method requires an accurate inductance meter.
Method :
(0) Make sure nothing is connected to either coil (e.g. ground).
(1) Measure the inductance of each coil separately.
(2) Decide on the k you wish to couple them at (the table listing 
    the number of half-cycle transfers may be used as a guide).
(3) From M = k x SQRT(Lp x Ls) calculate the Mr (mutual inductance
    required).
(4) Now, to find the M the system is currently set at :
    (a) Connect one end of the primary to the bottom of the secondary
        coil and measure the inductance of the two coils wired 
        together (ie one lead of the inductance meter goes to the top
        of the secondary and the other lead to the free lead of the 
        primary). Note the value as Lx.
    (b) Disconnect the primary again and connect the other end to the 
        bottom of the secondary. Measure the inductance of the two  
        coils again. Call this value Ly.
The mutual inductance the system is set at is : M = (Lx + Ly)/4
If Mr > M, the coils will have to be coupled tighter. If Mr < M,
the coupling will have to be loosened (goes without saying I suppose).
   After adjusting the system, remeasure Lx and Ly and recalculate M.
   There is probably a less tedious way of doing it but this will 
work, iterations notwithstanding.

(Extra info - this method is the series-aiding/opposing method. The
larger of Lx and Ly is the aiding value. Neither Lx nor Ly should
equal the individual coil inductances - one should be larger than Ls
and the other should be smaller).

Malcolm