Home » Audio » Group Build » minimizing Cw and evaluating tradeoffs....
minimizing Cw and evaluating tradeoffs.... [message #31606] Wed, 14 December 2005 22:41 Go to next message
MQracing is currently offline  MQracing
Messages: 220
Registered: May 2009
Master
Here is a quick example to consider regarding tradeoffs and designing for one parameter.

Transformer A

EI 100 x 1" stack

6000 turns of #32 wire

calc self capacitance of 133.1 pf

calc L of 681.49 henries

calc L sub l of .658 henries

calc flux density at 60vrms and 20 hz = 1938 gauss

dcr of 456 ohms


Transformer B

EI 50 by 1/2" stack

6000 turns of #40

calc self capacitance of 14.8 pf

calc L of 269 henries

calc L sub l of 1.62 henries

calc flux density at 60vrms at 20 hz = 7753 gauss

dcr of 1581 ohms


the above examples assume use of M6 core material in each case.


so... what do we have? If we pick on the basis of which unit has the lowest winding capacitance then surely transformer B wins hands down... it has only 11 percent of the calc self capacitance of transformer A.

But what did we pay to cut out nearly 90 percent of the capacitance of transformer A?

Our winner has only about 39 percent of the inductance of transformer A.

Our winner has 246 percent more leakage inductance than transformer A.

Our winner operates at 400 percent higher flux density level than transformer A.

Our winner has 347 percent more winding resistance (dcr) than transformer A.


Is transformer B really the winner just because it has less winding self capacitance than transformer A?

Were they good trade offs?

msl



Re: minimizing Cw and evaluating tradeoffs.... [message #31607 is a reply to message #31606] Thu, 15 December 2005 04:20 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
thanks for the example. You leaped from measure one parameter to design for one parameter. Two *VERY* difrerent things.

BTW, it was measure the results of several parameters, and their interaction surrounding one of the quantities of interest.
cheers,
Douglas


and BTW... [message #31608 is a reply to message #31606] Thu, 15 December 2005 10:16 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
I am so glad to hear we're 'Old Friends' and that you're working with me on the Cw issue. So glad to hear it...
cheers,
Douglas

Re: and BTW... [message #31609 is a reply to message #31608] Thu, 15 December 2005 12:53 Go to previous messageGo to next message
Damir is currently offline  Damir
Messages: 1005
Registered: May 2009
Illuminati (2nd Degree)
That`s the Christmas spirit! No Scroodges on this forum!

Re: and BTW... [message #31610 is a reply to message #31609] Thu, 15 December 2005 13:13 Go to previous messageGo to next message
MQracing is currently offline  MQracing
Messages: 220
Registered: May 2009
Master
geez... I didn't look behind me... was that jolly ole Saint Peter tugging on my coattails?

happy hollidays,

msl

nope... [message #31611 is a reply to message #31610] Thu, 15 December 2005 13:53 Go to previous message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
just quoting you.
cheers,
Douglas

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