Spacecraft Shielding

http://www.dartmouth.edu/~sshepherd/research/Shielding/
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Pretty good review of problem, Ole.

Warren,

To paraphrase Ole's answer, your pretty much not going to smoke it with
higher frequencies, the lower ones where the cores hits saturation at a
lower voltage is another story as fully saturated there will be no
magnetic reactance on the primary wingdings and it begins to look like a
short hence the cooked winding's.   You will only notice efficiency
drops depending on the transformer, a little or a lot.

So if you take a 60Hz to 30hz feed it half the voltage.  Probably best
to be safe not to go below 50 Hz but 400 should not be an issue aside
from poss lower efficiency.

I use torroids for some home made electrostats and it's surprising how
flat the frequency response is out of these but I have the crossed over
at no lower than 80Hz so already higher than intended use anyways.  I
have cooked a few though too.

On 3/3/2019 9:52 AM, Warren Keillor [email protected]
[EVGRAY] wrote:
>  
>
> Norm and all
>
> Does anyone have a ball park idea of the frequency tolerance of a 60
> hz transformer doing other frequencies? How far can one stretch a 60
> hz transformer before it smokes? Like 25hz to 400hz?
> Cheers Warren
>
> Sent from Yahoo Mail on Android
> <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
>
>     On Sun, 3 Mar 2019 at 7:07 AM, Norman Wootan [email protected] [EVGRAY]
>     <[email protected]> wrote:
>      
>
>     http://www.dartmouth.edu/~sshepherd/research/Shielding/
>
>
>     Sent from Yahoo Mail on Android
>     <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
>
>     Pretty good review of problem, Ole.
>
>

Norm and allDoes anyone have a ball park idea of the frequency tolerance of a 60 hz transformer doing other frequencies? How far can one stretch a 60 hz transformer before it smokes? Like 25hz to 400hz?Cheers Warren

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  On Sun, 3 Mar 2019 at 7:07 AM, Norman Wootan [email protected] [EVGRAY]<[email protected]> wrote:       

http://www.dartmouth.edu/~sshepherd/research/Shielding/
Sent from Yahoo Mail on Android
Pretty good review of problem, Ole.  #yiv8466040451 #yiv8466040451 -- #yiv8466040451ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv8466040451 #yiv8466040451ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv8466040451 #yiv8466040451ygrp-mkp #yiv8466040451hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv8466040451 #yiv8466040451ygrp-mkp #yiv8466040451ads {margin-bottom:10px;}#yiv8466040451 #yiv8466040451ygrp-mkp .yiv8466040451ad {padding:0 0;}#yiv8466040451 #yiv8466040451ygrp-mkp .yiv8466040451ad p {margin:0;}#yiv8466040451 #yiv8466040451ygrp-mkp .yiv8466040451ad a {color:#0000ff;text-decoration:none;}#yiv8466040451 #yiv8466040451ygrp-sponsor #yiv8466040451ygrp-lc {font-family:Arial;}#yiv8466040451 #yiv8466040451ygrp-sponsor #yiv8466040451ygrp-lc #yiv8466040451hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv8466040451 #yiv8466040451ygrp-sponsor #yiv8466040451ygrp-lc .yiv8466040451ad 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Hi Warren,

The inductive reactance of the no load transformer is increasing proportionally with the frequency as this is actually just an inductor (i.e. there is only current through the primary coil when the secondary is open circuited). This means that to fully magnetize the core at double the designed frequency the input voltage must be doubled too. At half the frequency the primary voltage then must be halved to prevent saturating the core as the no load current is doubled. Another problem at higher frequency is the resistive loss from eddy currents in the core. To minimize this loss thinner lamination sheets are needed or a less electrical conductive magnetic conductor for the core material.

Regards
Ole
 

---In [email protected], <schoonersolsticemoon@...> wrote :

 Norm and all Does anyone have a ball park idea of the frequency tolerance of a 60 hz transformer doing other frequencies? How far can one stretch a 60 hz transformer before it smokes? Like 25hz to 400hz?
 Cheers Warren

 Sent from Yahoo Mail on Android https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature
 
 On Sun, 3 Mar 2019 at 7:07 AM, Norman Wootan nwootan@... [EVGRAY]
 <[email protected]> wrote:

   
 http://www.dartmouth.edu/ http://www.dartmouth.edu/~sshepherd/research/Shielding/
 Sent from Yahoo Mail on Android https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature
 

 Pretty good review of problem, Ole.