[Amps] Plate transformer current unknown
Angelo Karabetsos
ve3yn at hotmail.com
Thu May 5 23:11:42 EDT 2005
Thanks Gary, Will and all for answering my questions. You learn a thing or
two everyday.
Cheers Angelo
<br><br><br>>From: Gary Schafer
<garyschafer at comcast.net><br>>Reply-To:
garyschafer at comcast.net<br>>To: Angelo Karabetsos
<ve3yn at hotmail.com><br>>CC: amps at contesting.com<br>>Subject: Re:
[Amps] Plate transformer current unknown<br>>Date: Tue, 03 May 2005
11:45:41 -0400<br>><br>>Hi Angelo,<br>><br>>.9 is about what you
get with a choke input filter.<br>>With a full wave bridge capacitor
input the no load voltage will be <br>>1.414 times. I usually use about
1.25 figure for loaded voltage when <br>>figuring supply output voltage.
It will of course vary depending on <br>>how good the transformer is. But
it gets you in the ball park.<br>><br>>For a doubler I figure around
2.5 times for loaded voltage.<br>><br>>73<br>>Gary
K4FMX<br>><br>>Angelo Karabetsos wrote:<br>>>I am unable to
calculate anything to do with windings or core due <br>>>to the fact
it is in a metal case encapsulated in black epoxy. I <br>>>discovered
this after removing the lid. I'll say one thing, it's <br>>>darn heavy
and hard to move around without anywhere to grab. The <br>>>secondary
wire gauge looks to be about 18ga and the dimensions are
<br>>>11"x9"x10" and has a RCA nameplate. Not too much
more information I <br>>>can determine. Now I know what to look for at
flea markets.<br>>>One other question. What should the B+ voltage be
after <br>>>rectification. Lets say 3000v secondary through a fullwave
bridge <br>>>rectifier and a bank of ten 470uf 450v caps? I read
somewhere to <br>>>multiply by 0.9 and that should be a good rule of
thumb. What I am <br>>>trying to determine is how to calculate the
proper transformer for <br>>>the job and keep voltage drop under load
to respectable figure. Not <br>>>an easy task to figure out with
surplus
parts.<br>>><br>>>Angelo<br>>><br>>>&gt;From:
&quot;Will Matney&quot;
&lt;craxd1 at ezwv.com&gt;<br>>>&gt;Reply-To:
craxd1 at ezwv.com<br>>>&gt;To:
amps at contesting.com<br>>>&gt;Subject: Re: [Amps] Plate transformer
current unknown<br>>>&gt;Date: Fri, 29 Apr 2005 11:28:25
-0400<br>>>&gt;<br>>>&gt;Angelo,<br>>>&gt;<br>>>&gt;Really
you cant tell that way (using the resistance) unless you <br>>>know
the mean lenght of turn, how many turns per layer, and how <br>>>many
layers they are in the winding. This then would give you how
<br>>>long the wire is and you could then use the resistance and the
<br>>>length to determine the wire size. If it's possible to use a
<br>>>micrometer or a wire gauge to see what the secondary wire size
is, <br>>>then one can find out what its rating is. In amateur
service, ICAS <br>>>used anywhere from 700 to 900 circular mils per
ampere. CCS uses <br>>>anyhwere from say 1000 to 1200 cir. mil. per
amp. If you can find <br>>>the wire size, go look at a wire chart for
how many circular mils <br>>>it has and divide by the above numbers to
determine its current <br>>>carrying ability. IE, 10,000 circular mils
running at 1000 cir mil <br>>>per amp = 10
amperes.<br>>>&gt;<br>>>&gt;Best,<br>>>&gt;<br>>>&gt;Will<br>>>&gt;<br>>>&gt;<br>>>&gt;***********
REPLY SEPARATOR ***********<br>>>&gt;<br>>>&gt;On
4/29/05 at 3:01 PM Angelo Karabetsos
wrote:<br>>>&gt;<br>>>&gt; &gt;I would like to find
out the current rating of a <br>>>transformer.
Primary<br>>>&gt; &gt;voltage taps 0v-110v-115v-208v-230v and
secondary taps <br>>>3450v-0v-3450v and<br>>>&gt;
&gt;secondary resistance of 53.5ohms from 0v to 3450v tap and
<br>>>107ohms from<br>>>&gt;
&gt;3450v<br>>>&gt; &gt;to 3450v tap. All measurements
done with a simple DMM. The <br>>>commercial<br>>>&gt;
&gt;amplifier it came out of has a plate current meter with a
<br>>>max reading of<br>>>&gt; &gt;600ma. How could I
find out the CCS or ICAS rating?<br>>>&gt; &gt;Cheers
Angelo<br>>>&gt; &gt;<br>>>&gt;
<br>>>&gt;_________________________________________________________________<br>>>&gt;
&gt;Take charge with a pop-up guard built on patented
<br>>>Microsoft® SmartScreen<br>>>&gt;
&gt;Technology<br>>>&gt;
<br>>>&gt;http://join.msn.com/?pgmarket=en-ca&amp;page=byoa/prem&amp;xAPID=1994&amp;DI=1034&amp;SU=http://hotmail.com/enca&amp;HL=Market_MSNIS_Taglines<br>>><br>>>&gt;
&gt; Start enjoying all the benefits of MSN® Premium right
<br>>>now and get the<br>>>&gt; &gt;first two months
FREE*.<br>>>&gt; &gt;<br>>>&gt;
&gt;<br>>>&gt;
&gt;_______________________________________________<br>>>&gt;
&gt;Amps mailing list<br>>>&gt;
&gt;Amps at contesting.com<br>>>&gt;
&gt;http://lists.contesting.com/mailman/listinfo/amps<br>>>&gt;<br>>>&gt;<br>>>&gt;<br>>>&gt;_______________________________________________<br>>>&gt;Amps
mailing
list<br>>>&gt;Amps at contesting.com<br>>>&gt;http://lists.contesting.com/mailman/listinfo/amps<br>>><br>>>_________________________________________________________________<br>>>Don't
just Search. Find! <br>>>http://search.sympatico.msn.ca/default.aspx
The new MSN Search! <br>>>Check it
out!<br>>><br>>><br>>>------------------------------------------------------------------------<br>>><br>>>_______________________________________________<br>>>Amps
mailing
list<br>>>Amps at contesting.com<br>>>http://lists.contesting.com/mailman/listinfo/amps<br>><br>><br>><br>
_________________________________________________________________
Take advantage of powerful junk e-mail filters built on patented Microsoft®
SmartScreen Technology.
http://join.msn.com/?pgmarket=en-ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Market_MSNIS_Taglines
Start enjoying all the benefits of MSN® Premium right now and get the
first two months FREE*.
More information about the Amps
mailing list