Hi to All
I'll have designed Power supply in many years mostly Switch mode Power and
in low power.
I decide to run some LT-spice simulation on it to find out what what the
best type ?
Design 4KV 1Amp and Vripple pp 100V, Transformer loss included
1. single phase with choke Eff app 96%
2 . 3 phase no choke Eff app 96%
3. single phase no choke Eff app 97%
This means 3 and 4 % out in heat out of the Box.
As far I can se, there is not any difference in what you are burning out in
heat !
another case is about Power company will like the choke version because the
crest factor.
Sense there is not big difference form the user this most be a question
about
Components prise/weight.
73 Boye OZ1CTK
----- Original Message -----
From: "Rob Atkinson" <ranchorobbo@gmail.com>
To: "Chris Wilson" <chris@chriswilson.tv>
Cc: "Amps" <amps@contesting.com>
Sent: Thursday, December 20, 2012 12:19 PM
Subject: Re: [Amps] Choke input filters, design criteria?
yes the Henrys used resonant choke filters. This helps explain it:
http://www.qsl.net/i0jx/supply.html
There was a nice article in QST in June 1946 about how to get the
inductance of a "mystery" choke using some math, a multimeter, an AC
microampere meter, and 120 v. service but since you have 240 you'd
have to work with one side of that if the UK has neutral return (four
wire service).
If you can get access to QST on-line: "How Much Inductance? A simple
method for measuring unknown filter chokes" by George H. Floyd W6OJK/2
June 1946 QST p. 69 and 132.
73
Rob
K5UJ
On Wed, Dec 19, 2012 at 8:14 AM, Chris Wilson <chris@chriswilson.tv>
wrote:
4 H is a bit low; 8 would be better. Choke input filters are good for
power supply loads that are fairly constant, i.e. modes like AM, FM,
and RTTY. Take a look at the designs used in earlier amps like the
Heathkit HA-10 as something to work off of, also the power supply
sections of 1 KW vacuum tube AM broadcast rigs. Don't forget old
handbooks, West Coast and ARRL from the '40s and '50s. if you are in
the UK perhaps RSGB has old handbooks with design criteria. You could
start with an 8 uF oil cap. Let's assume you are going with 3.5 KV.
Look for a cap rated for over 4; 4.5 KV or more is a good idea.
Follow that with the choke and another oil cap like the first one at
the input. Don't fool around with electrolytics that will need to be
replaced some day--this is a filter that will last as long as you do.
Use the ratings of the choke as your guide. Make sure the v. rating
of the caps is working volts DC. Stay away from energy discharge
caps--a genuine filter cap will be bigger with sizable insulators on
the contact lugs.
73
Rob
K5UJ
19/12/2012 14:03
Thanks for the reply Rob. Is there a way to check the inductance of
another choke I have? The other one is bigger, and is from a 3 phase
supply for a Henry RF Generator. It gave just under 5kV at 1.5 amps.
Henry use the same part number in both the 3 and single phase versions
of the HV supply, but the single phase version uses 2 off 0.1uF
resonating capacitors, and a 4uF filter cap, with fairly low value
bleeder resistors. I believe these are to keep off load voltage in
check? The Henry schematics show both supplies using the same part
number of choke, but the 3 phase uses no resonance caps. The
schematics don't give the inductance though.
I believe an HV choke needs measuring for inductance with DC on it,
for the purposes of use as a resonant choke, and making it resonant at
twice the mains frequency (100Hz in this case, after a full wave
bridge).
--
Best Regards,
Chris Wilson.
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