{Collins} Re: HV Choke for the KWS-1



There seems to be some capacitive coupling when the choke is placed the
negative lead that slightly reduces its effectiveness.  However, it is only
a concern if you are making a power supply where there might be a concern
about reducing ripple to the lowest level possible.  I don't know about the
newer ARRL handbooks but it is discussed in the older issues.

For HV power supplies, it is perfectly acceptable to place the choke in the
negative lead.

David C. Hallam
KC2JD

-----Original Message-----
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[mailto:collins-bounce@xxxxxxxxxxxxxxxxxxxxx]On Behalf Of
lorenzenenterprises@xxxxxxxx
Sent: Wednesday, February 02, 2005 7:25 PM
To: entropy@xxxxxxxxxxx
Cc: relichuntercw@xxxxxxxxx; collins@xxxxxxxxxxxxx
Subject: {Collins} Re: HV Choke for the KWS-1


Ripple current through the choke same whether it is in positive lead or
negative.  Capacitance to ground is same whether choke is in plus or minus
lead.  and, capacitance concern when cycles are 120 ??
what?

note that when the choke is in negative lead, need to pay attention to
citcuit details such as connection of filter capacitors negative lead.

Richard Lorenzen  cca member


-- <entropy@xxxxxxxxxxx> wrote:
For HH and the list:

Hello!

   I read your note on choke placement and it reminded me of something that
I read somewhere long ago.

   As I recall, it is perfectly reasonable to place the choke in the center
tap of the plate transformer and thus bring it closer to ground potential.
The choke is a current device, is essentially in series with the supply
output, and works equally well as a choke whether it is in the positive or
negative leg of the supply.

   The drawback to this configuration is that some of the ripple current
will be capacitively coupled around the choke to ground by means of
inter-winding capacity and capacity from the windings to the frame of the
choke.   This reduces the effectiveness of the choke.   How much hum will be
added to any given supply would have to be determined empirically, I should
think, but probably won't be much.

73,
Jim T.
KB6GM
entropy@xxxxxxxxxxx


----- Original Message -----
From: "H H" <relichuntercw@xxxxxxxxx>
To: "Paul Katz" <pkatz@xxxxxxxxxx>
Cc: "Collins Listserve" <collins@xxxxxxxxxxxxx>
Sent: Sunday, January 30, 2005 10:40 AM
Subject: {Collins} Re: HV Choke for the KWS-1


> Hi Paul, .. This I have noticed on several supplies I
> have worked on. Since Collins didn't do it in the
> first place I am curious as to what the draw backs
> might be. The choke would definately be at a lower
> impedance position in the center tap of the supply and
> would seem to perform the same function. I was just
> curious as to what some of the other old heads
> thought. .. Hop

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