[Lowfer] A power supply head scratcher

[Jordan]

You're going to start a fire....


----- Original Message ----- 
From: "Bill Ashlock" <ashlockw at hotmail.com>
To: <lowfer at mailman.qth.net>
Sent: Saturday, April 17, 2010 5:27 PM
Subject: Re: [Lowfer] A power supply head scratcher



"I simply connected them 10 volt positive open, and the negative
 connected to the 24 volt positive, with the negative open."

Hi Andy,

Am I correct in my thinking that you have not connected anything to one of 
the two output wires of each wallwart? If so, I don't understand why this 
works at all unless there is some kind of sneak path to the neutral line in 
each power supply. Why not connect them in series as though they are 
batteries? These wallwarts have a power transformer that should isolate the 
DC output from their AC power inputs and this DC should float relative to 
anything else.

Bill

> Date: Fri, 16 Apr 2010 20:38:58 -0700
> From: ku4xr at yahoo.com
> To: lowfer at mailman.qth.net; part15 at yahoogroups.com
> Subject: [Lowfer] A power supply head scratcher
>
> First, Thanks for all the responses to the antenna insulator question.
> J.B. had the one i'd never of thought up, The broken pole vault pole.
>
> I do have a head scratcher here. To get around 35 volts DC, I have
> connected 2 wallwarts in series. One is a 10 volt, and the other,
> a 24 volt. Connected together I have 37 volts DC. *** This is the first
> time I have ever tried this method before, so I have no previous
> experience to go by. I simply connected them 10 volt positive open, and
> the negative connected to the 24 volt positive, with the negative open.
> The problem I'm having is that everytime something in the house turns
> OFF, it kicks off the beacon....hmmmm. AC goes off, and so does the
> beacon, fan in the room goes off, beacon does too. connect the HF ant.
> to the radio and it kicks the beacon off. I have filtered the hound out
> of it. But can't stop this problem. It seems to be coming in on the
> ground line. These 2 wallwarts were 2 pronged plugs, and would not work
> the circuit until I connected a 3 prong plug with the ground wire going
> to the DC negative wire. The warts are SMPS. Even though I have the
> voltage I want, something is amiss. It is getting spiked somehow.
> Has anyone tried this before, and had a similar experience ?? If so,
> were you able to fix it, and how did you do it ?? I may have something
> wired the wrong way, or maybe missing a capacitor where one should be.
> I don't have a schematic for a circuit like this, and can't find one
> on the net. I'm wondering if I have a floating ground issue between the
> 2 wallwarts.
> Any input will be appreciated, and thanks for your time.
>
> 73 everyone :::
>
>
> Andy - KU4XR - EM75xr - Friendsville, TN. USA
> LOWfer Beacon " XR " @ 185.29875 KHz ( QRSS-60 )
> Coordinates:  N:  35º 43' 54" - W:  84º 3' 16"
> http://www.myspace.com/beaconxr
> http://webpages.charter.net/ku4xr/
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