Peter:
Good explanation of why and how! Thanks.
However there seems nothing to "balance"!
- Jim WB6BLD
----- Original Message -----
From: "Peter" <peterNOSPAM@wires.ndo.co.uk>
To: "Jim Tonne" <tonne@comcast.net>
Cc: <craxd1@verizon.net>; <amps@contesting.com>
Sent: Thursday, June 01, 2006 4:36 PM
Subject: Re: [Amps] Series PC Power Supplies
> PSU manufacturers recommend adding these diodes when placing units in
> series. Major reason is that should one unit shut down and not be
> generating power the output rectifier and filter network becomes reverse
> driven by the remaining unit(s)
>
> Peter G3YYN
>
> Jim Tonne wrote:
>> Will:
>> If the supplies are in series wouldn't each be passing
>> the same number of amps? What is there to "balance"?
>> What do you mean by "placing rectifiers across..." each
>> supply?
>> - Jim WB6BLD
>>
>>
>> ----- Original Message -----
>> From: "Will Matney" <craxd1@verizon.net>
>> To: <amps@contesting.com>
>> Sent: Thursday, June 01, 2006 3:07 PM
>> Subject: Re: [Amps] Series PC Power Supplies
>>
>>
>>> Another recommended practice is to place rectifiers across the + and -
>>> of each supply to try and balance the load. If the load is not balanced
>>> across each, one supply can be overburdened if just slightly off from
>>> the others. The rectifiers need to be rated at the same current
>>> capability of the total supply in a series connection. The low side
>>> supplies ground will be the supply ground and the ground for the last
>>> rectifier in the string. This is shown in several power supply books
>>> that mentions seriesing and paralelling supplies for increased voltage
>>> or current. Generally though, this practice of using several supplies is
>>> not really recommended because of the balancing problems.
>>>
>>> Best,
>>>
>>> Will
>>>
>>>
>>> *********** REPLY SEPARATOR ***********
>>>
>>> On 6/1/06 at 11:57 AM Joe Isabella wrote:
>>>
>>>> Two things...
>>>>
>>>> 1. You can get a brand new 25A switching supply for $80-90 if you look
>>>> around. I bought my Samlex 25A for $80.
>>>>
>>>> 2. How did you series the supplies you have? The "first" one will
>>>> provide
>>>> your "ground" connection. Take the red wires from that and connect
>>>> them
>>>> to the black wires of the "second" supply. Now take the red wires from
>>>> that one, and connect them to the black wires of the "third" supply,
>>>> which
>>>> will provide the positive (15 VDC from the black wires of the "first"
>>>> supply to the red wires of the "third" supply, in this case) to your
>>>> rig.
>>>> Make sure you tied the orange wires to each supply's red wires so they
>>>> all
>>>> see "power good" line properly. Make sure you have isolated the black
>>>> leads from chassis ground on the second & third supplies as as the
>>>> article
>>>> says since they need to be floating (otherwise, the 5V from the first &
>>>> second supplies will be going straight to ground). If you didn't
>>>> isolate
>>>> them, you'll only see the 5V from the "third" supply...
>>>>
>>>> Joe, N3JI
>>>>
>>>> ----- Original Message ----
>>>> From: aborg <a_borg@yahoo.com>
>>>> To: Amps Amps <amps@contesting.com>
>>>> Sent: Thursday, June 1, 2006 9:09:38 AM
>>>> Subject: [Amps] Series PC Power Supplies
>>>>
>>>>
>>>> Hello Amp'ers,
>>>>
>>>> Quick technical question. I'm embarrassed that I
>>>> can't figure this out, but not quite a super tech yet.
>>>> Here it is. I am attempting to series 3 pc pwr
>>>> supplies. I can't seemed figure why I'm only seeing 5+
>>>> volts. The link to the article is below. Here is an
>>>> excerpt from the article. "Our second means of
>>>> utilizing this low cost power is to connect the +5 VDC
>>>> outputs of three separate supplies together in series.
>>>> This will provide you with +15 VDC at 25 amps on up to
>>>> the maximum rating of the supplies you have acquired."
>>>> Can someone be kind enough to relieve from my
>>>> embarassment ?
>>>>
>>>> Thanks
>>>>
>>>> http://www.antennex.com/preview/archive3/powers.htm
>>>>
>>>> Mike-KK4MS
>>>> a_borg@yahoo.com
>>>>
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