Power Supply Question

[John]

Hello Bruce. I am not sure why the message I sent was blank but I will try
again. I am not sure why power supplies are rated in different ways. I think
it has to do with marketing. I cannot say for sure but I think the 15 Amp DC
Output rating is probably a peak surge rating which means it can take 15
amps surge for just a moment at a time in cases like you might run into with
SSB operation for instance. If you had a transmitter that says it needs 5
AMPS then it still might need a surge of 15 Amp peak. There are several ways
to rate a power supply and many could answer the question more scientific
than I can. There is RMS CCS ICS just to name a few of the ways power supply
current is rated. The short answer is it depends on the way you will use the
supply. If you try to use the supply in an application that says it needs 15
amps then this supply is likely to soon fail. On the other hand if you are
using it in SSB operation and it only draws 15 on the peaks then maybe this
supply will suit your needs. If the operation will require a carrier and
draws more than 5 AMPS continuous then the supply will fail. Hope the answer
was not more confusing than the question..

73 de KE5NZY

-----Original Message-----
From: BSugarberg [mailto:bsugarberg at core.com] 
Sent: Tuesday, November 20, 2007 11:15 PM
To: john at hughes.net
Subject: Re: Power Supply Question


Hello John,

So why does it say "DC Output: 15 Amp" on the front panel?

73, Bruce WA8TNC
================
John wrote:
> This is the info I have found on this unit..
> 
> Heathkit PS-1175 AC Power Supply
> Operating voltage: 12 to 14.5 volts DC adjustable
> Output current: 10a intermittent (10 minutes max)
> 		 5a continuous
> 
> 	So Bruce, it is a 5 amp power supply with 10 amp surge. For instance
> 5 amps at continuous use, and 10 amps for key downs less than 10 
> minutes long are fine. 15 amp draw is never ok with this supply. Hope 
> this helps. 73 de KE5NZY John Godfrey

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