[Amps] HF2500 Power Supply Caps

[Carl]

----- Original Message ----- 
From: "Steve" <g8gsq72 at gmail.com>
To: <amps at contesting.com>
Sent: Tuesday, April 08, 2014 9:40 AM
Subject: Re: [Amps] HF2500 Power Supply Caps


>> Make sure your transformer is up to it - big caps can mean higher peak
>> currents and more I^2xR in the windings.
>>
>> Steve
>>
>> ## I thought the same thing.  I used PSUD to see the results  with 
>> various
>> values used.
>> In actual usage, there is no issue.....provided the xfmr is the low Z 
>> type,
>> which most are.   The ones that heat up a bit are always the high Z
>> types..... made for choke input supplies.
>
> Yes, for any decent transformer it's not normally a problem - my comment 
> was meant as a caution against taking it for granted. I've seen it where a 
> transformer (not a choke input type) was marginal for the load so voltage 
> was sagging and someone thought they would add lots more C to try and prop 
> it up.
>
> As you say, PSUD is your friend.
>
> Steve


Not all transformers designed for SS and capacitor input are low resistance. 
Ive come across several 1-4 kVA units designed for FWB that have 2-4 times 
the winding resistance that many seem to take for granted as being fine for 
all sorts of wild amounts of C.

Carl
KM1H