[Elecraft] K3 on supply with amp = NO - WAS "Juice" your K3?

[Jim Miller KG0KP]

Those are my thoughts also.  Follows is my way of isolating the "shock" of 
an 80 amp audio modulated load from my K3 input power supply.

I do run my radio bench with a 70 amp linear Astron supply BUT I have a 
seperate Power supply buss(pair) and a battery buss(pair)(plus a seperate 
ground buss bar).  The two busses are connected to each other by a knife 
style disconnect from an air-conditioner cutoff (new and removed from box 
and mounted under bench) BUT there is 25 feet or wire involved and the spare 
wire (about 20 of the 25 feet) is coiled up as a sort of (wimpy) inductor. 
BTW, the 4 buss bars (2 bar pairs) are 1/4 by 1 inch aluminum and the ground 
buss is 1/4 by 1 inch copper mounted on the upper back of my bench.  The 
wire is long and is 14 ga on purpose to add resistance to partially isolate 
the "shock" of the 80 amp requirement (during audio peaks) of the ALS500 
solid state amplifier.  The amp is wired to the battery buss with 3 pairs of 
12 ga wires (14 inches) and the battery buss is wired to the battery also 
with 3 pairs of 12 ga wires (12 inches).  The battery is two LARGE 
automotive batteries (one stolen for my truck recently not yet replaced). 
(Flame on about gasses if you wish, I'm not listening)  I don't want that 
shock on the power supply AND I don't want my K3 to have to try to operate 
properly on that kind of voltage that must be very noisy (and it matters not 
if the power goes out, I keep on operating).

The battery buss (and batteries) is held up in non-use times by a battery 
maintenance charger (of no use during operation).  Not one of the $7 ones 
that are useless on this size battery (if any), these are about $30 and are 
larger and "intelligent" and monitor and only add charge as needed.

73, de Jim KG0KP

----- Original Message ----- 
From: "Dave Hachadorian" <K6LL at ARRL.net>
To: "Elecraft reflector" <elecraft at mailman.qth.net>
Sent: Wednesday, March 11, 2009 11:53 PM
Subject: Re: [Elecraft] K3: Do you "Juice" your K3?


> Earlier today, I remarked that one of my K3's was running
> warm in the NAQP RTTY after an extended number of RTTY CQ's.
> Tonight I did a little experiment - key down at 100 watts
> for four minutes while noting PA Temp and fan speed. It
> turns out that there really is no problem. Both K3's behaved
> identically and both leveled off at PA Temp = 64C after
> about 3 minutes. For the record, here are the results (best
> viewed with Courier font):
>
> Time   Temp  Fan
> 0:00    26C   0
> 0:26    37    1
> 0:44    41    2
> 1:19    50    3
> 1:45    55    4
> 2:40    60    4
> 2:50    62    4
> 3:15    64    4
> 4:00    64    4
>
> Room temp was 77F.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
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