I have seen breakers let go for no apparent reason. It seemed like it was a mechanical failure in the breaker.

Dick, n0ce


On 5/16/2016 5:27 PM, Rick Bates (WA6NHC) wrote:
Is it possible that it 'belched' and the power reset is what really fixed it?

73,
Rick WA6NHC

Tiny iPhone keypad, spell check happens

On May 16, 2016, at 1:40 PM, Todd Ruby <[email protected]> wrote:

Well Ron, I guess there's a first time for everything. Although the radio was 
deaf and dumb, I had display function and it looked as it normally does after 
turning on the power. There was just no receive nor output power.

I turned it off, pressed the 20 amp circuit breaker on the rear panel and sigs 
were coming through the headphones and I had full power.

Today it's also operating perfectly.

73

Todd

On May 16, 2016, at 3:30 PM, Ron D'Eau Claire <[email protected]> wrote:

Todd responded to me off the reflector that he lost all power to the K3 so it 
wasn’t the 20A breaker. That only controls power to the KPA3. The front panel 
is still powered and the receiver continues to work.

I suggested it might be the self-resetting breaker inside the K3. That will 
turn it off completely. Actually power will still be on the KPA3 module and 
anything plugged into the 12V external power connector on the K3 rear panel, 
but the K3 itself will look dead with no front panel lights, receive or other 
functions until it cools and resets itself.

I’ve never had an issue with either breaker opening unexpectedly.

73, Ron AC7AC

From: [email protected] [mailto:[email protected]]
Sent: Monday, May 16, 2016 12:18 PM
To: Ron D'Eau Claire; 'todd ruby'; 'Elecraft Reflector Reflector'
Subject: Re: [Elecraft] circuit breaker

I believe Todd is referring to the breaker on the K3, not his house panel 
circuit?
Ron has some good advice, but I wonder how common this circuit breaker operates?

I looked thru my manual for more info on it.  The block diagram shows it as a 
25A fuse,
text and device indicate 20A circuit breaker, but NO  info on the type 
operating curve, or current vs. time for minimum trip?

I have a 10A circuit breaker on my 40Ahr battery supply and it has never 
tripped.  It is a thermal time delay like most house breakers.

Anyone out there have any clue?   Wayne?

Mike  AC5P



On Monday, May 16, 2016 12:28 PM, Ron D'Eau Claire <[email protected]> wrote:


The normal underlying cause for the breaker to open is over-current. That's
a 20A breaker that protects only the KPA3 100 watt amplifier module. The
first thing I'd do is check the current drain from your power supply on the
band where you experienced the problem. First set the power to 10 watts so
the KPA3 is bypassed and note the total current drain key down. Now crank up
the power and see if the part used by the KPA3 is pushing 20A. For example,
if your total current at 10 W was 3A, does the total at 100 watts approach
23A? IF so, the breaker was simply doing its job. Note that circuit breakers
are not precision devices so it may trip a couple of amperes one way or the
other from 20A.

A primary reason for excessive KPA3 current is a high SWR on your antenna
system. The higher the SWR, the less efficient the KPA3 becomes and the more
current it has to draw to produce the power.

A defective breaker can also start tripping at lower currents.

73, Ron AC7AC

-----Original Message-----
From: Elecraft [mailto:[email protected]] On Behalf Of todd
ruby
Sent: Monday, May 16, 2016 9:08 AM
To: Elecraft Reflector Reflector
Subject: [Elecraft] circuit breaker

Would anyone venture to guess what would cause the circuit breaker to trip
on a K3? Mine did all of a sudden yesterday. Fortunately, my friend
suggested the reset and voila, I am back on the air. But if there is an
underlying cause, I think it would be wise to be aware of it so as to
preclude this episode from repeating. Any thoughts are welcome.

73

todd

WB2ZAB

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