KPA500 fans

If the fans are running on the capacitor charge when the amp is turned off,
wouldn't they still run if you pulled the plug?

John KK9A



Don Wilhelm wrote:

John,

Because after power off, the fans are powered by the charge in the
KPA500 capacitors discharging, I do not think that is a requirement -
but not a bad idea in any case.

73,
Don W3FPR

On 2/1/2017 7:53 PM, John Marvin wrote:
> I know this thread is supposed to be closed now, and hopefully this
> would be obvious, but you should also wait for the fans to stop before
> "pulling the plug". You should always turn the KPA500 off with the
> switch (or the KPA utility) first, wait for the fans to stop, then you
> can use the back switch or a power cord switch.

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[Don Wilhelm]

John,

The answer is YES, but with any device using any kind of processor, it
is always better to use the power-off sequence before "pulling the
plug".  I don't know if this applies directly to the KPA500, but it
certainly does for the K3(s) and P3 as well as the KX3 and the KX-line.

In other words, to be safe, shut it down before turning off the mains power.

73,
Don W3FPR

On 2/1/2017 8:55 PM, [hidden email] wrote:
> If the fans are running on the capacitor charge when the amp is turned off,
> wouldn't they still run if you pulled the plug?
>
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[k6mrmagnet]

Nope. Just tried it (I had to know).



The fan is controlled by the uC via a BJT and voltage regulator controlled by FETs. Without standby power everything turns off.



Ken K6MR



From: [hidden email]<mailto:[hidden email]>
Sent: Wednesday, February 1, 2017 5:56 PM
To: [hidden email]<mailto:[hidden email]>
Subject: [Elecraft] KPA500 fans



If the fans are running on the capacitor charge when the amp is turned off,
wouldn't they still run if you pulled the plug?

John KK9A



Don Wilhelm wrote:

John,

Because after power off, the fans are powered by the charge in the
KPA500 capacitors discharging, I do not think that is a requirement -
but not a bad idea in any case.

73,
Don W3FPR

On 2/1/2017 7:53 PM, John Marvin wrote:
> I know this thread is supposed to be closed now, and hopefully this
> would be obvious, but you should also wait for the fans to stop before
> "pulling the plug". You should always turn the KPA500 off with the
> switch (or the KPA utility) first, wait for the fans to stop, then you
> can use the back switch or a power cord switch.

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[Nr4c]

I suspect they need to be switched into the circuit, done with the logic when the amp is turned Off.

Sent from my iPhone
...nr4c. bill

> On Feb 1, 2017, at 8:55 PM, <[hidden email]> <[hidden email]> wrote:
>
> If the fans are running on the capacitor charge when the amp is turned off,
> wouldn't they still run if you pulled the plug?
>
> John KK9A
>
>
>
> Don Wilhelm wrote:
>
> John,
>
> Because after power off, the fans are powered by the charge in the
> KPA500 capacitors discharging, I do not think that is a requirement -
> but not a bad idea in any case.
>
> 73,
> Don W3FPR
>
>> On 2/1/2017 7:53 PM, John Marvin wrote:
>> I know this thread is supposed to be closed now, and hopefully this
>> would be obvious, but you should also wait for the fans to stop before
>> "pulling the plug". You should always turn the KPA500 off with the
>> switch (or the KPA utility) first, wait for the fans to stop, then you
>> can use the back switch or a power cord switch.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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