[TenTec] Airpax

[Mike Bryce]

Bob and the group,

most likely for reverse polarity protection.

I designed a circuit and have a small pcb that has all the protection needed for any radio including over current. Haven’t done much with the project, but for those that are interested drop me an email.

The over current protection is faster than a fuse, and it’s adjustable 


Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
http://www.theheathkitshop.com/
J e e p
o|||||||o 

A man with one clock knows what time it is. A man with two clocks is never sure.

> On Jul 23, 2018, at 5:11 PM, Bob McGraw K4TAX <rmcgraw at blomand.net> wrote:
> 
> I agree on fuses, but one must use the correct fuse not only in amperage rating but also in thermal delay characteristic.   Not referring to Slow Blow fuses.
> 
> But I then do question "why is it the design of the Paragon, Paragon II, Omni V, Omni VI+, Omni VII, Eagle, Argonaut VI along with other radios using the same PA circuit include fuses on the back of the radio?"    These radios can be powered from supplies of much greater amperage capacity than required, and often are supplied from such.  Thus with a 50A supply the likelihood of excessive current exists up to the point where the fuse provides protection.   I don't recall reading in any of the manuals where additional current limit devices should be utilized.    Agreed that AIRPAX breakers are magnet breakers and are fast acting as well as the over current circuits in many power supplies.
> 
> Many radio manufactures have gone to blade type fuses typically found in automotive circuits.  There is a vast range of amperage ratings as well as thermal delay times.  Some of the fuses act as quickly as 20 ms while others have a much longer response time. They are not all created equal.  Selection of the correct fuse is critically important for proper circuit protection.   Just any old fuse won't do!
> 
> http://www.littelfuse.com/~/media/automotive/datasheets/fuses/passenger-car-and-commercial-vehicle/blade-fuses/littelfuse_atof_datasheet.pdf <http://www.littelfuse.com/%7E/media/automotive/datasheets/fuses/passenger-car-and-commercial-vehicle/blade-fuses/littelfuse_atof_datasheet.pdf>
> 
> 73
> 
> Bob, K4TAX
> 
> 
> 
> On 7/23/2018 3:14 PM, Greg S via TenTec wrote:
>> Fuses are cheap. I run my Omni VI Plus at about 70 Watts output, and use a 10 Ampere fuse. Occasionally it pops, butI have a good supply of replacements. Cheaper than any power supply, or breaker. Problem with fuses is the thermal delay action. One probably couldn’t run any of the 100% duty cycle modes this way, but I never do.
>> Just another experience/suggestion.
>> Greg, KC8HXO
>> 
>> 
>> Sent from my Linux device
>> 
>>> On Jul 23, 2018, at 13:02, Bob McGraw K4TAX <rmcgraw at blomand.net> wrote:
>>> 
>>> While I don't have the 18A airpax breaker, I can suggest one use an automotive 18A blade type fuse installed in the + line.   Provides equal protection but not quite the convenience of using it to turn the radio on and off.
>>> 
>>> Bob, K4TAX
>>> 
>>> 
>>> Sent from my iPhone
>>> 
>>>> On Jul 23, 2018, at 11:47 AM, Paul K. <hglent at frii.com> wrote:
>>>> 
>>>> I just picked up a Corsair II.  Wow!  It is a really FB rig, but I need a 18 Amp, Airrpax breaker for it. Do any of you fine folks happen to have one you could part with?  Or, what is the part number and source to buy on the market?  I've tried several suppliers, and found a 20 Amp, but no 18 Amp.  I tried to search the groups files, but just haven't figured out the search method.
>>>> 
>>>> If you can help, please email me off list.   WA0BAG at ARRL.NET
>>>> 
>>>> TNX   es   73 de   WA0BAG   ..
>>>> 
>>>> Paul K.
>>>> 
>>>> -- 
>>>> Paul K. WA0BAG
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