The critical features of that Airpax breaker are its current rating and
the fact it has no extra time delay. That its the fastest available.
Hence pure magnetic, no hydraulic or thermal time delay. Airfax makes or
made the same characteristics in several different packages. The most
inexpensive surplus sources of similar breakers were sold out in hours
of their mention on this forum.
Researching time delays is detail, I found the Buss MTC-16 standard fuse
is as fast as the Airpax breaker for carrying 20 amps. A fuse is always
rated to carry 125% indefinitely so it carries 20 amps, but trips faster
at an overload. I have run my Corsair II on my homebrew high efficiency
FET regulated 32 amp station supply for years, and I have blown a few
fuses while tuning with full power and a manual tuner.
The other thing you need with a big station supply is an external power
relay for the Tentec since its front panel switch can't carry the full
20 amp DC load. I used an automotive 30 amp cube relay, typically sold
for under $4 or 5 at auto stores, or under $3 from Mouser. I wired the
switch to the coil through a diode to act as a reversed polarity
protector also and doubled that with a back biased diode across the coil
which also significantly reduces inductive kick that could cause the
front panel switch contacts to arc on opening. When used with a tentec
supply and cable, the radio's front panel switch is on the line side
(120 volts AC) of the power supply.
73, Jerry, K0CQ
On 11/21/2010 8:39 AM, Roger Rippy wrote:
Just a quick followup to an email I sent earlier;
I searched some previous discussions on this
list dated March 2003 and 2006 and found the
answers to the Airpax and mechanical circuit
breaker question. I think that I can say that
I learned a good deal from these threads to
include a good small quantity source for the
Airpax T11-1-20.0A-01-10A-V breaker. I think
it would at some point be good to clear off
all the individual power supplies and go to
a central distribution point powered by a linear
supply. Oh well.....projects for later Rip W7RIP
Roger& Marie Rippy Bozeman, Montana
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