[TenTec] TenTec Digest, Vol 37, Issue 73

[Douglas]

>Date: Fri, 20 Jan 2006 23:42:20 EST
>From: OTAKEBI at aol.com
>Subject: Re: [TenTec] Paragon Problem - Solved
>To: tentec at contesting.com
>Message-ID: <2b2.337a314.310315ac at aol.com>
>Content-Type: text/plain; charset="US-ASCII"

>I've never used a home-brew supply but I have run an
Astron RS->35M with a Corsair II and an OMNI V using
an Airpax 18 amp >instant on the Corsair II and an
Airpax 20 amp fast break on >the OMNI V. I have had
the same supply for 15 years never a >problem.
>Before I went Ten Tec I used the same supply with
Kenwoods.
>The Ten Tecs have been happy for about 8 years on the
Astron.
>The Ten Tecs have original finals and drivers.
>I have never had to go into them with my irons to
repair a PA  >problem.
>I think that the Ten Tec supplies are great that is
why I told >the other fellow to get one and if he
can't to junk the supply >he has and get an Astron
with the breakers.
>If you were to call TT and speak to Scott you will
find that >the TT supplies use the same type of
breakers as the Airpax.
>In fact the #1140 Circuit Breaker that TT says to use
in their >manuals is the on off switch in the power
supplies they sell.
>Ten Tec no longer have the 1140 breakers so they say
to use the >Airpax if you go mobile or use another
supply other than TT.
>No breaker will protect 100% if the supply goes south
or is out >of regulation.

>My car seatbelts are not guaranteed not to
malfunction but  I >would not drive without them
especially if I built the car.
>Dan/N4VET

Dan,
I don't know where you got your info about Ten-Tec
supplies using an Airpax breaker but it just isn't so.
This has been covered before in prior postings.

All the Ten-Tec power supplies that I've seen, and I
currently own 5 different models, use an electronic
current shutdown system.

There is an internal current shunt in the supplies. If
there is excessive current, a voltage is developed
great enough to trip a SCR shutdown circuit. This
circuit ELECTRONICALLY trips out the voltage
regulator, removing the supply's output voltage.

There are two similar circuits in the supply. One is
for over current and the other is for over voltage
protection. Both shutdown points are adjustable. The
over voltage circuit's SCR dead shorts the output in
the event of pass transistor failure, thus tripping
the over current circuit. A careful study of the
supply's schematic will point out the above.

The on/off switch on Ten-Tec supplies is a simple
switch - not an Airpax breaker. An Airpax breaker is
like most breakers in that it's electro-mechanical in
operation. The Ten-Tec over current shutdown is purely
electronic in operation, making it extremely fast.

If I remember correctly, even the external model 1140
breaker that Ten-Tec used to sell was NOT an AIRPAX
braker. It was a small box containing a similar
electronic, SCR triggered shutdown circuit. I still
have one that I use on one of the older single pass
transistor output supplies.
73,

Doug/WA1TUT