[Amps] AL-1500 pi network capabilities

[Will Matney]

Rob,
It's hard to tell the exact rating of the transformer. He gives a weight 
of 32 pounds, but that's total weight including the coil. I just figured 
a core for an op the other day to fit an Alpha 76 he was overhauling. 
The core weight came to 24 pounds for a rating of 2400 Vdc under load at 
800 milliamperes. The total weight would have been more than this. This 
would have had about a 2800 Vdc OCV value. This was to run a pair of 
3CPX800A7's.

In order to determine what they done, I would need to know the physical 
core size so I could figure the area of the central core itself. In this 
design, it is known as a "shell core" using two C-cores to make it up. 
This is the preferred way to emulate an EI core. Now it said it would 
produce 3200 Vdc which would probably sag to about 2800 Vdc under load. 
On 10 meters, it look like it was running 800 milliamperes of plate 
current. 800 mA would require a wire size of 22 gauge wire in the HV 
secondary and about 12 gauge wire in the 240 Vac primary. The problem 
is, even though the core could be sized right, or even over-sized, they 
could have skimped on the wire size. In amateur service, running ICAS, I 
recommend running the wire size at 750 circular mils per amp. However, I 
have seen some running it from 300 to 500.

If I had a transformer to autopsy, and find out all these details, I 
could tell how many watts it was good for. Or, if somebody could take 
these measurements, it can be reverse engineered easily. Weight can tell 
you something, but not everything.

The tank capacitors has to be rated by their air gap. I can't see any 
part numbers to convert into a size. The capacitors usually have their 
air gap in the part number someway. These capacitors look like Oren 
Elliot M-73 capacitors. The part number would be stamped on the back end 
bell of the cap itself. The 10 meter tank coil looks like it's made with 
either 3/16" or 1/4" plated copper tubing. The lower freq. coil looks to 
be either 12-14 gauge plated wire. It also looked like it had been hot 
in one of the pictures up torward the top of the coil.;

http://www.hamradiomarket.com/Articles/Ten%20Tec%20Centurion%20Images/422010.jpg

If I had the air gap on those caps, I could tell you in about 5 seconds 
what their rating was.

Will Matney


Not to digress (too much), but the comments on the SB220 tank and power handling and the AL-1500 tank being similar but for over 2 kw caused be to go back and take a look at some on-line photos of the Centurion innards:

http://www.hamradiomarket.com/Articles/Ten%20Tec%20Centurion%20Images/422010.jpg

here's one that gives some scale:

http://www.hamradiomarket.com/Articles/Ten%20Tec%20Centurion%20Images/422020.jpg

Any comments as to their power handling capability?


also,
stock fan arrangement:
http://www.hamradiomarket.com/Articles/Ten%20Tec%20Centurion%20Images/42207.jpg

stock h.v. xformer:
http://www.hamradiomarket.com/Articles/Ten%20Tec%20Centurion%20Images/42209.jpg


tnx
rob/k5uj