Date: Sat, 2 Feb 2013 19:49:31 -0500
From: "Col. Paul E. Cater" <paulecater@gmail.com>
To: Amps reflector <amps@contesting.com>
Subject: [Amps] Power Supply for Solid State
Good day all,
I am looking for ideas on transformers to use in the power supply of a
solid state VHF amp. I'll require 50VDC at 33 amps. Golf cart
transformers have become expensive. Any ideas on the cheapest way out?
Regards,
Paul
WD8OSU
## don’t even go that route. 50 vdc switching type supplies are a dime a
dozen these days.
The telco’s are all using switchers in recent years. Typ they are aprx 6-7
ich tall, x 4” wide
x 14” deep. Each rated for 3.3 kw CCS. 50 vdc @ 66A CCS..without breaking
a sweat,
and barely warm. We would typ use 6 of em in a 25” wide rack for 20 kw.
Then start stacking
them one shelf above the next etc..in a 7’ tall rack x 25” wide.
## $475.00 each. They typ run on 208 vac 60 hz single phase....and will
operate on any voltage from
165 vac up to 315 vac. They will also run on any line freq from 40-70 hz.
The beauty is the power factor (PF)
is unity at all phase angles. The harmonics have also been eliminated on the
240 vac input side too.
## The output voltage can typ be adjusted from 46-60 vdc. You can also wire
em for neg grnd, pos grnd,
or float the output. They weigh very little too, just a few lbs. We
installed thousands of these things 4 years ago,
and they are on 24-7-365. Zero maintenance, and never had to replace one yet.
## do it the conventional way with pass transistors, xfmr, etc, and you end
up with a heavy behemoth...complete
with lousy PF. Ferro resonant xfmrs was popular too, with it’s 3rd winding.
Sorta like a sola constant V xfmr But
they are big and heavy. The ferro resonant typ 50 vdc supplies used by telco’s
for the last 50 years are now availab;e surplus.
They can’t give em away. The smaller 25 and 50 A CCS types can be had with
240 vac 60 hz single phase inputs.
The bigger 100-200-400-800 A types are all 3 phase 208 vac types.
Later.... Jim VE7RF
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