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[Amps] V regulation on single phase big amps.

Subject: [Amps] V regulation on single phase big amps.
From: "jim.thom" <>
Date: Sun, 6 Aug 2023 08:23:45 -0700
List-post: <>
Here's the issue with the V regulation on the 10 kw 6m amp. Total length (1
way) from plate xfmr primary, to the new 50 kva pole pig xfmr across the
street is a whopping 267'. And of course, double that or 534' for the
complete loop. Then add in any non perfect splices or crimps. The power
company uses aluminum wire for the drop line into the home...and 1 gauge
smaller as well. If aluminum is used, it needs to be 2 x gauges bigger, not
1 x gauge smaller. Everything between poles is aluminum, and that also
includes the 14.4 kv line as well as the 240/120 stuff.

Scotts driveway is real long....and that part of his drop wire is all
underground, in conduit. It comes out, out of the grnd at the road, up a
20' pole, then across the an angle, and terminates on the 40'
pole with the pole pig xfmr.

Ideally, new cu wire, and bigger gauge needs to be pulled through the
existing conduit, replacing the old, undersized junk. If existing conduit
is too small, bigger diam conduit needs to be installed. Ideally, a new
pole needs to be installed on his side of the street, and the 14.4 kv line
wired across to his side of the street...with a 75 kva xfmr on the new pole.
Apparently, the preferred method of installing 400 amp service to the home
is to install a new 400 amp meter base. Then TWO, 200 amp cable assy's are
wired to the new 400 amp meter base. One pair of cables goes to the
existing 200 amp panel....and a 2nd pair of cables going off to a NEW 200
amp panel. Then the new install is easy peasy.

At that point, the V drops have been minimized. Only other option after
that is done, is to add more uf to the filter cap assy.
This is the problem when using high powered PA' residential area's.
The B+ supplies are typ just a FWB + a C filter. They are UN regulated to
begin with.

On a side note, PSUD-2 will factor in the DC resistance of that 534' total
loop length. That just gets ADDED to the plate xfmr's primary DC
resistance. DC resistance of the plate xfmr primary on the bigger xfmr's,
is typ just a fraction of 1 ohm.
You start increasing the resistance on the pri side, you can see the
effects asap in PSUD2 / spice / LT-spice. It screws everything up.
The peak current, every 8.3 msecs will make u gag. It's 60 amps every 8.3
msecs on an Ameritron AL-1200 amp, running at 1.5 kw cxr...on a 240 vac /
60 hz circuit. On a 10 kw out amp, it's typ 400++ amps every 8.3 msecs. Do
the maths. The peak V drop, every 8.3 msecs on that 534' long loop is just

And all that peak current also has to flow through any mains fuses,
breakers, relay contacts, contactors, fuse holders, etc. This is why all
that stuff has to be oversized.
Then when the HV filter uf is increased, peak currents also increase...or
try to. I have found that greater uf used in the HV filter is always a
benefit...and results in better dynamic regulation on ssb / am. And also
slightly better static regulation. It also results in less ripple, as
ripple is in inverse proportion to filter C. (double the uf, and 1/2 the
ripple etc).

Later Jim VE7RF
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