I forgot about Hsu being overseas. He would have a 50 Hz transformer
and the formula I showed was for 60 Hz at 12 kilogauss. The one for
50 Hz is;
TPV = 5.82 / a
a = 0.206 x sq rt of P
P = ( a / 0.206 )^2
a = Core area in square inches
TPV = Turns per volt
P = Power in Volt Amperes or Watts if load is resistive.
Sorry about that. I use 60 Hz so much I forget talking about 50 Hz
all together.
Best,
Will
--- In ham_amplifiers@..., "craxd" <craxd1@...> wrote:
Actually everything goes up by a factor of 1.2. Not only does the
core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down. Whoever
designed the transformer should know this I would think, and
account
for it so as to acchieve the same power output.
Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has to
be done anyhow to hold the extra wire over the higher turns so it
has
to be stepped up even larger to increase the wire diameter. If the
turns are dropped to just accept the larger wire, the flux density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux density,
but the cost will go up. Another alternative would be add more iron
which would lower the flux density, but again, cost goes up.
If one was in production, it would be best just about it to use a
50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
users as it would run cooler with a lower flux density. This would
make a one size fits all transformer so the chassis wouldn't have
to
be modified between the two.
Best,
Will
--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:
Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to turns
ratio change, gfz
pentalab <jim.thomson@> wrote: --- In
ham_amplifiers@..., "Hsu" <Jbenson@> wrote:
Thanks,Will
Could tell me the power rating of TL922 HV transformer?
Thanks again!
73! Hsu
----- Original Message -----
#### HSU.... as far as I know.... from memeory... the plate
xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
CCS.
#### In the case of the RL drake xfmr.... that rating is for 60
hz only..... and like Will sez.... it MUST be de-rated for 50
hz. Several VK/ZL's I have spoken too over the years have
complained of over heating the RL drake xfmr, when run on 50 hz.
### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
[1977] , it had primary taps for 100/120 200/240.... in Japan
they use 100/200 V and 50 hz. So In that case, I'd assume
the yaesu plate xfmr would run on 50 hz.
### IF the TL-922 xfmr has pri taps for 100/200v.... you can
asume it will run ok on 50 hz. IF it only has taps for
120/240... then asume it's 60 hz only. It seems to me that
the TL-922 is popular in the UK... and I believe they use 220 v
50
hz.
### In normal operation... the TL-922 xfmr would be good for
600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb.... and
maybe a little less on CW.
### I agree with Will. You can't go by weight alone. Case in
point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
[36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
used in a C input filter.... and when running 1900w PEP output
from the linear.
### In the case of the Hammond, it was a high reactance type,
with a center tap, designed for tube rectifier's... and had a
high
68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
ohm DC sec... is made for a C input filter.. and is of the LOW
reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
resistance secondaries.
### These Peter Dahl hypersil C core plate xfmr's flat out won't
blow up, or overheat, doesn't matter what you do to em. They are
either the most underated things, or the greatest things since
sliced bread... take ur pick.
Later... Jim VE7RF
