--- In ham_amplifiers@..., R L Measures <r@...> wrote:
On Sep 26, 2006, at 5:02 PM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...>
wrote:
RICH SEZ.. SSB has a duty cycle of less than 20%, so it's quite
different than RTTY.
### Dream On.... unless you chopped all the audio off below
350 hz..... or the plate current meter ballistics are out to
lunch.
During an ahhhhhhhh, I see about 1/3 of A0 anode current. If one
transmits half the time, that's a duty-cycle of 1/6.
#### I'd call that 1/3.... NOT 1/6th. What if I give a 5 min
disertation? or some contester calss 'cq' for 3 mins
straight?
### The big kicker is gonna be CW. Dashes are gonna be at
least 3 x as long as dots. I set my dashes so they are 3.6
x longer than dots.... send cw at 10-16 wpm.... and u are in
for a big surprise....... duty cycle is WAY UP.
RICH SEZ Resin potting helps dissipate heat from deep in the core.
### agreed.
RICH SEZ ....That would work. With a C-filter, for every ampere
indicated, expect 10 amperes peak.
### SAY WHAT ?? I used Duncan's pwr supply modeller.... and
even though the dc resistance of the primary is only .08 ohm.....
Z on primary... using their software is more like 68-70 ohms....
and peak current on the 240 v side is aprx 3.75 X steady
state readings.
### ANYTHING between 3-10 X just means EVERYTHING from
contactor's to wire, buss bar, breakers, etc... between main
200 A panel.... and up to and including the connections to the
Dahl plate xfmr primary has to be way over sized.... to
minimize V drops !!
### We took those surplus 135 A rated 3 x pole contactor's..
and simply paralled em with 1" x1" aluminum angle stock....
to make em into one big 400 A SPST-DM contactor assy. Then
stick one such assy in each leg of the 240 line..... and the 3rd
one does the step start. ....works good too. So does
slopping on 'cool amp' silver plating compound on tall the
contacts... dc resistance drops to zero every time.
### A fwb gives better reg than a doubler... for the same size
caps.
Sure, but with the required size caps for a FWD, the % regulation
is pretty much the same.
### You would have to at least double the size of the caps in a
doubler. A doubler's caps only gets charged 60 x per
second....... a FWB's caps get charged 120 x per second.
That 50 ohm glitch R we have in the B+ doesn't help
matter's any.... I lose 150 vdc right there.
... which is not noticeable at the Rx end. Originally, the
Plywood Box amplifier stupidly had a 25w glitch resistor -- most
definitely a blunderous mistake.
### agreed... BUT 150 v is a 150v... which sucks. You don't
want any less than 50 ohms either........ but any more than 50
ohms means more v drop... and more heat.
### We used 2 x paralled 100 ohm-225 watt wire wounds in the
latest project...... works good. Even with some initial HV
faults during testing [which took out one or both BUSS 3 A
sandfilled HV fuses]... the resistors didn't flinch. I was
expecting the huge instantaneous magnetic field from the
resulting 160 A to be strong enough.. to destroy em.
### 4 x 200 ohm 275 watt globars in parallel [older 60's CX
type] also work superb in glitch service.
Later.........Jim VE7RF
