I used on-rush current limiting series resistors on the 240vac input
to my 4200 volt transformer and one on the 5v filament of my 8877
amplifier. The filament drew normal 11A, so on-rush was
huge. Simple resistor-capacitor time constant timer controlled relay
to short out large 50w and 100w
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"With switching mode powersupplies (as in the KPA500 and 1500 and most of the
solid state amplifiers with ps included) usually no further measures are
necessary or would help in that respect as most SMPS have soft start circuits
included."
KPA500 nominal 60 V PSU is not a switching mode supply.
nthal
Sent: Sunday, January 19, 2020 1:11 PM
To: David Wilcox
Cc: Elecraft@mailman.qth.net
Subject: Re: [Elecraft] Ameritron 240V inrush limiter: any benefit on a
KPA500?
The simplest circuit, which I added to my TL922, is a relay operated from a
DC supply with a capacitor across the coil. The ci
The simplest circuit, which I added to my TL922, is a relay operated
from a DC supply with a capacitor across the coil. The circuit can be
set up to provide from a fraction of a second to a much longer delay.
When the relay is de-energized, a small resistance is inserted in series
with the line
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Guys,
This is very interesting. Is there a Wiki site where all your explanations are
collected together. I am Interested in the magnetization of the iron in the
transformers and the effect of the turn on current phase causing an over
magnetization of the iron core and drawing too much current
Just like the 1930s vintage Western Electric at WKOP when I worked there in the
early 60s. When you turned it on, it went click-click-click-click BLANG.
Two tubes, 12 kV on the plates, about 1 amp plate current for 5 kW output.
Victor 4X6GP
> On 19 Jan 2020, at 1:45, Fred Jensen wrote:
>
> 1
10 KW homebrew FM broadcast TX [not kidding -- KPFK 90.7 Los Angeles in
the late 50's, 4 4-1000A's* in parallel driven by a 1 KW stage] had a
step-start using mechanical time-delay relays.** It limited the inrush
current to the filter capacitors of the 5.5 KV plate power supply. It
was part o
On 1/18/2020 12:14 PM, Victor Rosenthal wrote:
The power switch in some of those amps like the SB220 or TL922 is
highly stressed. T
Another cause of high input current is transformer saturation. If the
core happened to be fully magnetized in one direction when last turned
off, and the AC h
On 1/18/2020 12:14 PM, Victor Rosenthal wrote:
The power switch in some of those amps like the SB220 or TL922 is highly
stressed. T
My late '70s vintage Ten Tec Titan amps include circuity to minimize the
turn-on transient, at least some of which is due to charging of the
capacitors in the LV
Well, I don't totally agree. The power switch in some of those amps like
the SB220 or TL922 is highly stressed. There is a big "thump" sometimes
when they are turned on at the right point in the cycle. I also believe
that slower application of filament voltage to a 3-500z or similar
lengthens t
..@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Macy monkeys
Sent: Saturday, January 18, 2020 7:42 PM
To: Ron Durie
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Ameritron 240V inrush limiter: any benefit on a
KPA500?
Thanks, Ron! I understand NO, hi!
John K7FD
On Jan
.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Macy monkeys
Sent: Saturday, January 18, 2020 7:42 PM
To: Ron Durie
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Ameritron 240V inrush limiter: any benefit on a
KPA500?
Thanks, Ron! I understand NO, hi!
John K7FD
> On Jan 18, 20
Thanks, Ron! I understand NO, hi!
John K7FD
> On Jan 18, 2020, at 10:06 AM, Ron Durie wrote:
>
> NO. Solid state amps do not need inrush protection. 73's
>
> Ron WB4OOA
> Elecraft K-Line
>
>
>
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> Ho
Solid state amps do not require added inrush protection.
And most correctly designed tube amps do not need inrush protection.
In cases where the design, usually HB ones, have excessive current
capacity in the heater or filament transformer, or in cases where HV
transformers have insufficient
NO. Solid state amps do not need inrush protection. 73's
Ron WB4OOA
Elecraft K-Line
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Does an inrush limiter like the Ameritron ICP-240 offer any benefit to the
KPA500?
Thanks, John K7FD
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