Yes indeed Peter, 3-phase HV power supplies are very nice from several
points of view.
However, the discussion here started out in the context of a traditional
single-phase scenario with a simple reservoir capacitor on the output of the
full-wave rectifier. No filter chokes; just a solitary filter capacitor /
series cap bank.
I.e. what's found in the majority of commercial and homebrew ham radio
linear amplifiers. Reducing the filter capacitance to a minuscule 2 uF may
not cut the mustard in many amplifiers.
Leigh
VK5KLT
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Peter Voelpel
Sent: Friday, 11 May 2012 7:46 AM
To: amps@contesting.com
Subject: Re: [Amps] The power of an oversized electrolytic capacitor /
howmuch PS filter C is enough?
Here we can use the three phases for any purpose we intend to.
Maximum power is 55KVA with my installation.
In my HV power supply the 2µF capacitor is plenty, without it ripple voltage
is 4%.
73
Peter, DJ7WW
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Dr. David Kirkby
Sent: Donnerstag, 10. Mai 2012 23:20
To: amps@contesting.com
Subject: Re: [Amps] The power of an oversized electrolytic capacitor / how
much PS filter C is enough?
On 05/10/12 12:19 PM, Leigh Turner wrote:
> We can note the amplifier in question here uses a 4-1000 tetrode, and that
> such tubes exhibit a plate current virtually independent of plate voltage,
> i.e. tetrodes are a constant current device. Such a characteristic would
> make it more immune to ripple and noise on the B+ plate supply.
>
> Leigh
> VK5KLT
More immune than what?
Whilst the input current will be fairly independent of voltage, the input
power, and hence output power will change if the HT supply varies. That
leads to a loss of linearity.
If you have the ability, then using a 3 phase transformer could be
considered. Even without capacitors, the ripple is quite small, since unlike
a single phase supply, the input voltage is never zero.
I do have a 3 phase supply to my house, but it's not tempting to build an
amp with it, as it restricts severely where you can use it.
Dave
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