I also noticed that the Henry used a 10 ohm 50 watt resistor in the
primary of the filament transformer on the 3cx3000a7 tube amps. No
relays or anything else. This resistor was for a soft start and
voltage reducer and it remained inline at all times. It was as
simple as that. Guess it works pretty well cause I've pulled several
of those "old and very used" 3cx3000a7 tubes out of surplused Henry plasma
gens and ran them in my homebrewed 3cx3000a7 amp and they seemed to
operate at 100%.
Regards,
Larry N5BIP
-----Original Message-----
From: R. Measures [mailto:r@somis.org]
Sent: Friday, August 12, 2005 10:49 AM
To: Larry Carman
Subject: Re: [Amps] Sort Start
Good point, Larry. 0.5 seconds is enough -- of course with the
exception of heater-type tubes.
On Aug 12, 2005, at 7:27 AM, Larry Carman wrote:
> The Henry RF generator using a 4 KW power supply at 4000 VDC and a
> filter
> choke
> only use a .5 second soft start. The 1/2 second delay seems to be
> plenty
> even
> with 30 mf of caps and no filter choke. I've been running this
> arrangement
> or years. Too much soft start in certain instances will cause the
> bypass
> relays
> to energize too slow and cause relay clattering amongst other problems.
>
> Regards,
> Larry N5BIP
>
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com]On
> Behalf Of Will Matney
> Sent: Tuesday, August 09, 2005 11:30 AM
> To: amps@contesting.com
> Subject: Re: [Amps] Sort Start
>
>
> You can add a soft start, some do and some don't. A 10 second delay
> though
> is a little too long for the soft start on the HV transformer. You
> only need
> about 4 to 5 seconds as that's actually over the time it takes for the
> transformer to settle down. Some circuits are a little faster than
> that.
>
> Best,
>
> Will
>
> *********** REPLY SEPARATOR ***********
>
> On 8/9/05 at 11:15 AM Rich wrote:
>
>> Gentleman, I have started bread boarding my power supply. So far I
>> have
>> it set for the filament transformer and fan to come on first, run for
>> 3
>> ( adjustable ) min then kick in a relay for 0 to280v to the HV trans
>> , I
>> have a 50ohm 100 watt resistor in line for 10 sec then full voltage
>> (as
>> set by the autotransformer) to the HV transformer.
>> The caps bank will be 33uF at 6000vdc ( 3 caps 100mF 2000vdc each ),
>> transformer will be set 3000 to 40000vdc.
>> Before I bolt it all down and hard wire it do I need a soft start for
>> the filament?
>> The tube is a 4-1000a
>>
>> Rich , kd0zz
>>
>> _______________________________________________
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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
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>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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