[time-nuts] 4 KV Power Supply Recommendations

[J. Forster]

I completely agree, and said so at the outset.

Best,

-John
===============


> As I said its slowly seems to be pumping down.
> Let it go for 2 weeks.
> I have had to do that with travelling wave tubes...
> Cost $2 for electricity.
> If that doesn't work go for the big guns.
>
>
> On Sun, Jan 17, 2010 at 5:03 PM, J. Forster <jfor at quik.com> wrote:
>
>> I just looked at eBay and most everything suitable is well over $200.
>>
>> -John
>>
>> ============
>>
>>
>> > The small Bertan modules in particular are extremely stable and
>> > well-behaved.  You get exactly the voltage that you program, accurate
>> to
>> > within about a tenth of a percent.  No spikes, no drift, and no
>> obnoxious
>> > AF
>> > whine like you get from the HP modules.
>> >
>> > The smaller ones are good for 500 uA, and the larger modules are good
>> for
>> > 2-5 mA depending on model.
>> >
>> > -- john, KE5FX
>> >
>> >> -----Original Message-----
>> >> From: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com]On
>> >> Behalf Of J. Forster
>> >> Sent: Sunday, January 17, 2010 8:00 AM
>> >> To: Discussion of precise time and frequency measurement
>> >> Subject: Re: [time-nuts] 4 KV Power Supply Recommendations
>> >>
>> >>
>> >> The small modules are nice, but many PMT supplies do not go to 5 mA.
>> 5
>> >> mA
>> >> @ 4 KV is 20 Watts output, more at the input. That's a lot for a PMT
>> >> supply.
>> >>
>> >> Also, remember that some supplies designed for gas lasers have a HV
>> >> "kick"
>> >> at startup that may go to 20-30 KV.
>> >>
>> >> -John
>> >>
>> >> ==============
>> >>
>> >>
>> >> >
>> >> >> Since it appears to be making some progress, I'd be tempted to
>> just
>> >> >> continue. The pump rate of an ion pump varies with the current, so
>> it
>> >> >> seems you are pumping, just somewhat more slowly than w/ the
>> external
>> >> >> supply, as long as you are not overloading the internal supply.
>> >> >>
>> >> >> If you don't have a lab supply, get an old transformer from some
>> >> vaccum
>> >> >> tube gear and use the HV secondary to drive a Cockroft-Walton
>> >> multiplier
>> >> >> to get to what you want. Pretty trivial to build these days. Put
>> the
>> >> >> primary on a Variac to adjust the voltage.
>> >> >>
>> >> >> BTW, a commercial supply at that voltage and current is going to
>> cost
>> >> >> several hundred dollars.
>> >> >
>> >> > The nicer Glassman rack-mounted supplies are spendy, but smaller HV
>> >> > modules
>> >> > for PMT and laser work are common and inexpensive.  Go to eBay
>> >> and search
>> >> > for "<manufacturer> supply", where common manufacturers include
>> Emco,
>> >> > Bertan, Spellman, Fluke, and Glassman.  E.g. item 220539685243 .
>> >> These
>> >> > smaller modules tend to sell for well under $100, and are handy to
>> >> have
>> >> > around.
>> >> >
>> >> > -- john, KE5FX
>> >>
>> >>
>> >>
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>>
>>
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>