[GreenKeys] Loop Supply

[Doug Hensley]

I've refreshed maybe a dozen Model 28 factory loop supplies and without exception,
they all used 220 uF capacitors between 250VDC and 450VDC.  And FWIW, I never saw
more than3 components: one cap and two rectifiers composing a half-wave rectifier.

Here's a typical unit.  These are used in both ASR & KSR:

[cid:1eb9d189-9dd9-4c44-b5bd-9d59785c03ee]

Doug W5JV




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________________________________
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> on behalf of Lester Veenstra <m0ycm at veenstras.com>
Sent: Friday, December 14, 2018 3:13 PM
To: 'John, W9DDD'; greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Loop Supply


Actually ordered 220 MFd / 250 vdc caps for the project



Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y

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From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of John, W9DDD
Sent: Friday, December 14, 2018 3:34 PM
To: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Loop Supply



I'm foggy about the specifics of the 15 (about 57 years of cobwebs), but you show in your drawing what appears to be magnets wired in series instead of parallel, which would be normal for 60ma.  You can go 30ma with parallel connection, normal was 20.

John, W9DDD

On 12/14/2018 2:18 PM, Xavier Andrieu via GreenKeys wrote:

The capacitance of the output cap is 100 microfarad and there is a bridge rectifier.



Xavier



De : greenkeys-bounces at mailman.qth.net<mailto:greenkeys-bounces at mailman.qth.net> [mailto:greenkeys-bounces at mailman.qth.net] De la part de JC White
Envoyé : vendredi 14 décembre 2018 21:07
À : GreenKeys at mailman.qth.net<mailto:GreenKeys at mailman.qth.net>
Objet : Re: [GreenKeys] Loop Supply



Just a quick question and suggestion:  What is the capacitance of the output electrolytic cap in you 120 volt supply?  Since adding a cap gives you greater range I would guess you are not getting the current and voltage you think at the selector mags... obviously additional capacitance provides a bit more oomph (very technical engineering term)...  your schematic shows no details of how the 120 vdc is derived so ???



John

WB6BLV



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