[Boatanchors] Homebrew Power Supply

Tue Apr 9 18:18:20 EDT 2013

Did you folks not read that the Elmac supply 
uses CHOKE INPUT filtering?

AND, that the power supply delivers 475 VDC 
under load?

* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk at hotmail.com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
* * * * * * * * * * * 

> CC: k2gkk at hotmail.com; w7qho at aol.com; drewrailleur807 at yahoo.com; w5jdy at cox.net; boatanchors at mailman.qth.net
> From: Chnord at comcast.Net
> Subject: Re: [Boatanchors] Homebrew Power Supply
> Date: Tue, 9 Apr 2013 18:12:06 -0400
> To: bcarling at cfl.rr.com
> 
> That 6146 must be screaming in pain :)
> 
> Carl Nord
> Sent from my IBM 360
> 
> 
> 
> On Apr 9, 2013, at 6:06 PM, "bcarling at cfl.rr.com" <bcarling at cfl.rr.com> wrote:
> 
> > If it needs 1400v CT then those 350-0-350v and especially 350-0-350v transformers will not cut the B Plus mustard.
> > 
> > Bry Carling
> > http://www.af4k.com
> > http://alltheaboveband.com
> > 
> > 
> > ----- Reply message -----
> > From: "D C _Mac_ Macdonald" <k2gkk at hotmail.com>
> > To: "mac" <w7qho at aol.com>, <drewrailleur807 at yahoo.com>, "- Cox" <w5jdy at cox.net>
> > Cc: "boatanchors at mailman.qth.net" <boatanchors at mailman.qth.net>
> > Subject: [Boatanchors] Homebrew Power Supply
> > Date: Tue, Apr 9, 2013 5:59 pm
> > 
> > 
> > The "factory" supply for the AF-67 is the PS-2V. 
> > 
> > It is rated to deliver nominal 6 VAC @ 6A, or 12 VAC 
> > @ 3A for filaments, 230 VDC @ 80 mA and 475 VDC
> > @ 170 mA. Separate plate and filament transformers 
> > are provided. 
> > 
> > There is a 24 VAC tap on the filament transformer to 
> > be used for control or a bias supply. 
> > 
> > Outputs of the plate transformer T2 are 1400 V C.T. 
> > and 800 V C.T.
> > 
> > Output of the filament transformer T1 are 6VAC @ 1A 
> > for a 6X5GT rectifier, 5 VAC @ 3 A for a 5U4G rectifier, 
> > plus 6 VAC @ 6A or 12 VAC @ 3A for transmitter filaments
> > and 24 VAC @ .1A for control/bias.
> > 
> > Both high voltage circuits are full-wave using choke input
> > filtering. 
> > 
> > If you'd like to borrow my power supply manual to copy, Joe, 
> > let me know.
> > 
> > 
> > * * * * * * * * * * * 
> > * 73 - Mac, K2GKK/5 * 
> > * (Since 30 Nov 53) * 
> > * k2gkk at hotmail.com * 
> > * Oklahoma City, OK * 
> > * USAF & FAA (Ret.) * 
> > * * * * * * * * * * * 
> > 
> > 
> > 
> > 
> > 
> > 
> >> From: w7qho at aol.com
> >> To: drewrailleur807 at yahoo.com
> >> Date: Tue, 9 Apr 2013 14:26:06 -0700
> >> CC: boatanchors at mailman.qth.net
> >> Subject: Re: [Boatanchors] Homebrew Power Supply
> >> 
> >> Let's see, this arrangement would require a transformer with a 
> >> 185-0-185 vac secondary good for at least 350ma. No idea where to 
> >> come up with such a unit.....
> >> On Apr 8, 2013, at 7:26 PM, Drew P. wrote:
> >> 
> >>> Joe Walden wrote:
> >>> 
> >>> "Hello,from Joe w5jdy in Okla... I am in the process of building a 
> >>> power
> >>> supply for a Multi Elmac Transmitter model AF-67 and the Receiver 
> >>> PRM-7....
> >>> The particular specs I need is the power transformer secondary voltage
> >>> ?ac-0-?ac.... This voltage is rectified with a solid state bridge 
> >>> and has a 16 mfd input filter capacitor....... I need the output 
> >>> voltage to be 500
> >>> vdc at 250 ma..."
> >>> 
> >>> I assume that the full wave bridge would be connected to the outside 
> >>> of the transformer's HV secondary winding, and that the bridge's 
> >>> negative end would be connected to common.
> >>> 
> >>> With this arrangement and typical losses, 370 VAC to the full wave 
> >>> bridge would give you about 500 VDC with a capacitor input filter 
> >>> connected to the bridge's positive terminal. With the center tap 
> >>> connected to another capacitor input filter, that other filter will 
> >>> show about 250 VDC.
> >>> 
> >>> Drew
> > 
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