[ARC5] Wow...

Sun Aug 1 19:26:01 EDT 2021

Scott you are quite WRONG.  The CUCV series of vehicles uses a pair of 27Si GM alternators that are rather special, in that the alternators are not grounded internally.  One alternator “floats” above vehicle ground to charge/maintain one of the two 12V batteries in the vehicle. The other alternator is grounded via its ground terminal to charge the other 12V battery that is connected with the Negative “grounded”/connected to vehicle frame, and from that 12V battery, the normal vehicle electrics are powered.  The two batteries in series provide for starting and power to Radios and/or other equipment that requires 24 V.  I have owned and worked on too many CUCV, and actually understand the electric system, which is a tribute to the GM engineers that designed it.

Have you considered the load on a 12V system for a unit that provides 28V at 50A, and the size wire required?  A very inefficient and questionable  solution.

R

From: scottjohnson1 at cox.net <scottjohnson1 at cox.net> 
Sent: Sunday, August 1, 2021 6:48 PM
To: 'Robert P. Meadows' <rpmeadow at bellsouth.net>; 'Tim' <timsamm at gmail.com>; 'MARK DORNEY' <mkdorney at aol.com>
Cc: 'ARC-5 List' <arc5 at mailman.qth.net>
Subject: RE: [ARC5] Wow...

Most of the converters were switch mode that made a roughly 1500 Hz squarewave, stepped it up , and rectified it.

Later ones were more refined, using PWM techniques for load following,  earlier ones used a vibrator.  There were also 12/24ZV dynamotors.

I have several varieties around here, including some NOS high tech ones that out put 50A at 28V for a 12 V input. 

There are also dual voltage alternators, and the CUCV used two alternators, 14V for the truck, and 28V for the radio equipment.

When I re-engined my M-715 with a GM 6L LS powerplant, I installed a second DR44G alternator that I modified with an isolated ground, it is stacked on top of the 14V electrical system, along with a second battery in series.  This gives me independent charging of the two batteries and is very reliable.  Plus, I have 145A at 28V available just off idle (minus the engine load).

Scott

From: arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net>  <arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net> > On Behalf Of Robert P. Meadows
Sent: Sunday, August 1, 2021 3:20 PM
To: 'Tim' <timsamm at gmail.com <mailto:timsamm at gmail.com> >; 'MARK DORNEY' <mkdorney at aol.com <mailto:mkdorney at aol.com> >
Cc: 'ARC-5 List' <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net> >
Subject: Re: [ARC5] Wow...

Now, that is a stretch, The CUCV is a 12/24 volt electrical system, specifically to run radios and to provide 24 volts for starting other vehicles.  The radio installation on the M1009 (Blazer) provided 24V (27.5v) power to a substantial terminal strip installed behind the passenger seat about 12 inches from the door post for power to the installed radio set that utilized a mount that attached at essentially the same location.  There were no 12/24 volt converters,

And further would someone tell me how you convert voltage?  

My point of reference is that I owned for several years a M1009, and at present have a M1008 and M1028, with all the manuals, references, etc.

R 

From: arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net>  <arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net> > On Behalf Of Tim
Sent: Sunday, August 1, 2021 5:30 PM
To: MARK DORNEY <mkdorney at aol.com <mailto:mkdorney at aol.com> >
Cc: ARC-5 List <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net> >
Subject: Re: [ARC5] Wow...

Scott is right.  There was a milspec 12 to 28 volt converter available for CUCV vehicles.  My Reserve unit had them in our Chevy Blazer CUCV's to power the VRC-46 (RT-524) sets.  1980's thru 1990's, did the job in Saudi Arabia and elsewhere...  I forget the nomenclature but I think it was an EMU-???  Transistorized of course, about 8x5x4 inches thereabouts...  I'd like to find one if anyone has a spare kicking around!

Tim

N6CC

On Sun, Aug 1, 2021 at 2:12 PM MARK DORNEY via ARC5 <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net> > wrote:

Just because Fair radio had a converter of some sort doesn’t mean it was available to the US military during WW2, or at any time, for that matter. 

Mark D. 
WW2RDO

“In matters of style, float with the current. In matters of Principle, stand like a rock. “.   -   Thomas Jefferson 

Sent from my iPhone

> On Aug 1, 2021, at 3:42 PM, scottjohnson1 at cox.net <mailto:scottjohnson1 at cox.net>  wrote:
> 
> There were many of those converters made for the military, mostly to allow
> 28V radios to be used in commercial vehicles (flightline pickups and vans,
> etc.)  Magnavox even made a little box that would accommodate a UHF or VHF
> radios such as the ARC-164 or ARC-186.  It accepted 12/24 VDC, or 115/230V
> AC, and had a built-in amplified speaker and mic jacks.  It even had a plate
> to mount an AT-256 antenna on top for portable use.  I have three of them,
> one with an ARC-164, one with an ARC-186, and one with an ARC-210.  We
> carried around a Wilcox 807 in the flight line van with an inverter, an
> upgraded to the little Magnavox box when they became available (the SOF
> truck had both VHF and UHF if memory serves).  I think I can remember line
> vans with ARC-27s in them, with an auxiliary alternator and 24V battery just
> for the radio.  Most vans just had UHF, but a few also had ARC-73s or
> ARC-49s for VHF.
> 
> Scott 
> 
> -----Original Message-----
> From: arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net>  <arc5-bounces at mailman.qth.net <mailto:arc5-bounces at mailman.qth.net> > On Behalf
> Of Hubert Miller
> Sent: Sunday, August 1, 2021 12:24 PM
> To: MICHAEL ST ANGELO <mstangelo at comcast.net <mailto:mstangelo at comcast.net> >; Ken
> <kgordon2006 at frontier.com <mailto:kgordon2006 at frontier.com> >; MARK DORNEY <mkdorney at aol.com <mailto:mkdorney at aol.com> >; kk5f at arrl.net <mailto:kk5f at arrl.net> ;
> ARC-5 List <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net> >
> Subject: Re: [ARC5] Wow...
> 
> Fair Radio for some years sold a cubical box with something like 8 inches on
> a side, that converted 12 DC to 24 DC. What was that thing for?
> -Hue Miller
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