Re: {Collins} Oddball question for an ART-13/DY-17

The Collins Amateur Radio Club in Cedar tried to power an ART-13 demo in the
Main Plant parking lot a couple of years ago with a Collins 639G-1B power
supply.  That supply is a 175 pound linear unit that was the first design
project for a Collins engineer who went on to become an accomplished power
conversion expert.  It was spec'd at 75 amps at 28 VDC, but would maintain
regulation at double that.  However, the ART-13 would trip the supply
breaker on transmit, so we had to abandon the project.  

The 639G-1B supply was designed to power the 718U-2 vehicular 400 watt HF
SSB system.  The contract for those systems was relatively small, but the
supply became the "standard" 28 volt supply in the Collins factory for test
bay use.  I was fortunate enough to acquire a few of those supplies from the
old Collins surplus store and still have a couple for my 718U-2 and bench
supplies.  I donated one to the Fifi project a couple of years ago for
ground use.

I attempted to power a 1 KVA rotary inverter to supply 3 phase 400 Hz and
found that the starting current on those big brutes tripped the 639G
breakers, but I found that adding a pair of batteries in series across the
28VDC line worked nicely.  Only problem is that the whine from those
inverters can be heard for at least two blocks, so I have to limit my
618T/ARC-190 operating time to daylight hours.  

Those old dynamotors may be hard to find, but I think they should be used
whenever possible.  With a reasonable amount of TLC, they should be
operational for generations to come.  

Jim w0nkn

-----Original Message-----
From: Collins []
On Behalf Of Scott Johnson
Sent: Wednesday, June 18, 2014 9:06 AM
To: 'Max Cotton'; 'Reuben Popp'; collins@xxxxxxxxxxxxx
Subject: Re: {Collins} Oddball question for an ART-13/DY-17

This looks like a great deal, but I would bet that it doesn't have enough
stored energy to reliably start a DY-17, I think you will still need to
float a couple of batteries across it.  I have found, as a general rule that
a switching supply needs to be rated at near the surge current of the device
to properly power it.  If it is too small, it will usually current limit,
resulting in a slow start, or worse yet, locked rotor, which can overheat
the dynamotor windings and commutator, or else the supply will simply fault
and shut down.  I have used telecom switchers, and to start a big dynamotor,
it took three of them (100A ea.) in parallel to get it moving quickly.

-----Original Message-----
From: Collins []
On Behalf Of Max Cotton
Sent: Tuesday, June 17, 2014 11:29 PM
To: Reuben Popp; collins@xxxxxxxxxxxxx
Subject: Re: {Collins} Oddball question for an ART-13/DY-17

Reuben, I use one of these to power all my aircraft mil radios, 27V 100A
plenty of power, handbook is available online, ebay number is
320926294519 these are exteremely electrically quiet too.
just a happy customer. Oh by the way you have to connect one or two of the
pinouts together to make it work, email me and I'll let you know which ones
the are.
73 Max

----- Original Message -----
From: "Reuben Popp" <driador@xxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Wednesday, June 18, 2014 4:07 AM
Subject: {Collins} Oddball question for an ART-13/DY-17

> Hey all,
> This isn't necessarily a Collins-specific question, so my apologies in 
> advance if I'm asking this in the wrong place.
> I have an ART-13 here that (one day) I hope to revive and get it back 
> on the air.  It's in serviceable condition I think and appears complete.
> That
> being said, I also have a extremely well-kept DY-17A dynamotor that I 
> would love to use to power said transmitter as it was originally 
> intended.  Yes, it might be crazy as opposed to building my own solid 
> state supply, but it (the dynamotor) is doing nothing at this point 
> playing the part of a _very_ expensive paperweight.
> The ART-13 page over at Western Historic Radio Museum states that a
> PP-1104
> charger could power the dynamotor, but apparently those are far and 
> few between these days.  The guys over at Fair Radio said they haven't 
> seen any in about ten years.  I don't get out to the big fests and 
> can't get to Dayton, so I'm asking you all here.  Do you guys ever see 
> these out there still, or even better, if you were in my shoes, what 
> would you use to run the DY-17A?
> Thanks in advance
> Reuben

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