[Milsurplus] Harris RF-110/112 combo: Single-phase possible?

[jwatkins]

Hi All,  

 

I would do a Google and (surprisingly) Ebay search on Rotary converters, it
seems that you can run a 3 or 5hp 3 phase motor using a smaller 1 phase
motor to get it rotating and then pull the third phase off of the 3 phase
motor.  I will see what I can find, but plans are on Google to build these,
and the 3 phase motors are on Ebay, and from what I can find available from
some Air Conditioner places  that have been pulled from scrap units.  3HP
would give you around 2000 watts of 3 phase at 721 Watts/HP.  This is
starting to get interesting.

 

Cheers,

 

John  WD5ENU/A45XV

 

From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of WA5CAB at cs.com
Sent: Saturday, May 12, 2007 8:37 PM
To: kyrrin at bluefeathertech.com; milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Harris RF-110/112 combo: Single-phase possible?

 

Bruce,

I have no familiarity with the RF-112A, but the short answer, if it has a
3-phase transformer (and not three single-phase transformers) is no.  You
can't run it off of single phase.  The Lambda unit as I currently understand
it, turned out to be a transformerless supply, using the pole pig as its
input transformer.  Thus it was three single phase supplies whose DC output
was summed.  Operating it from single phase amounted to operating two of the
three supplies, taking a 33% power hit, and having 120 Hz instead of 180 Hz
ripple on the output.  And letting the third supply sit dormant (built in
spare as it were).  

The long answer is that you might talk to somone who sells phase converters
for operating 3-phase motors off of single phase lines.  I've never talked
to anyone who has used one to run a 3-phase power supply.  I suspect that it
might have a better chance of working if the Harris were only run AM or FSK
but it would be worth looking into.

And if you get an honest answer, please post it back here, as I've been
thinking of trying to acquire an AN/URT-23 and the 3-phase supplies seem to
be more plentiful than the single phase ones.

In a message dated 5/12/2007 9:02:21 PM Central Standard Time,
kyrrin at bluefeathertech.com writes: 



Fellow techies,

    The recent thread about the three-phase high-current switching supply,
and some tricks to use it on single-phase, got me thinking about a Harris
RF-110A kilowatt linear amp I have, along with its RF-112A three-phase power
supply.

    Specifically (and I'm going to probably need someone who knows this
hardware to answer this): Is there any way at all I could run the RF-112A
off of 220V single-phase (well, two-phase if you want to get technical about
it -- two hots plus a neutral)? I've looked at the schematic for the 112,
and found that the main power transformer primaries are a bit of a
complexity nightmare. I'm not well-versed enough in polyphase circuits to
recognize more than some of it.

    Failing any sort of tweaks or mods to the 112, I would have to find an
RF-124 power supply, which was designed to run the amp off single-phase to
begin with. More specifically, I'd have to find it within local-pickup
distance (west coast from WA State to the Bay Area), considering that
there's no way I could handle shipping on something that heavy.

    So: Any mods? Or does someone have an RF-124 power supply they don't
need, and that's within striking distance for me?

    Thanks much.



Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at houston.rr.com> (Backup email)


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