[TheForge] three phase converters, etc.

[Howell Steve]

Interesting, Ralph.
I thought most motor driven Nazels ran at 1100 RPM up to the 4 or 5B. It's
one of the ways they were able to get more torque out of less HP
What size is your pinion/drive gear? :  How many teeth and diameter of gear?
(I ask since I have characterized several 3B's this way and have a simple
formula to calculate the relationship to RPM).
I have a 1100 RPM 10HP on mine rigged for 230V and of course, saw one on
ebay months ago for 130 dollars left unsold. "would I ever need another?
Nah..."   

Might a motor switch be an easier option than trying to customize voltages,
etc? 

Steve

>>>>>>>>>

        Well, Maybe I ought to fess up as to what I'm really thinking!

        The Nazel 3B I'm rebuilding has a 575 volt, 3 phase motor that runs
at 875 RPM.  So, I was thinking of making a 10 Hp phase converter that would
make 240 - then going with transformers to boost the voltage to the motors
correct plate requirements.  I have a 10 Hp idler motor available to me, and
the transformers off a really large industrial control panel with high
voltage ratings.........so I was wondering if that might be an option as
compared to taking a tractor PTO to run the pinion gear to the hammer, or if
it came right down to it......... maybe a chevy Cavelier front wheel drive
friction unit developed a few miles north of here.        (Oh, Hi Mike)
:-)

Ralph

        PS, 3 phase is not an option - the nearest line is miles from here.


----- Original Message -----
From: <xlch58@swbell.net>
To: <theforge@mailman.qth.net>
Sent: Monday, January 19, 2004 10:47 AM
Subject: Re: [TheForge] Fwd: Shop tools & layount (3-phase converter)


> Yes, to get optimum performance you should add run capacitors,
> especially if you are only running a single motor off of the
> converter.   I expect that your unit has both run and start.    The run
> capacitors are there to balance the current, rather than voltage.
> For the average  home shop where you just want to be able to run that
> single bargain industrial machine I would just wire up a second motor of
> same or larger size as a rotary converter, use a rope to start  it.   If
> your machine motor gets hot with your usage, then I would go to the
> trouble of balancing the current with capacitors, otherwise just keep it
> simple and be happy.    The power company doesn't measure power factor
> for residentials.    For your situation Ralph,  it would be worth
> monitoring the current with an amp meter and adding capacitors as needed.
>
> Charles
>
>
> Ralph Sproul wrote:
>
> >Charles,  Thanks for writing this reply to the converter topic.
> >
> >I have one question.  On the Static converters your mentioning the size
of
> >the capacitors for starting and running loads.  Does one have to "tune"
the
> >third leg of a rotary phase converter with capacitors?
> >
> >I'm asking as the store bought 7 1/2 HP  rotary phase converter that was
> >included in my Iron worker package deal has a bank of capacitors in
> >it.........is this just for starting? or is this to bring the
manufactured
> >leg up to acceptable voltages?.......or both?
> >
> >
> >
> 


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