I'm looking to upgrade some of my shop equipment, and I'm tired of the
lousy quality control and metal casting coming out of Chaiwan. I'd
love to buy American/Canadian, but the remaining manufacturers are
priced so high they're out of my ball park.
In looking at much of the used Oliver/Northfield/Yates equipment for
sale out there used, the vast majority seem to be three-phase motors.
Working out of my home, that would mean either replacing the motors or
getting a phase converter. I could get into a static converter for
about $200 - $250, but then I'm looking at 70% max power.
I'd prefer to go the rotary route, but of course, then I'm looking at
$600 - $700 for even a small unit.
Can anyone tell me about their experience with such a beast? I know
the "quality" of the power coming out of a rotary is still not as good
as true three phase, but does this cause any damage to the motors over
the long haul? Are there any other headaches they present?
Thanks in advance.
Good advice...I just took it. Googled the group first, but most of the
info on it went so far over my non-electrical head I could have used my
spinning head as a rotary converter!
So I posted the question with a caveat that, I'm electrically ignorant,
please be kind.
BTW, one of the reasons I'm starting to look down this path is your
recent auction post. I would give my ( __ ) to have that 36"
Northfield, but I've got nowhere to put a nine-foot-tall, 2700 lb. band
saw other than my backyard! (And even it might collapse under the
weight!) Now, if you were selling a 20" Northfield, I'd be all over it
like skank on a Britney Spears!
Good luck on selling your babies. And here's to them going to a good
One other thing...I noticed someone asked you what the resaw capacity
was, and you replied that you didn't know. Certainly a fair question,
but by looking at the picture, I think you could just have safely
answered something like "Honda Civic."
Rotary phase converters are the way to go if you will have more than one 3
phase tool. You will only need one converter big enough to run your largest
machine if you will only be running one machine at a time. The output isn't
really 3 phase, but it's close enough that the motors don't care. I have
several print shop customers that have been running their presses on rotary
phase converters for years without having any more motor problems than
customers who have real 3 phase. Keep in mind that they take more (about
140%) single phase current input than the 3 phase output current, so you
will need to budget your power for it. A transformer will draw almost no
power when no load is connected and rotary phase converters are similar, so
it is common to turn them on at the beginning of the day and off at the end
of the day. The 3 phase tools are then always ready for use. If there are
any control circuits in the tools that run on single phase (2 of the 3
phases) be sure to hook them across the 2 non created phases of the
E-mail me direct for more info.
<wood firstname.lastname@example.org> wrote in message
You can also use a rotary converter to buffer power surges, so that
the average input power is less than the peak output power, due to the
energy stored in the flywheel. Look here for a biggie:
Motor - generator sets and rotary phase converters ARE NOT THE SAME. While
it is indeed true that the flywheel of a motor - generator set will buffer
power surges and sags, a rotary phase converter will not. Rotary phase
converters don't have a flywheel and they don't have any generating
capability. They are nothing more than a rotating transformer and most don't
even have an output shaft.
I built a rotary phase converter out of a large 3 phase motor for a home
shop. It has been running for over 35 years, providing 3 phase power to a
Bridgeport milling machine, a Cincinnati lathe, and a horizontal mill. It's
large enough to allow any two of these to run at the same time.
"Juergen Hannappel" < email@example.com> wrote in message
At what point does dedicated three-phase service become cost effective?
Transformers are pretty pricey for the initial install I've heard. A
site for 3-phase like Bill Pentz did for dust collection would be
excellent. Any takers?
One thing to remember.. Three phase is almost "never"
available in residential areas. It is also fairly
rare in "light" industrial. It just depends on your
area and your power company.
Three phase typically uses a "demand meter" and that
can be right pricey.
That's the reason phase converters are fairly popular.
Jay Pique wrote:
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