Greg, The Phase-Perfect Digital Power Converter does look great (better than the static or rotary). They claim 97% efficiency. I'd love to have great efficiency, and not have to even consider heat management. I can do an awful lot with the medium-weight power tools I have, but I'm tired of having to coddle my machinery at all, thus the desire for bigger, heavier stuff. However, a 10 hp digital converter is close to $3,000, which would gobble up one of the $reasons for using 3-phase equipment. Your solution might be the best for a small shop. According to what I read (by no means claiming to be an expert here), the static converters start a 3-phase motor by applying 240v power to two of the three legs, plus power from a capacitor to the third leg; then run it on two legs, thus the loss. How are you figuring the loss in your system? Bob In a message dated 4/12/2009 12:55:07 P.M. Pacific Daylight Time, gnewell at ameritech.net writes: Bob, I run them all off of a single 30 amp circuit which, of course, means that I have to unplug and plug in when I want to change machines. I can tell you that the power reduction is nowhere near 1/3. I had heard when I bought the converter that the power reduction could be as much as 10% for which I said “big deal”. It’s harder on the life of the motor too since it builds up heat faster. I don’t consider this a problem either since I’m not using them for extended periods of time therefore the heat buildup is less. I paid about $200 for the converter if memory serves (which, increasingly, it does not). I’ll have to read your article here when I get the chance. Greg Newell Greg's Piano Forté www.gregspianoforte.com 216-226-3791 (office) 216-470-8634 (mobile) P.S. if you really want to do it well try looking at the phase perfect website. At one time they declared no reduction whatsoever. Lot’s of money required for perfection it seems. http://www.phaseperfect.com/ From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of BobDavis88 at aol.com Sent: Sunday, April 12, 2009 3:32 PM To: pianotech at ptg.org Subject: Re: [pianotech] newman planer, powermatic bandsaw Greg, Thanks for your note. I'm hoping to add some heavier machinery some day, and this looks like it's worth some further examination. I did a little digging, and a static converter seems to reduce the rated horsepower by 1/3, which might or might not matter, depending on what you're starting with. This site seemed to have some good reading: _http://www.phase-a-matic.com/StaticApplicationNotes.htm_ (http://www.phase-a-matic.com/StaticApplicationNotes.htm) It looks like you might expect to pay maybe $300 for an 8-12 horse-worthy static converter to run motors of 7 or 8 hp. The site lists some applications the static converters might not be appropriate for. A rotary converter looks more like $1,500 - $2,000. How much was yours? Do you run all these off a single 30 amp 220 circuit? 50 amp? Multiple circuits? Thanks, Bob Davis **************Feeling the pinch at the grocery store? Make dinner for $10 or less. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000001) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090412/47bedcc5/attachment.html>
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