Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Other Topics => Topic started by: stingray_65 on March 22, 2015, 12:23:37 pm
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Hey guys,
Ive been away for a few weeks on another project, I've acquired a new to me CNC mill.
Problem is it has a 3 ph 5hp motor.
The servos and controls can all be run on single phase 220 vac easily.
VFD is not an option due to HP rating and the motor itself is not rated for inverter use.
Static converters are not an option due to losses. I might get 2 hp of performance.
SO that leaves rotary phase conversion as my last option.
Has any here ever used a rotary converter?
how reliable are they?
any help and opinions are appreciated.
Ray
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Hey guys,
Ive been away for a few weeks on another project, I've acquired a new to me CNC mill.
Problem is it has a 3 ph 5hp motor.
The servos and controls can all be run on single phase 220 vac easily.
VFD is not an option due to HP rating and the motor itself is not rated for inverter use.
Static converters are not an option due to losses. I might get 2 hp of performance.
SO that leaves rotary phase conversion as my last option.
Has any here ever used a rotary converter?
how reliable are they?
any help and opinions are appreciated.
Ray
one of the directors of the campus machine shop where i work uses one at home for a bridgeport mill. i'll ask him. IIRC when i chatted with him about it a couple of years ago, was that you need to down-rate the HP rating of the motor if you use the static type, as you have already stated, and why he moved to the rotary.
knowing just enough to be a danger to self, i'd probably pull the trigger on this one:
http://www.ebay.com/itm/UL-7-Pro-Line-7-5HP-UL-Listed-Rotary-Phase-Converter-NEW-Made-USA-/290902628206?pt=LH_DefaultDomain_0&hash=item43bb25d76e (http://www.ebay.com/itm/UL-7-Pro-Line-7-5HP-UL-Listed-Rotary-Phase-Converter-NEW-Made-USA-/290902628206?pt=LH_DefaultDomain_0&hash=item43bb25d76e)
--pete
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WOW
Never saw this brand when I did my search.
The 7.5 is a little out of my budget, but the 5 hp fits nice.
doesn't leave me much room to grow, but in a 12 x 10 shop i just dont have much room period.
Thanks for the lead Pete.
Ray
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Generally a rotary converter is as much machine as the motor it powers.
You have to ask if you can get a single-phase motor to replace the one you got. Might make more sense than a lump AND a lump.
5HP is a big load for a single-phase line, but "only" 20A-25A. I have a heater that big.
Single-phase forces a choice of hard-start (compressor) or easy-start (fan, saw) design.
WHAT are you hogging-out that you need all of 5HP?? The guy on the island lathe-turns 8"x60" *marble* columns on an old industrial metal-lathe which can't be 3HP.
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Farm Show came, and what is in it?
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My old Bridgeport is 240v single. However, I used a rotary phase converter on my wire EDM that I used to run in the basement. Lots of VERY sensitive electronics in that puppy. Never had a bit of problem and talking with the manufacturer of the EDM, they had no problem with it either - just make sure it is sized properly. Be careful of the listed "rating" on some of these good deals. I bought mine from Phase-A-Matic. They use Baldor motors (who are just down the road from me) so you know they are good. Here is their website and it has lots of good info to be aware of when you buy.
VFD's and static are a pretty dirty square wave which causes a lot of heat. If they use a leg for electronics, table feed motors, etc., you could have some problems
Jim
http://www.phase-a-matic.com/RotaryModels&Prices.htm (http://www.phase-a-matic.com/RotaryModels&Prices.htm)