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  #11  
Old 11-28-2011, 11:03 PM
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HEATNBEAT HEATNBEAT is offline
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Quote:
Originally Posted by Marty Comstock View Post
I have heard of folk using them on Pullmax, but for what reason? other than the obvious, using it as a phase converter and what not, is it worth the expense if your pullmax is already running fine as it is?

I havent found the need to speed control my machine, I prefer it running at full speed. I think.

Marty
this is one reason
http://allmetalshaping.com/showthrea...hlight=pullmax
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  #12  
Old 11-29-2011, 09:54 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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Found some more information about converters and % of rated load on:

http://www.phaseconverterfaq.org/cap...converters.htm

Quote:
The loss of power or capacity when running a phase converter depends on what kind of phase converter you are using to run your equipment. With a rotary-phase converter, the answer is NO as long as the converter is large enough. A rotary-phase converter will develop the entire nameplate horsepower of the motor. The same does not happen with the static-phase converters.

Static-phase converters do not generally allow motors to develop full horsepower. Static phase-converters cannot balance a current into three different legs. When a static phase-converter starts the motor, it switches off the line, and the motor actually “single phases” one winding that carries most of the load. Once that winding reaches its full capacity, that’s all the load the motor can carry without tripping off or burning out. This usually occurs at between 60 to 80 per cent of the nameplate horsepower. This is the main reason static-phase converters are only recommended for small-horsepower or for single-motor applications.
This matches my experience although my experience is far from universal.
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  #13  
Old 11-29-2011, 11:17 PM
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My understand about VFD's is that if it is run from 3 phase supply it will run rate HP. I'm sure there will be some de-rating required as you get into huge HP. Its when it is run from single phase supply that the VFD has to be de-rated by about 1/3 or so. This is because of the loss of the 3rd leg of power. I'm no engineer but this is what I have been told. I currently run 3 VFD's. 1 on a 2HP Spinning Lathe (3HP VFD), 1 on a 5HP Press (7.5HP VFD) and 1 on a 10 HP Bradley Power Hammer (15HP VFD). Well, I don't run the Bradley yet but soon!

These de-ratings were the recommendation of the tech' at Factorymation.com The main requirement was Full Load Amps as the sizing factor.
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  #14  
Old 12-17-2011, 01:45 PM
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Default vfd motors

Are you running standard 3 phase motors?Any overheating problems at slow speeds?Or are you using vfd rated motors?Is your power supply single phase in to your vfd's.Thankyou ,tom
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Old 12-17-2011, 02:16 PM
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Quote:

Are you running standard 3 phase motors?Any overheating problems at slow speeds?Or are you using vfd rated motors?Is your power supply single phase in to your vfd's.Thankyou ,tom
Yes
It is recommended to use a fan if you run at slower speeds
yes, I run the recommended HP and have not had an issue
yes, I run single phase on my pullmax (2 hp)and my lathe(5hp)
I run 110 volt on my beadroller (1/4 hp)and my bammbamm(1hp)
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