# FREQ DRIVES/MOTORS



## John J (Dec 29, 2007)

I found a great source for Frequescy drives. Single Phase. Can they be used on any motor? Or is there something special about the motor?


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## Greg Elmassian (Jan 3, 2008)

how about a link to what you are talking about so we are sure we are on the same subject? 

Greg


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## Michael Glavin (Jan 2, 2009)

JJ, 

I work with VFD’s (variable frequency drives) all the time, replacements, upgrades and more. Yes for the most part any three phase motor will work and some single phase motors are viable with VFD's. There are enhancements or spec built motors that tend to work better in some applications, but your standard AC induction motors are more common. Long gone are the days of multi-speed motors and their associated control circuits and components. Do you recall the term PWM or pulse-width-modulation; constant voltage and current models are typical. Infinite control from 1 RPM on up with many user adjustable parameters, such as torque boost, FWD-REV functions, ramped acceleration and braking and lots more…. 

Michael


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## John J (Dec 29, 2007)

Thanks Michael. That is was I was talking aboutl. We use them on the big Printing presses I work on. I wanted something for around the house that is single phase. One think I want to slow my Band Saw down so I can put a metal cutting blade in it. 

http://dealerselectric.com/mfg-subcat-item.asp?cID=28&scID=164&mID=-1 

The prices seem reasonable. 

JJ


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## cjsrch (May 29, 2010)

should work with any AC motor. they just use varrying voltage and pulses to simulate a sine wave of greater and lesser duration. 
build one once with a PIC micro controller as the core to power a fish tank pump and simulate random water current speeds


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## Totalwrecker (Feb 26, 2009)

JJ, 
On my bandsaw the speed is controlled by stepped pulleys and the V-belt location, motor speed is always the same. 

Will controlling motor speed affect the torque? At slower speed will the blade slow when the cutting gets harder? 

Seems to me with the motor getting less juice it will be affected by resistence.... 

John


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## Torby (Jan 2, 2008)

I think I'd ask them.


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## John J (Dec 29, 2007)

I thought with Freque Drives the Torque was somewhat constant.


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## Totalwrecker (Feb 26, 2009)

My limited knowledge comes from applying electric motors to various tools. Most reach their rated horsepower at 1350 rpm (I hope that's the correct #, I'm 15 years removed from that chore). To change the speed we changed the pulley sizes, leaving the motor to run at it's rated speed. 

John


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