i am looking for a way to make cheap and costeffective method for converting single phase electrical current into three phase, with or without capacitors, but not the rotary type, for running agricultural pumps, can anyone please help me, thanx regards

suryakant asopa

 

Sure, get an inexpensive VFD off e-bay. They make single phase input VFDs but you can use a three phase input unit fed by single phase if you derate the horsepower. They all have three phase output.

 

You would have better luck with alchemy. There is no cheap way to convert large amounts of single phase power to 3 phase. The most economical way is a rotary converter (motor gen set) but you stated you don't want a rotary converter.

Fred Townsend

 

These are probably not cheap options, but the ones that work well usually are not. For a comparison of different technologies, chech this site, there is a paper in the technical section that describes the different types, rotary, static, VFD and what they sell, a digital phase converter. http://www.phaseperfect.com/index.htm

You don't say what size motor you are wanting to run, but for smaller motors, my prefered method is a VFD. It gives you variable speed and most manufacturers make single phase models. The 3 phase models can be used on single phase too, just at a reduced capacity.

If you search on static phase converter, you will probably find some plans for building one somewhere, but I think you think about using better technology then that.

Mike

 

we have use a baldor vfd 230v 3 phase unit.
input 1 phase 230 and get 230v 3 output. this works up to 5 hp without derating of the drive.
hope this helps

 

Hello,
There a few AC Drives available that take 1 phase 200-240 Vac input and deliver 3 phase 200-240 Vo/p.
One example would be ABB's ACS140, (0.2 - 2.2kW). Check www.abb.com for more information.
regards/VGS

 

Depending on your horsepower look into single phase input ac drives. They are usually available in smaller sizes.

 

You need a start capacitor and a run capacitor ... size depends on the 3-phase motor you wish to run. You need a means of switching between the start and run cap ... a timer/relay adjustable 0-5 sec.

Any way you do this, the motor will only have about 1/2-2/3 of its rated horsepower.

Put the caps across two legs, put the volt input across the one of the first legs plus the remaining. Apply volts. Be prepared to shutdown quickly until you get the timer/relay to the right value. Don't apply load until the motor is running with no-load.

 

This link works for me on a 3 HP, 3600 RPM motor on a large radial arm saw.

http://home.att.net/~waterfront-woods/Articles/phaseconverter.htm

 

How cheap, In this part of the world, inverters are cheap, what size motor are you looking at?

 

hello, Mitsubishi makes a vfd that creates 3 phases from one. I use a FREQROL-U100 and it works well. Good luck.

Joe N

 

Hello Suryakant
You can run small 3 phase motors from a single phase supply using variable speed drives. The following manufacturers offer single phase supply VS drives for small 3 phase motors. Toshiba, ABB, Allen Bradley, Telemecanique, PDL.

Jamie Downs
New Zealand

 

Do you have a specification for (Voltage, Current, Power, Frequency)? How many pcs. per year do you need?

Kind regards

Maximilian Johannes Wurmitzer

 

The following is a page that will explain how to run a 3 phase motor on a 2 phase system. It will work . effeciency +- if it's a small 3 phase motor OK What will happen is that by feeding 2 phase to this system we can make a third ( ghost phase). IT IS NOT TRUE 3 PHASE,

http://www.team.net/www/shop-talk/hm3phase.html

 

Hi Joe ! Have you got a datasheet and/or application note for a FREQROL-U100 ? If yes, could you mail me a copy ? Thank you in advance.

Jesper Hansen ([email protected])