Phase Converter

The VFD is necessary to convert the single phase supply you have to three phase which the motor needs. You cannot directly run a three phase motor off single phase.

Your options are - put in a VFD, switch to a single phase submersible pump, or run a three phase supply to the three phase motor.

Other than VFD, phase converter (as the subject indicated) is the only way that I know. There are two types of phase converter - Static and Rotary. For detail, see http://en.wikipedia.org/wiki/Phase_converter

- MS

I have been building converter boxes for many years that do what you need. I figured I would share the basic design concept and working system knowledge with everyone a while back so posted it on this website.

http://www.electro-tech-online.com/re-projects/100563-3-phase-converter-schematic-miller-system.html

Have you ever disigned a static phase converter ?

Do you know where I can get an squematic ?

Thanks very much tcmtech

I have lost track of how many I have built and sold now. I have personal use versions from .5 to 15 Hp that I use nearly every day that have been in use for many years so they are quite reliable if built properly. The design I put on that link is well tested and highly adaptable for use in a number of applications.

That link has both versions of the independent rotary type system and the on motor static type as well plus the base calculations for sizing and tips for tuning it to the exact motor and application. Plus it also includes the formulas for different power source frequencies and voltages too!

The design gives balanced phasing plus full starting and running torque as well which works well if a three phase source is needed to run a welder or other device that needs a stable three phase power source.

Not sure where you are located, but I purchased a 1.5HP 240V 1 phase to 3 phase VFD off of ebay for ~$40 (+$10 shipping). Like new and it works perfectly. If you can get tcmtech's converter parts cheaper than that, try his version first. The capacitor/relay version would have only cost me about $30, not including search and assembly time. However, I prefer having the full control of a VFD when the cost is reasonable. Good luck!

Well, another option is to put in a rotary converter. A single phase motor connected to the supply drives a 3-phase generator, which then connects to the 3-phase motor for the submersible pump. It's a bit silly, though, as it would be easier, cheaper and far more efficient to change-out the 3-phase motor listed for a single phase submersible pump.

You can have a try if you have option to take risk. Connect only two phases to motor terminal. Initially remove the capaitor connection. You may opt it.

On the 3 phase equipment I have in my welding shop I use 7.5 hp rotary phase converter I built myself from a kit I got off e-bay for 80 bucks, an old 7.5 3 phase motor, a used electrical enclosure box and some steel and time to build a stand and wire it up. I had a total 4-5 man-hours and around 120 bucks in materials to get a one button converter that runs several pieces of equipment at a full hp rating. The kit consists of 2 contactor, a potential relay, 2 start and 2 run capacitors and the wiring, switches etc. needed to hook it all up.

This is compared to: buying a rotary converter from a manufacture for 600 to 1200 bucks, buying a static phase converter that has a .75 % hp rating for 200 bucks or paying the power company 41,000 bucks to run 3 phase to my shop and then have around a 600.00 min monthly bill or;

The other option for 1-3 hp motors is the VFD or as my buddy calls the " magic boxes" for around 150 bucks that you plug in to 120-240 single phase and get 3 phase power out the other end plus have rpm control on the motor. I retrofitted a wet diamond glass grinder with a 3 phase motor and a VFD just to get the speed control and it works very well.