Finding a Single-Phase Motor to Use Instead of 3ph Motor

Have you considered an inverter? This will give you a three-phase supply from a single phase supply. It is perhaps less work than trying to source and fit a single-phase motor. However, in price terms, 7.2kW is big for both an inverter and a single phase motor.

OK. So how about hiring a 15-20hp 3Φ generator for however long the mixer is needed at the temporary place?

Does the mixer really need a 10 HP motor? If it does and you can not get away with a smaller motor, consider a DC motor with a DC drive. You should find a DC drive good for 10 HP that will run on a 230 volt single phase supply.

On the flip side, finding an inverter good for a 3 phase 10 HP motor that runs off of a single phase 230 volt supply will be hard to do and will be big bucks if you find one.

direct mechanical drive off an i.c. engine?

Just to put in my thoughts, how about pneumatics? There are a lot of high power air mixers out there. I am sure it would be much easier/cheaper to run a compressed air line. Lightnin, makes some great air power equipment. Not a true fix but just a suggestion.

Is a faster RPM a problem? Both Baldor and Marathon Electric have single phase, 230V, 10 HP motors available running 1725 RPM. Depending on what's in the mixer, you may need a slightly larger (12.5-15 HP) motor to drive at a higher speed.

Being that he said it is 400V it is highly likely to be 50Hz, which is what determines the speed.

Oops! I read 480 instead of 400. Thanks for setting me straight.

HP is HP is HP. You need a 10HP 230V 1 phase motor if you decide to go that way.

But first, check the motor nameplate. Some IEC motors are wound for 230/400V. You connect it in Delta for a 230V supply, connect it in Y (Star) for a 400V supply. If your motor is such, then all you need is a VFD which will convert the 1 phase 230V to 3 phase 230V without any other accouterments. That is the simplest method. But there is a catch; you must buy a 20HP rated VFD to do this, because you must derate the VFD by 50% for a 1 phase input or you will damage the conversion section.

If your motor is not wound for dual voltage operation, another alternative is to use a 1 phase transformer to step up your 1 phase 230V to 1 phase 400V, then get a 20HP 400V VFD and do the same thing. The package will likely cost you a lot more than just replacing the motor however.

No matter how you do it, realize that your power feed circuit will need to be 3.5x larger for a 230V 1 phase supply than it was at 400V 3 phase.

Hello, I just recently bought a converter kit from ebay and supplied my own 10 hp 3 phase motor and box and built my own single to three phase converter. The kit consists of 2 start up capacitors, 2 run capacitors, two definite purpose contactors, a switch and a potential relay. I am running a 10 hp compressor and a 3 hp iron worker from this set up and they work great. I have measured the output and I am getting nearly equal 230 3 phase voltage on all three hot legs. the kit was 75.00, I had the old motor and a electrical box so other than my time I had very little in what would have easily cost over 500.00 to purchase from one of the rotary phase converter companies.

pipewelder

Phase converter... I have been told Rotary styles are better than static models

go to this link on ebay "http://cgi.ebay.com/NEW-Static-Phase-Converter-12-15-HP-HD_W0QQitemZ280081830381QQihZ018QQcategoryZ633QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Anderson converters makes good,very economical phase converters. cost about $250 for 15HP lots less than another motor.

jacojan,

I dare ask a few basic Q's:

• What are you mixing with 1390rpm propeller?You mix liquids at~ 100 rpm
• Did you ever try finding out the minimum rpm you can do with?
• What was the active power needed at this low --but Sufficient --rpm?

If you had done with all above- you might have a surprise waiting:

You really needed 125rpm and 1/2 hp.

Maybe a 1 phase low power line would do!

Westinghouse Davenset Rectifiers used to make a simple static converter based on a pre WW2 design. It was mainly used for running 3ph equipment on farms with single supplies. It used resonant circuits to produce 2 phase shifted outputs which with the input produced a star connected 3 phase output. The load currents needed to be in balance for it to work properly so they were ideal for motor applications. They were built like tanks and lasted virtually for ever.

I think Hawker Siddley/Westinghouse sold off that company soon after I left in the early 80's so I don't if anybody still makes these units.