I want to build a 3ph converter

[LD1]

I'd stay away from the cheaper 5hp "compressor duty" motors.

They have a lower service factor, lower start up torque, and probabally wouldnt last long. If the 3ph you have is truly a 5hp motor, you need something more like this one
https://www.surpluscenter.com/item.asp?UID=3152011911493752&item=10-2391&catname=electric

Not to mention that the motor you currently have is probabally only 1700rpm and most compressor duty motors are 3450rp.

But a $300-400 motor might still be cheaper than a phase converter.

 

[dex3361]

I believe what you are looking for is a rotary phase converter. Take a look at
Building a Three Phase Converter or just search google for rotary phase converter. You'll find lots of other hits.

I have seen a few of the homemade 3 phase converters only they weren't as well assembled as the link shows but they all did a pretty good job. They worked just as the post indicates. If I had several machines and needed 3 phase I would build a converter but if I just had 1 machine I would get a new single phase motor. If I needed speed control I would use a VFD (Variable Frequency Drive)

 

[jenkinsph]

I have seen a few of the homemade 3 phase converters only they weren't as well assembled as the link shows but they all did a pretty good job. They worked just as the post indicates. If I had several machines and needed 3 phase I would build a converter but if I just had 1 machine I would get a new single phase motor. If I needed speed control I would use a VFD (Variable Frequency Drive)

I'm with Randall on this, if this is your only need for 3 phase then spend the money on a new single phase motor or VFD. It would be unfortunate to spend the money on the converter only to have the old 3 phase motor fizz out.

 

[tommu56]

We use a lot of actech ac vfd's at work thay ar simple and bullet proof but wont go to 5 hp on single phase they stop at 3hp but that might do unless you are going to run it hard.

http://www.actech.com/cgi-bin/site.pl?smv~r

tom

 

[luscsmith]

The best way to buy industrial controls--low prices, fast shipping and superior service.

These people have a good selection, pricing and tech support.

Scott

 

[Iplayfarmer]

Iplayfarmer - unfortunately, the motor that you picked is a 3450 RPM motor.
I am almost positive that an engine lathe will have a 1725 RPM motor. Also, if you go from a three phase to a single phase motor, the starter will have to be up sized due to the higher current rating.

The least expensive option is to consider a variable speed drive, (inverter). It will provide soft start as well as speed adjustments. Drive technology has advanced far enough to really lower the cost.

You should be able to pick up a 5hp drive that will take 230v single phase in and 230v three phase out for under $400.

If you can find an phase converter for that price it would be worth it due to being able to use in on other 3 phase stuff in the future. I still think that a single phase re-power is the way to go unless there is a collection of 3 phase equipment you want to power.

I see motors on Craig's List all the time around here for $50 or so. That's another option.

I figured that the motor I picked wouldn't be a perfect fit. I just linked to the first one I saw to demonstrate the concept.

 

[jcaron2]

Buying something is obviously the easier choice, but building a rotary phase converter is actually very easy. I didn't check them out, but the links already posted will almost certainly tell you how. If not, a quick Google search will show you.

The basic idea is to buy an inexpensive 220V 3-phase motor and power it up with single-phase 220V wall power by generating the third phase with a couple of motor-run capacitors. Once the motor is up and running, it back-generates all three phases very cleanly regardless of how much current you draw (up to the rated HP of the supply motor). The rated RPMs of the supply motor (usually 1750 or 3450) are irrelevant since you're not mechanically connecting the shaft to anything. You just have to make sure the motor can be wired for 220V, not just 440V or 600V.

A good friend of mine has powered his entire commercial machine shop from a home-made rotary phase convertor for over 20 years. It uses a 100-HP motor. The first guy in in the morning turns it on, it runs all day long, and the last guy to leave shuts it off.

 

[alltoys]

My main problem is finding stuff here in Canada, US not such a problem but bringing across the boarder is murder. Free trade my azz!!

I have three pieces or will soon that have 3ph motors the largest is the 5hp motor the other ones are 3hp. Going by some of the designs I can build one here a rotary type for about $200 CDN. I spotted a 10hp three phase motor for $20 as it needs new bearings.

End result with a rotary type converter out put is 308V or 318V roughly which will run the 1750 rpm motors already on board.

 

[spk64]

Buying something is obviously the easier choice, but building a rotary phase converter is actually very easy. I didn't check them out, but the links already posted will almost certainly tell you how. If not, a quick Google search will show you.

The basic idea is to buy an inexpensive 220V 3-phase motor and power it up with single-phase 220V wall power by generating the third phase with a couple of motor-run capacitors. Once the motor is up and running, it back-generates all three phases very cleanly regardless of how much current you draw (up to the rated HP of the supply motor). The rated RPMs of the supply motor (usually 1750 or 3450) are irrelevant since you're not mechanically connecting the shaft to anything. You just have to make sure the motor can be wired for 220V, not just 440V or 600V.

A good friend of mine has powered his entire commercial machine shop from a home-made rotary phase convertor for over 20 years. It uses a 100-HP motor. The first guy in in the morning turns it on, it runs all day long, and the last guy to leave shuts it off.

A rotary phase converter is an easy solution if you can find another 3 ph motor cheap. I had one gathering dust that was used to power and old 3 ph industrial sewing machine. I start up the converter with a pull rope. A quick pull to get it spinning then plug it in. Once it is running I have a 3 phase power source. Yes, I could have purchased a new motor but I had the motors and it did not cost me a dime. That is in my small workshop.
Here is a link for the basics on a rotary.
In the main shop I had 3 ph power at one time and have several pieces of equipment lathe, mill grinder, air compressor. The utility company decided it was in their best interest to shut down everyone in our rural community on 3 phase by charging and outlandish min. monthly rate . So a converter was needed for the shop. I use a static converter to start the lathe since it was best matched to the HP of the lathe. Once it is sitting there idling it functions as a rotary and I can start up the mill or compressor. Works great for the small jobs that only get ran on that equipment. This only cost me the $120-$150 for the static converter.

 

[escavader]

The cheapest, easiest way in my opinion would be to repower the lathe with a single phase motor.
$133 + Shipping from Surplus Center...
https://www.surpluscenter.com/item.asp?UID=3152011911493752&item=10-2390&catname=electric

I'm sure there are other sources too where you could find the perfect motor.

Perhaps the current motor he has can be wired up different [meaning changing the sequence of wires in the motor],i see this alot on SAWMILL equipment at my work.If there is a plate on it that tells you how to wire for different phases its doable.
ALAN