Phase Converter

[David E.]

Hi,
Here in UK the largest motor on single phase is normally 3 or 3.5 hp, so to run a decent size power hammer I would need a phase converter to give me 3 phase
from a single phase supply. Does anyone here use a converter to run a 4kw/5hp
or bigger motor from a single phase supply and are you happy with it??

[LDW]

A buddy of mine has a machine shop behind his house and has been running end mills, lathes, and surface grinders for years with no problems. This web page has a similar set-up to how his is set-up. Don't know if it would do any good in the UK though.

Building a Three Phase Converter

[David E.]

Thanks LDW, apparently power hammers put a heavy load on the supply at start up and I just wondered which converters worked and which didn't. david.

[JWBIRONWORKS]

David,
I run 2 converters in my shop, one is a small 1hp and is dedicated to a hydraulic pump. been in service for about 7 years, the other is a 7.5hp that I use to run several pieces of equipment. it has been in service for about 3 years.
I built both and have had no problems with either one. in my opinion rotary is the only way to go for shop equipment. I'm not powering any compressors with it but end rush has never been a problem.

John Bennett

[metalmaster1766]

i built me a rotary phase converter a few years ago, it is just a 2 hp motor, they work great and are very easy to build, mine cost me about 2 hours worth of time to assemble, that was after collection the capacitors, which i got from old outside central A/C units

i plan on building a bigger one someday

the thing about a roto phase is, you idle motor, which is in fact the phase converter itself, can run whatever size motor it is - if you get a 5 hp 3 phase motor and turn that into your roto phase (thats what i call them) you can run a 5 hp machine with no problems, now say you have 4 machines all with 3 phase motors, 1 or them is a 10 hp motor, you can run that by turning on the roto phase (5hp) plus starting another 5hp motor and let it just idle, then you should be able to turn on and run a 10 hp motor and run a full power

the hp adds up with all the idle motors

thats why i need a bigger roto phase, mine is 2hp i have a 7.5 hp cutoff saw, i hafta turn on all the 3 phase machines and let them idle so i can get my saw to work, i onl;y have 1 other 2hp motor and several 1hp motors, so i hafta turn my roto phase on, then the 2hp motor, then 3 other 1hp motors to get the saw to work, it just about max's out my amps by doing this, but it does work

you can buy one for several hundred dollars, or build one for cheap, and if you are good and resourceful at collecting things, you could build one for less than $25 maybe even free (like i did)

oh yeah, most small motors (like my 2hp) doesnt need a start up capacitor, most (not all) will start to turn just by adding the 2 single phase 120v power to it, then you use the capacitors to even out the 3rd leg of 120v to as close as the others as possible

bigger motors need the startup capacitors, or a pony motor and belt to get the bigger motors to start spinning, you can use a pull rope to start it spinning and then turn on the power, then is will start up,

ill look for the link i have about them, the guy lives here in Cincinnati, he sells a disc on ebay on how to build them, it is like $2 and he can email a down loadable file or for $5 he will send a C/D he also will help out as best he can thru email if you have problems building one

i bought him breakfast (from Mcdonalds) and he gave me a disc, has lots of info on them
i would try to send it to you but it has some type of copy write thing that makes it impossible to do


Ron

[arftist]

When you say decent size, what do you mean ? my 35 kg mechanical hammer runs very,very well on 2hp.

[stevet]

I have a static converter that i got second hand , think its 11kw, i regularly run a 8hp motor with it,
Steve

[steveh]

i went and spoke with the outfit that built my phase converter on pricing other ones.they dont make them anymore,too old school.,they now have frequency drives.they are programmable and are cheaper than the converters,very cool little units.

[Chris Pook]

I run my Nazel 3b which has a an oldschool 10hp motor with a phase converter.

No issues with it. Just make sure you have a good single phase power source.

[David E.]

Thank you all for your replies and experiences, I am now much more informed as to how I should proceed. I have a dedicated 240 volt single phase and I also have what is called here "split phase" or 2 phase it is still single phase but 2x 240 volts making 480 volts. I only use this for my 300amp stick welder.
I want to power a Sahinler with a 4kw motor (5.5 hp) 3 phase.
I have noticed that you commonly have 5hp motors on single phase in US where the largest we usually can get here in single phase is 3hp 240volt.
I had not considered making my own, (electrics are the devils work to me )
but I shall look again. Thanks again.
David

BTW Chris what is the size of your converter to run the 10hp and is it a rotary?