Replies

1. 
   RickL | Dec 08, 2005 10:18pm | #1

   METHOD #2

   FOR FULL OR CLOSE TO FULL HP ~~ Configure as a rotary converter using Phase-A-Matic™ static unit ~~

   Full or close to full HP can usually be obtained by running a three-phase motor and PHASE-A-MATIC™ Static Converter combination as shown on the Installation Instructions. When running unloaded, the windings of the motor function as a rotary transformer or generator while consuming very little extra power. The Idler Motor needs to be at least 50% larger than the largest motor that you want to run to accommodate the higher starting current. A good quality 3600 RPM, three phase wye-wound, 220V motor is the best choice. 1800 RPM motors can be used on applications not heavily loaded. Used three-phase motors are inexpensive and readily available. When using this method, it is possible to run multiple machines as long as the idler motor is large enough to handle the largest load it would ever have at any one time. For instant reversing of the load motor, as in rigid tapping, the idler motor must be a minimum of twice the HP rating of the load motor, and perhaps more. The Static Converter is sized to the HP of the idler motor, not the load motor(s). Idler motor has to be 3 phase, wye type motors are best! Wiring has to be sized for single phase. Seperate circuit required. Sometimes scrapyards have them, depends on how good you are at finding stuff. Some folks are better off just buying new and others know the ropes. Too old a motor is posibly left alone. There's a bunch of other things too numerous to mention. I've set quite a few of these up over the years and I always find some new issue I never ran across before. A good motor shop or electrician can be invaluable. Top paragraph was from these guys... good outfit to deal with. http://www.phase-a-matic.com/StaticDescription.htm Rotary's are good for multiple motors. VFD's are more application specific and give variable speed, reverse, and can actually double the motor's rated speed. Good for drill presses, shapers, bridgeports. On motors under 1 hp you can run them on 120 volt with a VFD. great for a drill press.

   
   

   ---

   Edited 12/8/2005 3:30 pm ET by RickL

1. 
   woodenfish3 | Dec 09, 2005 04:29am | #3

   Are static phase converters easier to make?

   And, having only 2 phases running, and possibly 2/3 the horsepower, does it shorten the life of a 3-phase motor?

   I think it is not a great problem if a 3-phase 3hp motor only gives 2hp with a static phase converter, as long as it runs smoothly. 2hp is plenty and almost always enough.

   Single phase induction motors last years and years. Isn't running a 3-phase motor only 2-phase no worse?

   Edited 12/8/2005 8:30 pm ET by woodenfish3

1. 
   RickL | Dec 09, 2005 03:27pm | #4

   Buy a static, don't try to make one!!! It's the more complicated part to make. Contact http://www.phase-a-matic.com and they will guide you through the steps. Didn't you go to their site and do some reading? Statics are limited to specific hp ratings. Rotary converters are more versatile. VFD are a whole different thing depending on your needs. Start out by asking what exactly do you want to use it for and how do you think your three phase needs will grow!  There is no simple rule of thumb. Each application has specific needs to be met and while a static may be fine for one application it won't be fine for another.

2. 
   Napie | Dec 09, 2005 03:58am | #2

   Used three phase motors are dirt cheap. Call a local motor shop but do not tell them you are a hobiest or the price will go way up.

3. 
   mudman | Dec 09, 2005 09:05pm | #5

   Phase converter manufacturers are very competitive. It is hard to make one for less than you can buy it. And a good quality unit will give you trouble free service.

   Mike

4. 
   KesslerCraftsman | Dec 10, 2005 05:53pm | #6

   What kind of machine are you going to power.  I've got a 3-phase 3 HP Powermatic that I'll make a great deal on....just the cost of boxing and shipping the damn thing...

   lp

1. 
   woodenfish3 | Dec 10, 2005 09:47pm | #7

   Are you in Southern CA?

1. 
   KesslerCraftsman | Dec 10, 2005 11:34pm | #8

   Nope.  Dallas, Tx.  lp

5. 
   sawdustandshavings | Dec 11, 2005 11:14am | #9

   Hi,

   i, being one to save money have looked into making a converter but decided to get three phase installed to save the hassle.before that when i was looking on the web i remembered a man called Ian Dalziel, over in britain he is an excellent woodworker, he has a website where he has made wood planes, state of the art workbenches,snooker tables, tool cabinets and more. below is the link you need for the rotary converter plans.

   http://www.iandalziel.co.uk/rotary_converter.htm

   Sawdust.

6. 
   MStehelin | Dec 14, 2005 08:25pm | #10

   I know of a 10 hp motor 3 phase that has been sitting outside for 5 years..... Don't know if it works. I'll bet I could get it cheaply

7. 
   kesac | Dec 19, 2005 05:13am | #11

   The idler motor is 3 phase, and must be larger hp than the hp of the biggest motor you intend to start with it.  Long ago, (70s and 80s) I had quite a machine shop that ran off of a couple of phase converters.  I don't remember all the ins and outs any more, but I do remember that much.