Author Topic: Rotary Phase Converters  (Read 1500 times)

Offline NC Driver

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Rotary Phase Converters
« on: February 04, 2011, 01:30:07 PM »
We're adding a couple of 3 phase pieces of equipment to the wood shop and are looking now for a rotary phase converter.  The motors are 7.5 HP on a shaper and 5 HP on a table saw.  First question is how big a unit I need to purchase.

Are the TEMCo rotary phase converters any good.  http://www.phaseconverter.com/#Rotary-Converter  They seem to be popular and the price is low (hence the popularity?).  I am wondering if they are undersized for the job they need to do. 

What about Desco units?  I cannot find much on the web about them, but there is one about 1.5 hours away that is a 15 hp for $500.

Any others we should consider?

Thanks in advance

Mark
Mark

Offline Uncle Buck

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Re: Rotary Phase Converters
« Reply #1 on: February 04, 2011, 02:31:10 PM »
PAGING OCG! PM message him, that fella will know all about this, right down his alley I asure you.
You boys better hold on cause i'm gonna have to stand on it!

Offline NC Driver

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Re: Rotary Phase Converters
« Reply #2 on: February 04, 2011, 02:55:04 PM »
PAGING OCG! PM message him, that fella will know all about this, right down his alley I asure you.
Will do.  Thanks

Mark
Mark

Offline goodfellow

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Re: Rotary Phase Converters
« Reply #3 on: February 04, 2011, 05:04:31 PM »
This chart might help narrow down your search a bit.

http://www.phaseconverter.com/rotary-converter.sizing/

Offline D.Spencer

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Re: Rotary Phase Converters
« Reply #4 on: February 12, 2011, 07:49:25 AM »
Build your own! it's not too difficult and it will be better tuned  http://www.metalwebnews.com/howto/ph-conv/ph-conv.html
« Last Edit: February 12, 2011, 07:59:24 AM by D.Spencer »

Offline rvannatta

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Re: Rotary Phase Converters
« Reply #5 on: February 15, 2011, 05:16:24 PM »
Build your own! it's not too difficult and it will be better tuned  http://www.metalwebnews.com/howto/ph-conv/ph-conv.html


I quasi built my own.   I  bought a 'box'   with the necessary capicators and switch, and then supplied my own
idler motor.

I have a 10 hp  idler motor,   and   a  7.5 hp lathe and a 5 hp lathe motor.   I can actually run both of them at the same time.

It shouldn't really be this way, but.......     the idler motor needs to be larger than any other motor you are starting,
and  the overall wiring needs heavy enough to cover the total load.

the reason I can get way with two lathes combined larger than my idler motor is that I start them one at time
and oncerunning the second to start joins the first to start as an idler motor.     Anyhow it works.


But the basic rule is that the idler/phasce converter capacity should be larger than your motor load.   I don't know what the smart guys would thing of starting multiple motors in sequence....   but it is my impression that if the motors are not loaded to the max, the bit issue is only getting them started.    If they get started reliably, the rest doesn't matter.


Capacitors aren't particularly expensive,  but if you overload one you know it right away  <grin> because it always
is announced by   a  bright flash,  a loud bang, and a room full of smoke.     If you encounter this sequence either do not repeat the what ever you did immediately before this,  or buy bigger capacitors.

the latter advice may have something to do with why my cobbled up phase converter works.   I bought the capacitor box that was suppose to be sized for the 10 hp motor,   but obviously wasn't,   as after I ordered larger 'start caps',   the flash, bang, smoke sequence did not repeat itself.     I just don't reccommend sitting on your capacitors while testing them out unless you want to impress someone with your new found ability to pass smoke SHF

Offline D.Spencer

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Re: Rotary Phase Converters
« Reply #6 on: February 16, 2011, 12:00:52 AM »
I built my own also from that article in my last post. Mine is manual start meaning you have to manually hold on the start circuit till the idler gets up to speed- this works best. Mine is also set up to drop the whole circuit if power is interrupted for some (any) reason and I am not in attendance-don't want anything burning up due to a lost phase. I run a 5 hp idler and have a close to same hp on my lathe. My horizontal mill is 460V, 3 phase, so I use a set of transformers (3) to boost the voltage-Yes, the motor is not a multi-tap- first thing checked. It is true that the motors you bring on line adds to the total hp you can start untill you reach the limits of fuses and wiring.

Offline rvannatta

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Re: Rotary Phase Converters
« Reply #7 on: February 17, 2011, 09:10:58 PM »
Well, I set my overall wireing to handle 50 amps on the 3 phase side and use  the same 50 amp  nema plugs that
are on my Lincoln Vantage welder.    My lathes and the shaper are all  'plug in'.     and I have made a 3 phase extension cord which I can also use for my tool post grinder.

However if I need to work things off the welder which is truck mounted,   I can with the extension cord run any of my machine tools off the welder just as well.    It's one of the really nice features of the Lincoln Vantage.   it comes standard with
a 50 amp  220 1 phase plug and a 50 amp  3 phase  plug.   and will output 17-19 kw through the 3 phase plug.

The Garage Gazette

Re: Rotary Phase Converters
« Reply #7 on: February 17, 2011, 09:10:58 PM »

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