CHANGE 3phase to 'single phase 60Hz ...???

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hughesdevco
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CHANGE 3phase to 'single phase 60Hz ...???

Post by hughesdevco » Sat Mar 16, 2002 5:07 pm

Hi There! does anyone out there know of any way to operate a 3 phase tool on single phase? ie: Electric Hoist is 220/240 60Hz 3 Phase I want to operate on 220/240 60Hz 'single phase' I know there are phase inverters for sale but they are sooooooooo expensive! ANY IDEAS???? THANKS !

russlk
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Re: CHANGE 3phase to 'single phase 60Hz ...???

Post by russlk » Sat Mar 16, 2002 6:01 pm

I don't know the accepted way to do this, and not knowing the power rating of the motor, I can only give an approximate method. for a 1 HP motor, try connecting one side of the 220 line to phase A, connect the other side of the 220 line through a 200uF AC capacitor to phase B, and connect the same side of the 220 line through 27mH to phase C. If it runs backward, reverse connections to B & C. The inductor and capacitor have to handle 3 or more amps. Please let me know if this works!

hughesdevco
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Re: CHANGE 3phase to 'single phase 60Hz ...???

Post by hughesdevco » Sat Mar 16, 2002 7:29 pm

Thanks Russ....what you say makes perfect sense to me...I'll give it a try the 1st of the week and for sure let you know the results..by the way the one lift is 1 1/3 hp. Have a great weekend! Mel !

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Re: CHANGE 3phase to 'single phase 60Hz ...???

Post by Lee McVey » Mon Mar 18, 2002 3:19 pm

Shifting the phase angle 120 degrees forward and 120 degress behind is what has to occur. If you use passive components such as capacitors and inductors, you must still maintain rated voltage on the phantom phases within a few percent and the motor must rotate wihin about 5 percent of its synchronous speed to avoid overheating if it is loaded substantially. So, to achieve 120 degree phase shift, you will probably need RC and RL networks to achieve the shifts, plus some voltage boost on the two artificial phases to compensate for network losses. I'm guessing that its a 4 pole motor (most common), so its unloaded free-running speed should be 1800 RPM before gear train reduction.<p>You might want to check and see if the manufacturer makes a single phase motor replacement. It might be least costly in the long run.

bodgy
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Re: CHANGE 3phase to 'single phase 60Hz ...???

Post by bodgy » Mon Mar 18, 2002 3:29 pm

I note someone on ebay is auctioning off a couple of phase converters - last night the bidding was upto U$45.00 - retail U$1500.00<p>
bodgy
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MrAl
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Re: CHANGE 3phase to 'single phase 60Hz ...???

Post by MrAl » Mon Mar 18, 2002 7:27 pm

Hello there,<p>Another idea would be to see if your power
company would be able to supply you with
three phase electric power. Im pretty sure
this is available at the power line on the pole.<p>It cant hurt to find out...<p>Good luck,
Al
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Droidwerkz
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Post by Droidwerkz » Sun Jan 13, 2008 5:41 am

i discussed dropping three phase from the pole to my shop , it comes with a hefty fee!

just an idea here, but:

Why not find a single phase reversible ac motor with the same housing standard as the 3 phase hoist motor (industrial motors typically use standard flanges, and are known by ASME standards such as 56C and others) , just remember that when you run a lower voltage , you will draw higher current and require larger wiring /relays etc.

Dean Huster
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Post by Dean Huster » Sat Jan 19, 2008 10:31 am

About the only time an electric utility is willing to run 3-phase to your shop is if you are going to be using a LOT of power and the 3-phase line is already running by your property. It costs them three times as much to serve 3-phase as it does a single phase, but if you have a really heavy load, supplying you from a single phase could unblance their line enough that they'd rather serve up three.

Seems that the suggestion to swap out the motor with a single-phase unit (especially if it's 240v) is the more practical solution.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

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MrAl
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Post by MrAl » Sat Jan 19, 2008 3:40 pm

Hello again,

Wow, talk about bringing up an old subject :smile:
The last post before this month was back in March of 2002...wow!
If he didnt find the solution by now i feel sorry for him :smile:
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b1miller
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Post by b1miller » Sat Jan 19, 2008 4:08 pm

Depending on the size of your 3 phase motor, one option is to use a VFD with a single phase input. Allen Bradley and others make VFD's with a 240V single phase input that will produce 240 or 480 3 phase output. The only limitation is that they typically may not handle more than a 2-3 HP motor.

dyarker
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Post by dyarker » Sat Jan 19, 2008 8:09 pm

"Wow, talk about bringing up an old subject"

It happens often with new users.
Dale Y

Dean Huster
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Post by Dean Huster » Mon Jan 21, 2008 5:38 pm

Actually, it happens often with us O.F.s, too. Failing memory, not looking at the OP date, etc.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

Droidwerkz
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Post by Droidwerkz » Fri Jan 25, 2008 3:19 am

YEAH . i didn't look at the dat of the orgiginal post ...sorry guys!!!(and gals) :lol:

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