daytona
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| posted on 21/11/02 at 09:56 PM |
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welding info
have got the chance to buy a tig welder with AC/DC output for £200, the only problem is its 3 phase. Does anyone know if its possible to get it
converted to single phase.
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interestedparty
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| posted on 21/11/02 at 10:06 PM |
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I'm going to guess that it would need a different transformer at least. You would probably do better getting one of those devices that converts
single to three phase, trouble is, quite expensive
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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ProjectLMP
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| posted on 22/11/02 at 04:06 AM |
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What amperage does it use? TIG welders generally use more amps than MIG. Professional single phase transformer based powersupplys can easily pull
100amps. A phase converter may be usable but they get really expensive for high current applications. You may not be able to supply the amount of
current it requires from a domestic socket.
Home of the Astronomicalcost Mid engined LMP project
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David Jenkins
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| posted on 22/11/02 at 08:55 AM |
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quote:
Originally posted by interestedparty
I'm going to guess that it would need a different transformer at least. You would probably do better getting one of those devices that converts
single to three phase, trouble is, quite expensive
John
A 3-phase converter wouldn't work - they take the single phase and 'fake' the other two with inductors & capacitors. When they are driving a
3-phase motor there is no problem, as the motor itself forces the phases into reasonable shape. You also have to buy a converter to match the motor
size reasonably closely to aid this process.
The converter also gives a 'bump start' to help a 3-phase motor start before the phases are properly sorted by the motor.
The only way you could consider doing it is to use the converter to drive what is called a 'pilot motor' - a large 3-phase motor which spins without
a load - which means that you get a reasonably realistic 3-phase supply permanently from the output.
(guess who went through all this when he bought a large 3-phase lathe  )
As a guide, my converter cost over £200 and will only supply 15A starting current and under 10A running current - you won't run a welder off that!
So the answer is - keep looking for a decent 1-phase welder...
rgds,
David
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Viper
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| posted on 22/11/02 at 03:05 PM |
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quote:
Originally posted by daytona
have got the chance to buy a tig welder with AC/DC output for £200, the only problem is its 3 phase. Does anyone know if its possible to get it
converted to single phase.
Do you know what the machine is? ie Miller, Kempi etc? if you can,t use it i might be interested...
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daytona
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| posted on 24/11/02 at 12:03 AM |
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not sure of the make although i know its american, capable of 300A with foot control
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Wadders
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| posted on 24/11/02 at 12:32 AM |
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I've also just bought a 3 phase lathe,and have been researching homemade rotary converters,try these links they may help.
Good luck
Al.
http://home.att.net/~waterfront-woods/Articles/phaseconverter.htm
http://home.att.net/~chipmaker/projpage.html
http://www.practicalmachinist.com/cgi-bin/ubbcgi/Ultimate.cgi
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daytona
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| posted on 24/11/02 at 12:35 AM |
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Hello wadders, what hp is your three phase motor as i have got single to three phase inverters for sale but only up to 1hp
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Liam
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| posted on 24/11/02 at 02:49 PM |
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Just a thought - you could find the other two phases at your local sub-station, and run a couple of extension leads to your house. "Nobody would
mind!".
Sorry, I didn't even take my coat off...
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Wadders
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| posted on 24/11/02 at 05:48 PM |
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inverters
Hello wadders, what hp is your three phase motor as i have got single to three phase inverters for sale but only up to 1hp
Thanks for the offer Daytona,but unfortunately the lathe is 2 hp.
Cheers
Al.
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interestedparty
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| posted on 24/11/02 at 06:58 PM |
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If one wanted to buy a three phase lathe or other piece of motor driven machinery, wouldn't it be easier to just change the motor for a single phase
unit?
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Wadders
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| posted on 24/11/02 at 07:11 PM |
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If one wanted to buy a three phase lathe or other piece of motor driven machinery, wouldn't it be easier to just change the motor for a single phase
unit?
John
Valid point John,and correct to a degree,but single phase motors are between 30-50% less efficient than the equivelent 3 phase units,so in my case i
would probably need a 3hp single phase motor,these aint cheap new,and hard to find second hand, then theres the hassle of mounting the thing.
I reckon i can build a rotary phase converter for peanuts,as large 3 phase motors ar worth nowt second hand.
ATB
Al.
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bass
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| posted on 24/11/02 at 07:47 PM |
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i run a 7HP motor off a converter, i did have an old converter that you had to run an other motor to make up the 2phs, but, it was a pain . starting
up one motor just to use the b/saw, s/grinder, lathe ect. 3ph machines are a lot cheaper to buy s/hand plus the motors are smaller and last a lot
longer. didnt like starating the compressor under load it burnt the motor out
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stephen_gusterson
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| posted on 24/11/02 at 08:02 PM |
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quote:
Originally posted by Liam
Just a thought - you could find the other two phases at your local sub-station, and run a couple of extension leads to your house. "Nobody would
mind!".
Sorry, I didn't even take my coat off...
Actually, Liam, it wouldnt be as hard as that.
Three phases run down every street. Some houses are run from each phase, but I dont know what the 'firing order' is. But if you had a few friendly
neighbours and long extension leads, you could give it a try.
This isnt a serious suggestion BTW!!!!
atb
steve
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bass
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| posted on 24/11/02 at 08:20 PM |
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some big houses, pubs, shops have 3ph
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Wadders
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| posted on 24/11/02 at 08:46 PM |
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some big houses, pubs, shops have 3ph
So do all lamposts,know what i'm saying?
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