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15th Jun 2006, 10:04 PM #1
Reducing welding power supply problems
Yes its me again
I am aiming these comments at those folks who may have power supply problems to their new or old welding machine. If your are just thinking about purchasing a welder check this piece out first and you may possibly avoid some gross annoyance and frustration in getting the bastard the weld properly. Hopefully the electrical types will be watching like a hawk, so I’d better not make any mistakes. If I do make an error guys feel free to correct me.
The stuff I refer to is, say when the run is a shortish bead and the breaker drops out.
I am going to try and explain what the causes are and hopefully how to minimise or avoid these problems.
Plug wise our single phase 240 volt welder machines come in 2 flavours 10 amp plug and 15 amp plug. 15 amp jobbies are fitted with the wider earth pin plug so outright dickheads don’t stick em in 10 amp plugs. However, dickheads do this by filing pins down and sometimes buildings burn down and cables burn out.
Generally the salesman who sold you the machine does not give a toss if the machine can’t perform the way you thought it should. A ten amp machine should work well from a 10 amp GPO as a fifteen amp machine should work well from a 15 amp plug. You take it back and they check and say there’s nothing wrong.
Problems can arise when you attempt to weld when there is a peak loading on the supply line. The symptoms are, the arc not seeming as strong at a given setting and the tendency for the breaker to trip after only a small run of bead at max amps.
First port of call is to check how many volts you are getting at the GPO. What comes out of your welding machine is a result of what goes in it. In Queensland at least power supply is not permitted to drop by more than 10%, so it’s possible that at times, one may only be receiving 216 volts at the GPO. This can be a result of you living at the end of a supply line and/or every one using energy gobbling devices around you especially in peak hour. Obviously the cure is to avoid welding at peak hour.
Please take care when using the multimeter on a live GPO If you are not sure get a competent person to do it. Get it wrong and you can be electrocuted or at least fry a good multimeter.
Another point to check is the duty cycle which should be displayed somewhere on the welder. Those marked at 25% or less will give you grief in the above described conditions. Some improvement may be gained for those already with a low duty cycle by assisting ventilation with a fan directed at the cooling vents of your machine. If you are using an extension remember the more length you have the more current loss you will suffer.
Get an extension cable made up to the length you will need, with no excess.
If you are flush with cash you can buy an inverter welder as they operate with less heat loss than the above mentioned transformer choke welders.
At this point to close off , I would like to offer a little caution those DIY errs who may have a very old stick welder. They may have found that this stick welder turns their old electrical meter box readings backwards. This can happen with old welders and old power meter units. If this is the case your welder lacks power factor correction. It’s a bit hard to explain here but a result can be that it overheats your power circuits inside the house and could burn it down. I have only seen two machines like this in 40 years. I can’t be plain enough here but if you are aware of it and continue to do it, you may be likely to lose your house through fire and possibly any insurance cover. Connect with your friendly local sparky for more on this as it can be fixed.
I hope this makes your welding easier for some of you
Grahame
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16th Jun 2006, 12:41 AM #2Originally Posted by Grahame Collins
Originally Posted by Grahame Collins
Originally Posted by Grahame Collins
Originally Posted by Grahame Collins
Originally Posted by Grahame Collins
What happens is that if you have a thing running at 1.0 power factor, it uses say, 5A. That means it's consuming 1200W.
Take the same thing with an ugly power factor power factor, and the thing starts sucking 10A for the same power output. You don't notice it at the appliance, but the wiring starts hurting.
The problem is that these old welders are 15A, and there are planty of old meter boxes full of re-wireable fuses that will keep on ticking for long enough to let the wiring catch fire.
A suitable capacitor will fix things, and you won't notice anything at your welder either.
Originally Posted by Grahame Collins
At 100v my welder would not function at all.
Installed a 200V circuit and changed the lead into the welder, now welds like a champion.
Schtoo, used to be a sparky. Still am on paper.
(BTW, 3 phase welders are another jump again. You can get the same thing as what a 15A welder puts out, but it only sucks 5A and does it much easier than the lower current suggests.)
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