Author Topic: Mig Welder Decision Time (Read 4139 times)

blarneyman · « **Reply #30 on:** June 15, 2005, 09:55:06 PM »

I'm no expert on welders but if I recall, when you change settings on the welder you are changing the amperage output. The output voltage is a constant, you can't change it. BUT, how long can you weld sheet metal without stopping (20-30 seconds + -). Throw the duty cycle out the window. The breaker will handle it for that long.

slugbug · « **Reply #31 on:** June 15, 2005, 11:18:30 PM »

Thanks for confusing the hell out of me guys. :wacko: Unfortunately I left my slide rule in my other pants

Bruce · « **Reply #32 on:** June 16, 2005, 01:49:43 AM »

Quote

I'm no expert on welders but if I recall, when you change settings on the welder you are changing the amperage output. The output voltage is a constant, you can't change it.

Thta's not how they work. The setting that you change to pick your metal thickness is a voltage adjustment. I think they go as low as about 12VDC. (and as high as 18VDC as Silas found out) The current is a result of the applied voltage and the resistance of the arc.

Bruce · « **Reply #33 on:** June 16, 2005, 02:05:03 AM »

Silas, the 1800W I quoted was the maximum that a household cct can deliver. The max available for the welder to use. But then according to the electrician it's really less than that for continuous (1500W).
The power consumed by the welder is determined by the welder's internal resistance.

From Mowser:
\"Any more would require them to have a heavier circuit to run them. Now 1500 / 18Volts is approx 83 amps. To get a true 90Amps the voltage would have to be 16.6.......\"

If you look further into the specs of the Miller welder (and all the other hobbyist welders), you will find they have a duty cycle. For my Miller, it is 20%, based on a 10 min cycle. So I can run it full out for 2 min, as long as I wait 8 min between welds. The cheaper brands will also spec a 20% duty cycle (more fraud) based on a 5 min cycle. Compared to the Miller, it only has a 10% cycle. Given this duty cycle, they will exceed the 1500W continuous max that Mowser quoted. Thus for short periods the Miller 135 will consume 18V x 90A = 1620W. But it's a bit more than that. There's the fan, wire drive motor, and gas solenoid.

Tom H. · « **Reply #34 on:** June 16, 2005, 05:00:17 AM »

let's see, hmmmm, screw-in fuses.

An early pure copper U.S. minted penny will hold more current than a later U.S. composite penny, which holds more current than a Canadian penny

B) .

silas · « **Reply #35 on:** June 16, 2005, 10:28:12 AM »

Quote

Silas, the 1800W I quoted was the maximum that a household cct can deliver. The max available for the welder to use. But then according to the electrician it's really less than that for continuous (1500W).
The power consumed by the welder is determined by the welder's internal resistance.

From Mowser:
\"Any more would require them to have a heavier circuit to run them. Now 1500 / 18Volts is approx 83 amps. To get a true 90Amps the voltage would have to be 16.6.......\"

If you look further into the specs of the Miller welder (and all the other hobbyist welders), you will find they have a duty cycle. For my Miller, it is 20%, based on a 10 min cycle. So I can run it full out for 2 min, as long as I wait 8 min between welds. The cheaper brands will also spec a 20% duty cycle (more fraud) based on a 5 min cycle. Compared to the Miller, it only has a 10% cycle. Given this duty cycle, they will exceed the 1500W continuous max that Mowser quoted. Thus for short periods the Miller 135 will consume 18V x 90A = 1620W. But it's a bit more than that. There's the fan, wire drive motor, and gas solenoid.

gotcha. thanks bruce.

so, with a welder on it's lowest setting (12VDC) and taking into account the added resistance of the fan, spool motor, and gas solenoid...the welder should be able to complete it's duty cycle without tripping a circuit or WOOFING a wire, correct?

but, as the voltage is adjusted higher the resistance is greater and thats when your duty cycle goes out the window and your wires start to WOOF?

thanks for all the help guys.

Scratchy · « **Reply #36 on:** June 18, 2005, 10:41:57 AM »

Just to add fuel to the fire....

Like Bruce, I bought a MIG back in the 80's when they first came out.
It's a \"Dual MIG 120\" that welds 3/16\" no problem. The electrical rating is 16 Amps @ 120V.
If I crank the Voltage & Speed, there is no way to weld for more than 10 or 15 seconds before a 15A breaker will blow.

My solution was to get a 50 foot chunk of 3 - #10 'cabtire' & graft a dryer plug on one end & a 15A duplex receptacle in an 1110 box on the other.
Now I can weld all day at full power (I also but a fan in the end to keep the windings cool - increase the duty cycle).
It's a much simpler solution that re-wiring your house, as long as you have a dryer outlet close to your garage & it's not laundry day when you are welding...

slugbug · « **Reply #37 on:** June 23, 2005, 10:56:13 AM »

fedex delivered my Hobart Handler 135 this morning.

Next thing I want to get is an auto darkening helmet
I wonder if those Solar brand ones are any good :unsure:

Tom H. · « **Reply #38 on:** June 23, 2005, 06:08:53 PM »

I have one of them cheapie autodark solar jobbie do's from harbor Freight. $60 (?) and well worth it.