question about duty cycle

[Mark @ Everlast]

At max amps, I think that the duty cycle fades to about 10% on the 211.

 

[HCJtractor]

The reason I asked is that I was welding recently (on 120 V as there was no 230V available) and it seemed to start losing power, still arcing, but just weak. I guess I needed to wait, but I just wondered if there was any indication (other than loss of welding power) like a overheat light, machine cut-off, etc. that would alert the user to wait. The manual is vague in this respect, and my machine was still running, no lights were on, so I was not sure if what I was experiencing was a duty cycle issue. The manual states that exceeding the duty cycle can damage the welder, but how do you know you have exceeded it if no warning lights come on or the welder does not have a shut off? When I am welding in a stop and go manner, it is hard to tell how many minutes are spent welding vs. how many minutes rest time. I understand duty cycle and know duty cycle is lower on 120V, but just wondered on my specific welder, if the machine protected itself automatically.

 

[Soundguy]

duty cycle tripping should stop the machine.. not make it limp...

soundguy

 

[Mark @ Everlast]

It is possible that the sensor was not working. It has a very low duty cycle at low amps while on 110V. But if they unit does not have a separate sensor, depending upon how it is setup, it may not be tuned for the 110V specifically...though you would expect it to from Miller. IF you were welding on an extension cord or something, the cord could be heating up and power input could have dropped. Or if your circuits were wired with aluminum, the same could happen.

 

[fabberd]

The reason I asked is that I was welding recently (on 120 V as there was no 230V available) and it seemed to start losing power, still arcing, but just weak. I guess I needed to wait, but I just wondered if there was any indication (other than loss of welding power) like a overheat light, machine cut-off, etc. that would alert the user to wait. The manual is vague in this respect, and my machine was still running, no lights were on, so I was not sure if what I was experiencing was a duty cycle issue. The manual states that exceeding the duty cycle can damage the welder, but how do you know you have exceeded it if no warning lights come on or the welder does not have a shut off? When I am welding in a stop and go manner, it is hard to tell how many minutes are spent welding vs. how many minutes rest time. I understand duty cycle and know duty cycle is lower on 120V, but just wondered on my specific welder, if the machine protected itself automatically.

That's not duty cycle that is doing that.

Mark hit on the head in his post. It's your wiring.
You're exceeding or at the limit of your electrical wiring or extension cord.

When you exceed duty cycle, the machine will stop welding. The fans will run to allow cooling, but you'll get no arc until it resets.

 

[HCJtractor]

thanks for the info!!

 

[Ford tractor]

duty cycle tripping should stop the machine.. not make it limp...

soundguy

"should" is the operative word. I've used several that would limp and give poor penetration for a while before finally stopping. It's VERY frustrating to have to go back and grind of the last 5 min of weld.

 

[Soundguy]

weird.. almost sounds like a thermal overload in the wireing.. vs a limp mode.

soundguy

 

[Mark @ Everlast]

As older transformer machines with out duty cycle interupts and units like the tombstone stick welders, the hotter they get, the weaker the spark.

There is another factory possibly, the contact in the switch could be corroded. The place where there is possibly the most resistance to flow of electricity is at the contacts in the voltage selector. If the unit is in a humid or corrosive environment, this could cause a weak spark once the contacts start heating up.

 

[Shield Arc]

This duty cycle thread is very interesting to me. I've never hit the duty cycle in any machine I've run. I must have lead a very sheltered life. I do pay attention to the duty cycle when buying a machine, but never hit it, and I've run machines at 500 to 600-amps for 10 to 12-hours days for months at a time. Had to replace the Tweco fittings in the leads every morning, and still didn't hit the duty cycle! :laughing: