Duty Cycle Protection

[JWELD]

If the duty cycle of any given machine (Miller) is exceeded,is it protected by the reset or an overload circuit of some kind??

Thanks

[Paul Seaman]

When the duty cycle is surpassed and the machine is overheated a thermostatic switch opens the circuit, output stops and the cooling fan continues to run at this time wait 15 minutes and reduce output {amperage,voltage or duty usage} and continue.

This is a partial extraction from the book on the mm210.
Hope this helps,

[MAC702]

When my only machine was a MM130XP, I use to hit its duty cycle all the time on some jobs. I'd just do some other work for a few minutes, and when I got back to the machine, it was ready for a few more minutes of welding. That was quite some time ago, and I had no choice but to be hard on that awesome machine. It is still in the hands of a friend who uses it occasionally.

I've hit the duty cycle of my MM175 once after nearly 20 linear feet of welding at full power with .030 and 100% CO2. I only had 2 inches of bead left on the project and had to finish it after dinner. The MM175 has an indicator light so you don't spend a few moments trying to figure out what you've done wrong. It's good to avoid the duty cycle, but it's usually something I don't even need to consider.

[JWELD]

Mac:
When you say "hit" the duty cycle, do you mean the machine stops and can I damage the machine?
Thanks

[MAC702]

Originally posted by JWELD
Mac:
When you say "hit" the duty cycle, do you mean the machine stops and can I damage the machine?
Thanks

I seriously doubt any damage was done to the machine when it cut out. I would think that the overtemp cut-out is built to cut out BEFORE anything gets warm enough to be damaged. But we can add an extra measure of protection by just knowing that we are going to be going at maximum and not do more than a 30% duty (3 minutes out of 10) on a MM175, or 20% on a MM135, or whatever applies to your machine.

But mine were extraordinary circumstances at the moment. Which is what these machines are designed for: light duty with occasional maximum output. If you need to routinely do what would be near-maximum for one of these machines, than you seriously need to consider a bigger machine.

[Paul Seaman]

If you do hit the duty cycle on that machine it will shut down the wire feed and arc will stop. There is no damage to the machine as long as you let it cool and don't start welding prematurely, the book for my machine says 15 minutes. That is the gospil according to miller and that is good enough for me, and I like you don't want any preventable damage. Since the investment is significant we all want the longest life possible out of our dollar spent.

You'll be OK if you just let it cool down.