Breaker Trips AFTER finished welding

Hi all. Quick question. I have a Lincoln Precision TIG 375 that was recently connected in my garage. I can weld without incidient using
this welder at various amperages. However, AFTER I finish welding (2 to 4 minutes after) - the breaker trips. This is currently a 90 amp breaker that I will be upgrading when I intend to use the full capacity of the 375, but for my current settings should be holding with plenty of cushion. I have never tripped the breaker DURING the weld or even within seconds after - only more than 2 minutes after.
Anybody seen this type of breaker tripping problem before and if so what's the problem/solution?
Thanks in advance!
Kevin
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The only possibility I can think of is that the wire or panel bus is overheating and the heat eventually conducts to the breaker to overheat it and trip it. Seems pretty unlikely though. I would just try a new breaker first and if it fixes it then file it under "Great Unsolved Mysteries I Have Known". I have a pretty big file of those.
Don Young

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Try a new breaker. I had one act up on me a while ago. It was the only thing that made any sense for my problem. Maybe yours too. Don could also have the answer if the panel is too hot. Use an IR temp gun on that issue.
Hope it helps,
Rob
Fraser Competition Engines Chicago, IL.

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Kevin,
Did you try to immediately unplug the machine after you finished welding? If the breaker still trips a few minutes after this, it excludes problems in the machine.
Circuit breakers are mechanical in nature and can go defect though. For a quick and easy solution I would simply replace it and see if it still occurs.
Peter.
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snipped-for-privacy@gmail.com wrote:

Does this machine have the power factor correction option? Power factor correction on transformer machines pushes the idle current WAY up. If the breaker was already warm from welding, the idle current into the power factor correction might be enough to pop the breaker.
Good Luck, Bob
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