It is called a "Circuit Breaker".

As Roland said, your compressors will pull higher amperage on startup which will cause the voltage to drop and it snowballs from there.

Get a voltmeter that records high and low and see what the voltage drops to when the refrigerator starts.

Another good test is plug a heat gun or hairdrier in it. If the gen doesn't stumble when either of those are turned on your machine may have an issue with the inrush of current at startup. There is no inrush current with a heat gun or hairdrier.

Older generators make crappy power. I wouldn't run anything with any type of electronics in it off of a non-inverter controlled machine.

It appears you have a 2500 Watt or 20 amp available @ 120 volt.
or 10 amp at 240volt.
Use it and enjoy it.
If you plug something into it using an extension cord, remember to size the cord properly so as not have a voltage/amperage loss.
A good extension cord would be one that is at least 12 gauge wire, and remember the longer the cord is, the more voltage/amp loss.
A 100' cord is not good if you only need 20 feet of it, the loss it still there.
You plug your pancake air compressor into it and it runs it, but i'm betting if you use a 100' extension cord it will struggle.
----But you prolly already know this.:bigthink:

Thanks everyone, I'll continue to mess around with it some more. I suspect it's that they were trying to start up everything at once and it was too much for the old girl. I'll try some stuff and measure voltages. This generator also has its own volt meter built in as well.

Just stagger plugging them in. Odds are against them both starting again after.

As Farmall 450 says , stagger your startup , it would not be a 15amp 240v as that size generator needs some decent grunt to power it
I have a 3800watt generator and starting a fridge and freezer at the same time causes it to complain a bit , but stagger start no worries
Oz

Yeah I'm betting that's what my mom was doing, starting everything at the same time.