I was wondering what happens to a rotary engine when you rev it too high since there is no connecting rods or a crankshaft, or other parts that break on a piston motor. What happens, do the apex seals instantly fry and the excentric shaft snaps, or does the rotor break the sun gear it spins around??

 

The rotor gear can walk and jam against the side housing, or the teeth on the stationary gear can get damaged, or the bearings can spin/sieze, or the e-sheft can flex enough that the rotors contact the side housings...

...or you can do what I did. over 6200 the 3mm apex seals in pre'85 engines will start chattering. over 8500 it gets fatal. i exceeded 8500 by accident. next day, buzzing on an onramp, just as the tach needle swung past 6200 one of the apex seals elected to disintegrate.