I would suspect your swtitch is becoming too hot and reaching maximum thermal capacity, under which condition the device will shut itself off. Log files will show you this and if you had Syslog server configured and used message would be sent there, and/or potentially SNMP traps if these are configured and used.
I suggest you look a temp of switch and check that the fans are both working properly and not clogged with dust. This is most common situation to cause what you are experiencing.
I suggest you look a temp of switch and check that the fans are both working properly and not clogged with dust. This is most common situation to cause what you are experiencing.