Would a phaser have problems with overheating? This issue hasn't been raised during any altercations in the show that I know of - the operator keeps firing the weapon without a worry.
General knowledge of heat based weapons would indicate that there must be some threshold where the weapon would overheat. Has this ever come up in any of the series?
That's why they have phaser coolant: to stop overheat from happening. In the TOS episode Balance of Terror, there's a leak in the phaser coolant with disastrous consequences.
Slightly less canonically, according to the novel Vendetta, every time a type-2 phaser is fired at level sixteen, there is an automatic six-second cool-down period, otherwise the phaser will overheat and possibly explode.
