Fans are usually a Commair Rotron P2B3, or PT2B3, or the slightly smaller diameter, but actually more far CFM, Pabst equavalent,
For Laser show sevice we always tried to boost the cooling using extra fans, but this takes some thought. Avoid ducting if you can because it drastically lowers the airflow. In an emergency, a Dayton 4C442 works, but is loud and can have annoying vibrations.
Make sure you have at least a short plenum between the fan body and the laser so the fan gets full drought and the airflow at the lid exit is less turbulant. I used to use 1-1/2 to 2 inches of PVC drainage pipe, One other thing, when bolting the laser to a baseplate, make sure the air truely exits the projector, and does not just loop back into the slots and heat things up inside the laser head. The better the cooling, the longer the tube life.
Use a 4 pin connector for the fan to satisfy the interlock, I've seen more then one laser lost to running without a fan, when the overtemp interlock switch is old and crusty, and fails.
There are many fans rated for > 250 CFM, but only a few that can start and obtain full circulation against a load of cooling fin pressure drop. . Rotron Patriot (PT2B3) is one of them.
Steve
Last edited by mixedgas; 06-12-2020 at 20:24.
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