<Are these all water machines? There are some air-cooled versions that ar <probably reasonable. Water cooling isn't that bad. You could use heating compoents for pumps if needed and heat extraction from the water could be a automotive radiator with a blower to room air. Of cource the room temperature would rise but for short term ops that would work. <Yes, the 400 Hz would be a problem, almost as much as a cooling system (i <one went with a water machine - probably too big of a headache). Assuming you need 50kw, if it were say 10kw or less the scale of things drops to more managable proportions. Allison