These Edwards ACX RADIAL air cooler (cooling fan units) work with Edwards nEXT 240, 300, & 400 model turbomolecular vacuum pumps, they operate on 24 VDC input power, have 3 meter leads, and have Edwards part number B580-53-170. This radial fan is to be installed on the side of the turbo pump. (See far right graphic above) An air-cooling fan is used to cool a turbo pump when a suitable cooling-water supply is not available or for pumps used in a mobile pumping system. The air-cooler is an enclosed electrical fan and fixing bracket assembly which is easily fitted to the side of the pump by a bracket bolted to the base of the pump. 
The nEXT turbo pump drive has a 3-way connector socket on the side of the pump with 24 VDC output intended to drive this fan or a vent valve. This connector may be concealed by a black protective cover. This cover can be removed by levering with a small screwdriver. A mating plug for this connector is supplied with the turbo pump, once assembled this plug connects directly into the pumps 3 way controller connector on the side of the turbo pump. The nEXT-240, 300, & 400 turbomolecular vacuum pump user's manual and nEXT pump accessories manual is available for download in PDF format below.