Stuart.......
The compressor is a British made SIP Industrial.
http://www.alexander-mills.co.uk/sip/compressors/compressors.htmThe motor is a 3 phase 5.5 HP running a 2-Stage, 2 cylinder compressor that will fill the 52 gallon tank within a minute of starting up.(Just worked out it is a 52 NOT 40 gallon tank!)
Running a pressure sand blaster the unit can go a few minutes without cutting in, and that is running at 100 psi.
The specs on the unit are 25CFM.....free air delivery.
The 3 Phase 415 Volt power supply we have in Australia is a big difference to running a 5 HP single phase 110 Volt motor there in the states.
That combined with the 2-Cyl, 2 Stage pump, moves and compresses the air much more efficiently than your normal air compressors.....hence the much bigger output.
Just more efficient from the same amount of horsepower.