I'm not endorsing anything here just looking for the general consensus on application of a frequency drive to a screw. I think this was argued out on another forum sometime back. A customer made the statement the other day that such and such has a screw machine out that is using a frequency drive. Now I thought why would you need a freq. drive on a screw, unloading capability is already there, maybe the benefits of lower inrush on start but that is a waste of a good drive if just for that. Maybe a fixed speed or limited unloading screw that uses plug valves instead of slide valve. Working on finding who, what, when. You fellas running any screws on freq. drives? A centrifugal I could see, they can make an enormous efficiency gain if controlled right and coupled with lower condenser entering temps. But a screw I don't see it, maybe the fellow was thinking vsd but in reality was a solid state starter? Solid state starters are available on most of the major players screws already though so that tends to cancel out that theory.

Mike Hopkins