PowerFlex 40 vs. 70

What is the difference other than communications between a powerflex 70 and powerflex 40. They both seem to offer vector control. I have an application that has solids milling equipment and screw conveyors driven by a VFD. The last unit that we upgraded used powerflex 70 drives (the powerflex 40 was not available at that time). However I really do not see any reason not to use the powerflex 40 for this application (5-10HP).

Take a look at this webpage if you haven't already:

http://www.ab.com/drives/drives_hierarchy.html

Field oriented control (FOC) is a much higher performance control scheme than the sensorless vector control that the PF40 can do. This is especially apparent at lower speeds. If your application doen't require a particularly high level of performance the PF40 may work for you.

The only applications I have used PF40s on and have been satisfied with the performance are fan applications.

Keith

Powerflex drives

Thanks for the info. I guess I am behind the times in drive technology. I thought sensorless vector was the latest and greatest. Actually my only experience with powerflex 40s is on the conveyor drives in our packaging area. They work fine for this applications although I guess a powerflex 4 would also do the job.
Thanks again.

Originally posted by infineum:

I thought sensorless vector was the latest and greatest.

Click to expand...

Latest, yes. Greatest, no. Although you may get some argument on that point from DickDV.

The two big considerations between FOC and sensorless vector are low speed regulation/torque production and speed loop bandwidth. Both are better with FOC.

So in a nutshell if you will be running a constant speed with a reasonably consistent load sensorless vector is probably for you.

Be a little careful going from a PF40 to a PF4. The PF4 only has slip compensation and will be pretty sloppy.

Keith