[ianagos]

I’ve searched around and I cannot find any models that will do what I want at a decent price.

I’m looking for a 3hp vfd that can index the spindle and preferably take an encoder input for closed loop operation.

I was looking at the gs3 with the encoder card but I was told they will not index the spindle.

Budget is around $400 but as always the cheaper the better.

Single phase input or no phase detection circuitry is a necessity.

[Al_The_Man]

Most VFD's that have the encoder option is for accurate velocity control, for positioning you need a drive that can close the loop back to a PID controller, Mitsubishi etc sell spindle drives that will do this.
Al.

[ianagos]

Ok I don’t need indexing as in positional but just a single index for tool changing.

[Jim Dawson]

I got the same answer from Automation Direct regarding the GS3 units and with a lot (a couple of days) of playing around was not able to get it to index the spindle. BUT.. I was not using the encoder card on the VFD. I do have it operating on +/- 10V analog input from a Galil motion controller with an external 1024 line (4096 ppr) encoder. The speed control is rock solid from about 10 to 6000 RPM. This is the 7.5KW spindle on my lathe.

I have since purchased the optional encoder input card for the GS3, but have not had time to install and play with it. I'm almost done with my current project and will get back to that project in about a week or so. If you can wait for a bit I'll have an answer as to the possibility of doing this. If I am not successful with the GS3 then I am going to replace the spindle motor with a servo system.

If you look at the Black Max specifications on the Marathon site, they allude to being able to index the rotation of Black Max motors up to 3 HP with a VFD. But no other real information on this.

[ianagos]

I have no problem waiting I appreciate your help. I wanted to use a servo system but I cannot find an affordable one with my hp requirement that isn’t directly from China.