# New VFD on Kondia Mill - Torque Compensation Parameters, Spindle Rotation Speed Display



## 4lathe (Nov 19, 2013)

I've put a Teco VFD on a 9B South Bend and just acquired a Kondia FV-1 mill that I put a 3hp Huanyang VFD on. The mill motor is 1.5HP.
The clutch clatters and I'm trying to avoid using backgears ( in fact I removed the cam ring on top of the head) so I need to deal with torque and hp issues at low rpm. At the lowest high gear pulley setting the 1800 rpm motor turns the spindle at 685 rpm. I occasionally need as low as 100rpm so that would mean running the VFD down to about 10hz. There are a huge number of seetings with regard to auto torque compensation , various curve set points,etc. I need to understand what the key ones to set are and what the gotchas are.
Of course the manuals are minimal and assume you know all the theory and rightfully so, but I don't.  Where can I get smart on this technical parameter decision making? thx
I've put a remote box on it to control run, stop, forward, reverse and speed. The VFD will display rotation in rpm's based on the motor rating of 1800 rpm. what I's like to do is apply a factor to that so that it reads the correct spindle speed based on what pulley I have it set on. I can't find a parameter for this in the list. I was thinking I could just  tell it that the 60hz rated motor speed was 685 ( top pulley position) and it would then read spindle rpm correctly. However I'm worried that messing with that parameter will screw up some other programming. any ideas?


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## rdhem2 (Nov 20, 2013)

Sir;
To display your spindle speed you will have to do as I did.  Purchase a small display that is actuated by a photo eye.  Then you will be dead on.  On the VFD you can see Hz, or percent or on some amperage draw or direct rpm, but I have never seen rpm after it goes though who knows what for speed reduction.

You may want to consider that running that slow you are loosing a lot of torque, even on torque compensated drives.  The other fact is motor cooling.  The motor cooling fan is running so slow the efficiency is gone.  Heat builds up, motor burns out, even though not overloaded.  I always set minimum speed on drives at 25hz so people can not screw themselves, unintentionally anyway!  When it does not go slow enough you get the mechanic to change gearing.  It is a engineering impossibility to have maximum performance at both the high and low end at the same time.


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## 4lathe (Nov 21, 2013)

I set the revolution parameter to 685 which is the 60hz speed rating for the pulley i'm on and the vfd displays rpm as a proportion of  set hz to 60hz. Now it may actually be a few % off one way or the other but not enough to matter for me. I upped the torque compensation at low rpm and in tests for the kind of thing i'm doing it seems fine down to 10hz. there is no cooling problem so far at all with the motor at 10 hz for 45 minutes at a time so I'll  be using that as my lower boundary.   I'm taking .010 cuts in mild steel with a 1/2 " end mill at that speed don't know the exact rate of feed but any way it works for me.


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