VFD slip compensation

[IHinIN]

I’m pulling out my hair trying to figure out an issue with my mill. I have a Willis 1050 knee mill with a 3hp motor running on a 5hp rated Lapond VFD. No matter how I have the parameters set, I can easily stall the motor taking a 0.050” cut with a 2” indexable endmill. We have Bridgeports at work with 1hp motors with more torque than I’m getting. I found a setting for slip compensation which describes what I’m experiencing but no matter what I set it at, it makes no difference at all. I even set the max allowable frequency to 120hz thinking that it couldn’t increase the frequency to compensate for slip. The upper limit frequency is set to 60hz which what the display shows with the dial turned all the way up on the VFD. I have the motor parameters correctly entered into the VFD.

Am I missing something? Thank you in advance for any help.

 

[tq60]

2 inch is a large cut.

Ours is only 1 hp, we often need back gear for some things.

Try back gear to see.

Your VFD may be sensing overload and shutting down.

Not slip but some other setting.

Sent from my SM-G781V using Tapatalk

 

[ddickey]

How's your drive pulley configuration?

 

[markba633csi]

Sounds like it could be a current limit or something similar- check parameters related to current
Does the VFD have an autotune mode?

 

[mksj]

I would make sure it is running in sensorless vector control, the V/F parameters would have no effect unless running under V/Hz. Need to run the motor Autotune if your VFD model has that ability (there are various Lapond VFD models). Assumptions are that you are running the VFD off of an RPC and at a fixed 60Hz, and using the Reeves drive for speed control, as such you should be getting full power. If you are running single phase it could be that your line reactor is current limiting, see what happens if you bypass it. Would check your motor parameters are correct, but not much to go wrong. I run a 3Hp knee mill with a Yaskawa VFD, have not had any power issues and that is running a vector motor from 20-200 Hz. If you continue to have issues with the VFD I would recommend looking at the Yaskawa VFD's, eBay link to a 3 phase input version which can be run in derated mode for single phase. O do not do any system installs with the generic Chinese VFD's just hit or miss as to working and typically poor performance.
Yaskawa GA50U2021ABM 240V 19.6A VFD (GA50U2021ABA is the standard, ABM is humidity resistant)

Yaskawa GA50U2021ABM 240V 19.6A VFD | eBay

This listing is for a Yaskawa GA50U2021ABM VFD, which has a voltage rating of 240V and a current rating of 19.6A. The item is being sold in a unit quantity of one. The brand of this equipment is Yaskawa and the model number is GA50U2021ABM. It falls under the categories of Other Electrical...

www.ebay.com

 

[woodchucker]

so first, 120hz is speed, not torque.
Where is your belt. I have mine set to the low end of the high range. That gives me torque and speed. If I need higher speed I have to move the belt. If I need a lot of torque I need to move the belt. So far I have not needed more torque, since I upped the motor from I think 3/4 to 2hp.
But I have needed more speed on small end mills, so I have had to use the higher speed pulleys.

 

[mksj]

I previously helped an individual do a Lapond VFD install on a mill, it was a pulley head on a new 3 Hp knee mill so the maximum frequency was set to 120 Hz (wouldn't want that with a Reeves drive, would just use 60 Hz). Attached the parameters and schematic. I do not recall any issues with the install, but my experience has been that the generic Chinese type of VFD's do not perform as well as mainstream VFD's and reliability has been an issue. Also the the output current ratings are a bit dubious with single phase input power on the larger Hp models.

 

[IHinIN]

My mill is variable speed Reeves drive. I have the frequency set at 60hz and I use the reeves drive to control the spindle speed. I run the 2” cutter 600-700 rpm which is near the low end of high gear. Changing to low gear and running at 500rpm makes very little difference.

I’ve tried to select sensorless vector control which is option 2 but when scrolling through the options it skips from 1 to 3. I think one of my previous parameter selections isn’t allowing me to select vector control.

I may have found why the slip compensation is not making a difference. It is used in Vector control mode and I have the VFD set to Common VF control. I’ll mess with the settings this weekend.

 

[IHinIN]

I changed the Macro definition from 0 to 5 and it now allows me to select Vector control.
When I select motor tuning, nothing comes up on the screen telling me that it’s performing the tuning.


It still easily stalls even with the slip compensation set at 200%. Would changing the proportional gain help? This is my first attempt at setting up a VFD so I’m just making wild guesses hoping something miraculously fixes it at this
point.

 

[den-den]

I am going to step on on a limb and guess that this may not be a programming problem. Can you verify the current and voltage to the motor is comparable to the VFD's output specs and to the motor's specs. I also suggest that you recheck the motor wiring to be sure that it is wired for the correct voltage. I am possibly full of !!!! but suspect that either the VFD is faulty or the motor is wired for a higher voltage.