Vfd And Very Low Torque

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On my lathe I have replaced my motor with a 3 phase 230 volt 1 hp Leeson motor. I am running this through a VFD from Automation Direct with 120 volt input, model is GS2-11P0. I have gone through the manual to set the VFD parameters where I think they should be and I can give further details. I was running my belt from the largest pulley on the motor to the smallest pulley on the spindle which was giving me about 2000 max RPM.

This is a recent CNC conversion and I have only been cutting plastic as I familiarized myself with things.

On to steel. On a .002 facing cut on 1.5" rod at 600 RPM running from the centre of the piece outward the lathe stalled at about the half way point. Increased the speed to 800, still stalled out. Backed everything off, increased speed to 2000 RPM, used my hand around the rod and I was able to stop rotation fairly easily. Then changed the belt to smallest at the motor to largest at the spindle, which gave a max of about 750 RPM and I could still hand stop the rotation. This thing just has no torque.

Changing the P2.00 setting from 00 general purpose to 01 high starting torque did not make any difference. When I changed this setting to 02 fans and pumps the motor did not turn at all.

First of all, do I have a problem or is this all I can expect from this motor/VFD combination? If I do have a problem where might I look to try and resolve it? All suggestions appreciated. Also I can provide further info on my settings if that will help. Thanks.

Dennis
 
Any error codes?
How long of a run from the panel to the drive? How's the input voltage when the motor is under load? Did you set the maximum current output to match the motor?
 
What is the torque rating of the motor. A vfd can't really improve the torque of a motor all that much and at speeds higher than 60hz you will suffer from reduced torque if the voltage is not increased with the frequency.
 
Is the motor expecting 220 volts? Low voltage to motor can cause less torque. Is their a 110v terminal layout for the motor?

Stuart
 
There is a problem here somewhere, a 1hp motor should produce quite a bit of torque. Does the drive trip on over-current when you stall the motor? I agree that it would be wise to verify output voltage (check it at 60 hz). Also if this motor can be wired for other voltages, verify it is wired correctly for 220/240.
 
Wow, South Africa, USA and England - what a brain trust to call upon! So I shut off the VFD and went poking around in the electrical connections but could find nothing there. So I turned everything back on thought and I would redo my hand breaking test, put the RPM at 600 and grabbed the bar. Whereas previously I could easily stop rotation now I could not. The only thing I can think of is that turning the VFD off and on allowed some change in the settings to take place.

Or............ I once took some electronic item in for repair and the fellow checked it out and pronounced it fit and functioning perfectly. His diagnosis "It just wanted to go for a walk."

Thanks for the responses and turning my head away from the VFD settings.

Dennis
 
In addition to the above comments, make sure the max output current is set to the motor nameplate value (P0.01)
 
There are 2 styles of drives variable torque and constant torque, constant torque is what is needed for a lathe. Constant torque is used in industry for conveyer belts as the load increases the drive will compensate for it. Variable torque drives are for fans pumps etc. where the loading stays the same. I have never set mine up on my constant torque drives but I know there are multiple parameters to set.
 
Automation Direct has excellent phone accessable support staff who seem to be specifically oriented to their VFD product line. I have the same 120 vac input unit you have & they were clearly helpful diagnosing a minor difficulty that I had experienced.
 
You stated that you have the motor pulley on the largest size. That mechanically reduces the torque at the spindle. Change your pulley arrangements to give you a 1:1 ratio. Then you will see the same torque at the spindle as you have at the motor.
 
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