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General Mach Discussion / Retrofit problems.
« on: August 27, 2006, 08:06:09 PM »
I am working on a Tree Knee Mill retrofit, and am having some problems 
.
I am currently using Gecko 320’s, and the existing motors. The existing motors I believe are 90v Baldor’s, and they have 1000 line encoders. The x is a timing belt on a 2-1 pulley, with the encoder on the 5TPI ball screw. The Y is connected by a timing belt on a 2-1 pulley, with the encoder on a timing belt with a 1-1 pulley to the screw.
At first setup, x and z gives me a maximum of 115 IPM, and seem to run fine. Y does not run at all. The gecko just faults out, and resets. After talking with Brian Barker, It was decided that the issue was either the encoder, or power to the encoder. So I then connected an external 5V supply to the encoders, and got the Y working intermittently for a while, but it randomly faults out. After looking at the encoder pulses on the scope, we found that they were very low voltage. We took the encoder apart, and found it full of oil! In cleaning the oil out, I think that we ruined the encoder. So we installed a different encoder (500 Line), with better, but still not good results.
With this encoder, the gecko only faults either when first starting, or when changing directions. This has been repeated over and over again, with very slow speeds. I am confident, that this is not a tuning issue, as the fault occurs even at the slowest acceleration setting, and also given the same basic setup as the x, it should work with the same settings, right?
Now I have the gecko’s current limit set all the way up, so the motors are getting all the current that they can. This mill also has handles on the screw. I have found that I can break the “motor lock” with very little force. The y will break free easier than the x.
Do you folks think that my problem is that the motors are weak?
Now as I said, these motors are 90V motors. The geckos can only take a maximum of 80v. I have a 50V transformer, and I’m getting about 72VDC out. Could this be the problem? Do you lose holding torque by lowering the voltage? I am not sure, but I would think that when the drive is locking the motor, I should not be able to rotate it enough for the gecko to fault. It seams that evryone hear, likes gecko's, but I am wondering if we should have gone with the rutex drives?
Based on the manual, that came with this mill, with the old drives, This mill got 250ipm+ rapids, so the PC, is the limiting factor here for speed.
Any feedback, that you folks can give is greatly appreciated.
Thanks
Chris Seeley
.I am currently using Gecko 320’s, and the existing motors. The existing motors I believe are 90v Baldor’s, and they have 1000 line encoders. The x is a timing belt on a 2-1 pulley, with the encoder on the 5TPI ball screw. The Y is connected by a timing belt on a 2-1 pulley, with the encoder on a timing belt with a 1-1 pulley to the screw.
At first setup, x and z gives me a maximum of 115 IPM, and seem to run fine. Y does not run at all. The gecko just faults out, and resets. After talking with Brian Barker, It was decided that the issue was either the encoder, or power to the encoder. So I then connected an external 5V supply to the encoders, and got the Y working intermittently for a while, but it randomly faults out. After looking at the encoder pulses on the scope, we found that they were very low voltage. We took the encoder apart, and found it full of oil! In cleaning the oil out, I think that we ruined the encoder. So we installed a different encoder (500 Line), with better, but still not good results.
With this encoder, the gecko only faults either when first starting, or when changing directions. This has been repeated over and over again, with very slow speeds. I am confident, that this is not a tuning issue, as the fault occurs even at the slowest acceleration setting, and also given the same basic setup as the x, it should work with the same settings, right?
Now I have the gecko’s current limit set all the way up, so the motors are getting all the current that they can. This mill also has handles on the screw. I have found that I can break the “motor lock” with very little force. The y will break free easier than the x.
Do you folks think that my problem is that the motors are weak?
Now as I said, these motors are 90V motors. The geckos can only take a maximum of 80v. I have a 50V transformer, and I’m getting about 72VDC out. Could this be the problem? Do you lose holding torque by lowering the voltage? I am not sure, but I would think that when the drive is locking the motor, I should not be able to rotate it enough for the gecko to fault. It seams that evryone hear, likes gecko's, but I am wondering if we should have gone with the rutex drives?
Based on the manual, that came with this mill, with the old drives, This mill got 250ipm+ rapids, so the PC, is the limiting factor here for speed.
Any feedback, that you folks can give is greatly appreciated.
Thanks
Chris Seeley