Motor Chatter

[zeeway]

I am still in the setting up phase of my build, but I am stymied by a strange problem with my z axis motor. Several times now I have started up the machine and jogged all the axes - but the Z motor just chatters and the shaft does not turn. I take the motor off the machine and it acts the same way. Then after a while it begins to act normally.

I can turn the z axis screw by hand, so I know it is not jammed. The feed screw is a 1/2-10 five start with a Dumpster nut. My router is a Makita RF 1101, which is not super heavy. Drive is a Gecko 540. Acceleration set at 10 i/s/s/ and velocity is 100 ipm. The motor is a 380 oz in, so the torque should be adequate.

Anyone have any guidance for me? Thanks in advance.

[hemsworthlad]

I know this may sound obvious but will ask just to cover all base's. . . . You have wired it correct, it's not out phase is it.
If you havent already, I'd start at the begining and trace my way through then if all seems ok start swapping with other axis

Swapping with 1 of the other axis motors to see if it moves, that way you'll know if it's the motor or the drive.?
If it's doing it off the machine and moves when you change axis then it sounds like a miss wire or a knackerd motor to me.?

Cheers
Dean

[zeeway]

Dean, thanks for your suggestions. This motor came pre-wired with a DB9 end on it and the appropriate size resistor, so I think the wiring is okay - especially since the problem is not always present.

[hemsworthlad]

Originally Posted by zeeway Dean, thanks for your suggestions. This motor came pre-wired with a DB9 end on it and the appropriate size resistor, so I think the wiring is okay - especially since the problem is not always present.

Then I would be checking wiring for sure, it sounds like you have a dodgy contact or intermitant short occuring.?

[hemsworthlad]

Other thing to try with it being intermitant is swapping motors with another axis, then if at some point happens on that axis as well the you know it's got to be a wiring fault or motor problem.?

[jsheerin]

Assuming the problem does not follow the motor (so you know it's an electronics issues), it may be insufficient current capacity of the parallel port to drive the G540's inputs. I had this problem, and my fix was to install a dual parallel port pci card and make a custom cable that used some of the pins on both ports to get enough that worked to drive the G540. Details of how I tested and fixed it are in the Gecko drive forum. However other people have had a very similar issue and it was due to bad chips in the G540. Iirc, if you lengthen your step pulse or switch on Sherline mode in Mach3 and the problem goes away, this could be your issue. If you bought your G540 recently I believe they now test for that.

[zeeway]

Thanks for the suggestions. So far it looks like the culprit is one pin in the DB9 connection that had gotten pushed in...so that it was not making electrical contact. So my assumption that it could not be an electrical connection because it was wired with a DB9 plug from the manufacturer was dead wrong. Remind me to not "assume" the next time.