PRS Daily Maintenance Question

[James M]

Hi,

Got my shopbot up and running. Now all I have to do is tune it up a bit.

My question is about item 3 in the PRS daily maintenance checklist. It says:

3) Check rack/pinion/motor/shaft relationship by rapidly pushing and pulling the carriages near each motor. X1, X2, Y and Z. Adjust motor mount and/or tighten set screws. A slight clicking sound should be heard, but no movement (over a few thousandths) should be present. Adjust if needed.

I was under the impression that rapid moves my generate a current in the motors and damage the controller.

Can someone clarify this procedure for me.

Thanks,

James

[Tim Lucas]

Hi James,

Just make sure the controller is powered on and you will not likely move the carriage unless there is something loose like a pinion gear.

So perform step 3 powered up - but yes if you are not powered up and push the carriage the motors will turn and produce current (not good)

[Brady Watson]

This should be performed with the control box on/motors energized with the tool at rest.

Yes, the motors become generators when an axis is pushed quickly with the control box off. This is not as much of a concern on newer tools as it is for pre-2005 ones. There is some protection built in to prevent things from getting fried...but don't over do it.

-B

[James M]

Tim and Brady,

Thanks for your help.

James

[James M]

Brady & Tim,

Ran the test and found that the X car motor furthest away from the table zero point did not lock up like it should. What is the best troubleshooting method to nail down whether it's the motor or the electronics?

[Brady Watson]

Are you staying that you can push the gantry on the back side of the tool & it gives no resistance like the front?

Loosen and drop the X2 motor (front side @ Y0).

Pull the X1 motor off (the one on the back side of the tool) and rest it on the table. Power up the control box.

In keyboard mode (k or SK) press the right or left arrow key. Does X1 turn?

If it doesn't, then you either have a bad connection (check all wiring from motor to drive) or a faulty drive.

If yes, then hold the pinion with a gloved hand and move it again. Can you stall the motor? If no, everything is OK. If yes, then you are either running on one coil (broken wire somewhere) or the drive is flaked out.

Sometimes the connectors (Geckos) can get corroded and need to be pulled and reseated to get them up again. Does the X1 driver power LED light up?

Do you have Oriental RBK drivers or Gecko drivers? Post a pic if you are not sure.

-B

[wayne_walker]

James,

You have a private message.

Wayne

[James M]

Brady,

Thanks for your suggestions. I found that I indeed had a bad connection. The motor was fine. However, there is some play in the X1 motor that is not in the X2 motor so I'll pull the X1 motor and check the pinion.

Thanks,

James