[jcarrz1]

Hello,

I am working to restore functionality of a mill that had some water damage on the electronics. This includes the PC controlling the mill with Mach 3 and a parallel port. Luckily, I was able to get Mach 3 running on a second PC and controlling the X and Z axes of the mill.

The Y-axis, just like the X-axis, is powered by a G320 controller. I also have two new G320X controllers. The X-axis is fine; it works with the G320 controller that got a bit wet and has dried. The Y-axis moves and blows a fuse rapidly on its old G320 controller with the same wiring, the G320 X-axis controller, and a new G320X controller.

Before the water damage, the mill worked well with the G320 controllers on X and Y.

The fuse is 5 amp, and the controllers are running at about 67 volts.

The Y-axis motor starts moving immediately when we power the geckodrive controlling its motor. This happens on both the G320 and the G320X. The fuse blows shortly after it starts moving. No fault light is present on the controllers. I am using the same wiring, including the resistor between the encoder and error pins, probably the same wiring that worked before it was transported and water damaged. The same wiring is used on G320 and G320X.

I am suspicious about the wiring for this Y axis. The motors are visually identical on X and Y, but when examining the electronics after they were exposed to water, we noticed that the ground wire for the encoder was not connected for the Y-axis. Is there any way this was correct? Or did it fall out during transport? (the mill had been transported and not used for a few months.)

One other peculiar thing is that the G320 that originally controlled the Y axis had a little loop between the "Common" screw terminal and a connection on its PCB just below. Was this just due to a broken screw terminal solder joint? or is it a trick I don't understand?

Here are some photos. The controller labeled "C-6" on top (with its own closeup photo) is the X-axis. The photo below shows both the X- and Y- axis controllers in their water damaged state. You can see the suspicious wire on the bottom left G320, there is a combo green-black-ground twist that is not connected anywhere. The tip of that twisted combo is visible just above a perpendicular black wire. The little red loop I called "peculiar" is visible here too.
https://goo.gl/photos/QzVswPKwJHsR2vWCA

Thanks for your help.

James

[Al_The_Man]

Did you check the motor for grounds with a meter?
Also check the motor with an automotive battery and see if it works OK in both directions.
Al.

[jcarrz1]

Did you check the motor for grounds with a meter?
Also check the motor with an automotive battery and see if it works OK in both directions.
Al.

Can you elaborate on your first suggestion? Do you mean check the housing of the motor for a grounding issue?

Thank you! I will try these things tomorrow afternoon. Is there any reason an issue with either of these tests would cause the motor to run right away?

[Al_The_Man]

Run away is usually caused by loss of feedback, check to ensure there is no continuity between motor leads and frame, ground.
Al.

[jcarrz1]

Run away is usually caused by loss of feedback, check to ensure there is no continuity between motor leads and frame, ground.
Al.

Hi Al, the motor wires are isolated from both the red "common" wires used in the last pin of the controllers and the ground of the control box. Is there anything else I can try? I am with the mill now and able to troubleshoot.

Edit: Wow, I just noticed that the two motors for the wires have a lot of resistance, just enough to make my multimeter beep. How weird that it has ever moved. We are tracing the entire wire run now and looking for shorts. How could the motor have even moved with this much continuity?

[jcarrz1]

Hi Al, the motor wires are isolated from both the red "common" wires used in the last pin of the controllers and the ground of the control box. Is there anything else I can try? I am with the mill now and able to troubleshoot.

Edit: Wow, I just noticed that the two motors for the wires have a lot of resistance, just enough to make my multimeter beep. How weird that it has ever moved. We are tracing the entire wire run now and looking for shorts. How could the motor have even moved with this much continuity?

There is some more information. In my original post, I discussed how the ground wire for the encoder was removed (and I thought it may have happened during transport.) Now, I have noticed that the controller only powers on and does normal Fault light behavior when that wire is not installed. When the wire is installed, no lights appear. This confirms to me that the wire is meant to be unplugged from the controller, I guess.

The wire is the ENC- wire, and in our mill it is a twisted combination of 3 wires: Black insulation, Green insulation, and uninsulated. On the x-axis, it is connected.

Why would the mill have worked in the past without ENC-?

Now, the Y-axis motor controller powers on properly with a short Fault light blink. Whenever we jog the Y-axis, the fault light appears again. The wires on the motor do not show any voltage going to the motor, and no sounds come from the motor.

Thanks!

[jcarrz1]

One more follow-up, did a lot of troubleshooting today. This is a video of how the controller behaves (and a picture showing the ENC- wire unplugged). Remember, the controller doesn't power up with that wire inserted to Encoder Ground (6).

https://goo.gl/photos/LHSG2yxwwysFNyT27

to me it looks like how the motor controller should behave with a properly-connected sensor and without a motor connected. Which is weird, because the sensor is wired incorrectly (?) and the motor is connected. Is there any way to test the motor? The "warn" light came on when i moved the axis manually (but never the fault). It might have felt like the motor was fighting me? if so, very weak.

Thanks in advance for any help. The motor no longer runs away, and no longer blows the fuse.

[Al_The_Man]

The motor should posses very low resistance, just a few ohms, if high resistance then there is a problem, did you perform the automotive battery test?
Al.

[jcarrz1]

The motor should posses very low resistance, just a few ohms, if high resistance then there is a problem, did you perform the automotive battery test?
Al.

Ok, that sort of thing I was wondering if it was safe to do on the motor without a controller. We will try it. Are you sure the continuity between the leads isn't a characteristic of our servo motors? It happens on the other identical x axis motor too, and seems dependent on rotation.

Also, I found a note about a 470 ohm resistor in the g320x user manual. I think the encoder is externally powered for the y axis and not the x. I'll try adding the resistor. It would make sense if the y axis encoder is externally powered because the controller seems to behave as if the encoder is properly connected. Would connecting all 4 wires of an externally powered encoder without the resistor cause the g320x not to power up at all?

[Al_The_Man]

DC brushed motors should show the resistance of the armature plus the brushes, which even on low power motors is a fairly low resistance.
I have never used Gecko products.
Al.