Messages

21

General Mach Discussion / Re: burned a servo

« on: September 18, 2012, 03:52:24 PM »

Found this for the G320 surfing about;

FAULT INDICATOR:

The FAULT indicator is on while the drive is in power-on reset, the DISABLE input is held “low” or if the protection circuit is tripped due to a fault condition. All power MOSFETs are turned off and all internal counters are reset. The FAULT condition lasts for 3 seconds, and then self-resets to try again. If the protection circuit tripped it and the cause is not cleared, then it will immediately re-enter the FAULT state again and repeat the cycle.

There are two conditions that will trip the protection circuit. One condition is if a short-circuit occurs and current exceeds 20 amps.

The other condition is if the POSITION ERROR exceeds +/- 128 counts causing a break of the servo-lock. This condition can have several causes:

1) The loop settings are severely under-damped and the motor breaks out into oscillation.
2) Excessive motor load due to acceleration or workload.
3) The speed command in excess of what the motor can deliver.
4) The current LIMIT is set too low.
5) The power supply current is insufficient for the demand.
6) The motor is wired backwards, is broken or disconnected.
7) Encoder failure.

22

General Mach Discussion / Re: Antibacklash Nut

« on: September 18, 2012, 03:08:12 PM »

I think the bearings should be seated in thier respective housing. If they were to touch each other on the OD it should not affect performance. You will feel any unwanted friction much like Rich described above. He's got this friction stuff down to a science, lol. Good thing that you have all the parts after all.

Robert

23

General Mach Discussion / Re: burned a servo

« on: September 17, 2012, 10:00:03 PM »

So your not moving yet and you are overdrawing current...so does that mean the holding torque is causing the fault? What does Gecko say instigates the fault light? Has to be a short or overdraw of current right? Check all your conductors to ground(a wire touching, bare?). Keep disconnecting conductors, power off course until fault goes away. If you lift 6 & 7 and the fault is the same then lift the wires going to the motor. Something you take away will stop the fault. Not sure if the lack of impedence will cause issues on the drive so be real careful about the conductors going to the motor. Don't want you to cause addtional damage.

RG

24

General Mach Discussion / Re: Antibacklash Nut

« on: September 17, 2012, 04:44:12 PM »

You can contact the the bearing inner race but not the housing (rubbing)...sounds like you need a really skinny spacer in between to prevent interference from the nut and the outer housing. I dont think this is really anti-backlash (like between the nut and screw) rather anti linear play in the screw which would act like the former when changing direction of cut?

Robert

25

General Mach Discussion / Re: burned a servo

« on: September 17, 2012, 04:34:36 PM »

When you say applying 30% power, are you doing that on the drive dip switching for different amp ranges? Or are you trying different speed and acceleration settings in motor tuning or both? Sounds like a possible ground fault in the wiring in or out as you know the motor is good & drive is also good. I think checking wiring for ground faulting is not a bad idea at this point.

Since the basic breakout goes direct to Geckos maybe some damage happened back as far as the computer... pins 6/7? Roger stumped.

RG

26

General Mach Discussion / Re: burned a servo

« on: September 17, 2012, 10:54:28 AM »

You would think so but I have experienced that sometimes manufacturers don't like to offer too much outside of the component they sell. I guess that offering assiatance before or after a drive could be asking for trouble. In a sense it's not thier problem however I always hear good things of Gecko service. You eliminated the Z drive so that's good a good thing.

Give some diagnostic time to that motor. It was after all what got finger burning hot. When I checked the resistance across the leads of my motor it was around 4.5 ohm and niether was shortd to ground or motor casing. Simple check you can do to the motor which our old pro Hood was hinting at  possibly being the damaged. If you were to connect leads from a working motor to that Z drive everything else the same it should prove to be the motor or something before.

RG

27

General Mach Discussion / Re: burned a servo

« on: September 15, 2012, 01:47:17 PM »

Actually I do have a Hardinge dovetail conversion Servo 8000 lathe made in the 80's. She's a killer, works nice. I got a bunch of spare Pittman dc brushless motors with it. If these are anything like JQ's they are real simple, just 2 leads, a + & -. If there's damage, either a short to ground/casing or the resistance in the winding is low or high you should be able to measure it with a basic ohm meter and then compare to one of your other drive motors. If the motor overheated resulting in damage that could be pricey to replace as the Z is the big boy motor. I am not sure but repair of this type of motor may also be an option. Hope you can nail this down soon.

By monitoring and trying to participate in this thread and off course "Hood", I feel I learned allot and that more servo machines are in my future seeing how simple this is set up with the geckos.

Robert

28

General Mach Discussion / Re: burned a servo

« on: September 14, 2012, 06:42:30 PM »

Maybe the motor is damaged goods after all...is there 1 of the 5 motors than can be swapped out as a test? Everything the same just try a different motor. Working poor JQ to death here.

Robert

29

General Mach Discussion / Re: burned a servo

« on: September 14, 2012, 06:11:29 PM »

Reading thru this thread I understand JQ has verified the drives and the motor are all good but the Z position where any particular drive is connected still does not work. So what's left are the inputs and outputs.

30

General Mach Discussion / Re: burned a servo

« on: September 14, 2012, 04:04:16 PM »

On the zoomed in picture the blue terminal strip to the right with all the yellow & green wires are hooked to step and direction on each drive. If you look closely it looks like where the computer ties in from the port. You see a dark connector betwen the terminal strips below.  Compare signals coming from Z(terms 6 &7) and Y (4,5) ect. I bet something is corrupt off that so called break out.

I am a bit puzzled what the 2 boards in the middle do, 1 has a bunch of black capacitors (left) and the other looks like some sort of logic card(right, green board blue relays and chips). Maybe these are amplifiers...to handle feed back?? They tie together. Keep going!