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Offline Hood

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Re: burned a servo
« Reply #20 on: September 14, 2012, 05:47:00 PM »
Have you uncoupled the motor and tested it?
You have confirmed its not the computer or drive or anything up to there I think by swapping axis wires around and swapping drives. Think you said you had swapped encoders, so really that only leaves the motor.
Hood
Re: burned a servo
« Reply #21 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.

Offline Hood

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Re: burned a servo
« Reply #22 on: September 14, 2012, 06:17:54 PM »
Not sure if I am reading right but this would seem to suggest that the signals and wiring from Mach to drives are OK
Quote
I switched parallel cable wires 4/5 (which is the Y axis) with 6/7 (which is troublesome Z axis). Y still works fine, but Z still does the same thing.

The drive itself has been swapped and the problem persisted so drives not to blame.
Encoder has been swapped so its not to blame.

Motor has been tested on a battery charger which seemed to show it worked but possibly not as it may be moving but just not well enough to keep up with the position and speed requirements when the drive is running it.
Hood
Re: burned a servo
« Reply #23 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
Re: burned a servo
« Reply #24 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
Re: burned a servo
« Reply #25 on: September 17, 2012, 12:00:41 AM »
I had to walk away from it for a couple of days... I'll keep you guys posted.

What really frustrates me is the fact that I can describe the problem. Gecko won't accept enough limit to power servo to move Z. When I called gecko on this they didn't have an answer. Its not the gecko thats bad.. but something either up or downstream of the gecko.

I'd think that gecko would be able to tell me what this could be.
Re: burned a servo
« Reply #26 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
Re: burned a servo
« Reply #27 on: September 17, 2012, 03:37:41 PM »
It's a brand new motor. I knew old one was toast...I replaced it.

The problem is, I can't tune new one. The drive faults anytime I try and put more than about 30% power to it.

I've verified that the encoder works perfect, the drive works like it should, the new servo works like it should.

All other drives work like they should, and all 5 drives work off same power source.

I'm stumped!

Offline Hood

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Re: burned a servo
« Reply #28 on: September 17, 2012, 03:49:14 PM »
Hook the new motor up to the X drive, leaving Machs ports and pins as X, you will also have to connect Z encoder to X drive, see what happens.
Hood
Re: burned a servo
« Reply #29 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