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Offline Hood

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Re: burned a servo
« Reply #40 on: September 20, 2012, 02:57:13 AM »
I may have missed it so I will ask again, have you tried swapping the motor and encoder wires from the Z to the X drive and jogging the X axis?
Hood
Re: burned a servo
« Reply #41 on: September 20, 2012, 11:09:28 AM »
I would take Hood's advice. It's just one more step in the elimination process, it might lead you to solve the problem. He has an end game...your checking pins from X versus Z I take it.

Otherwise go back to the manual and the conditions for a fault:

Are you exceeding 20 amps, basic overcurrent? You'll need to measure somehow.

Is POSITION ERROR exceeding +/- 128 counts causing a break of the servo-lock. If so;

Conditions 1-3 are generally during a run so disregard for now

4) The current LIMIT is set too low. Not sure where your at with this?

5) The power supply current is insufficient for the demand. Don't think so your not moving yet but only drawing holding current

6) The motor is wired backwards, is broken or disconnected. It's new but could plus be reversed with minus on motor end?

7) Encoder failure. Most proable but you say you eliminated this with replacement known to be good?

The troubling part is that the fault should only come on for one of the above conditions so you have to figure out which one it is. If you lift the encoder wires power off does the fualt stay on?





Re: burned a servo
« Reply #42 on: September 20, 2012, 05:00:17 PM »
there's a limit pot that you turn on the Gecko drive. The Gecko isn't allowing me to turn up this pot switch enough to allow the servo to move the Z axis, the limit controls the voltage and or amps going to the servo. Even at rest if I turn the pot switch up past about 30% A fault light comes on the Gecko.

Not changing any settings in Mach at all.

Stupid question...but you first turn the unit on it's stable then you increase the current limit to ~ 30% and fault comes on right? What happens if you leave the pot lower than 30%? Will the motor turn in jog? According to the manual (item # 4) the fault should light with too low of a pot setting... not higher. It sounds like its working backwards. It's like you should have the pot set up higher before you power up. Reaching a bit but a thought to consider.

Offline BR549

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Re: burned a servo
« Reply #43 on: September 20, 2012, 05:20:52 PM »
If you do what hood asked you should find your answer.  Pick a good axis then move the bad axis  wiring and motor over to that drive. IF it runs ok then it is the drive if not it is either the servo/encoder or wiring.

Just a thought, (;-) TP
Re: burned a servo
« Reply #44 on: September 22, 2012, 12:11:24 AM »
FIXED!

I reversed polarity on servo motor... go figure

Offline Hood

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Re: burned a servo
« Reply #45 on: September 22, 2012, 04:32:40 AM »
Wrong polarity would normally make a DC servo run away but maybe the Geckos are smart enough to detect that and fault the drive?
Hood
Re: burned a servo
« Reply #46 on: September 22, 2012, 12:38:11 PM »
FIXED!

I reversed polarity on servo motor... go figure

Good job, I am happy for you. You did admit in the beginning that you were electrically challenged, lol.

The manual tells no lies brother:

6) The motor is wired backwards, is broken or disconnected. It's new but could plus be reversed with minus on motor end?

Rob

Re: burned a servo
« Reply #47 on: September 23, 2012, 01:41:10 AM »
And FYI.. the servo did have red and black leads coming off of it... I just assumed they were correct.
Re: burned a servo
« Reply #48 on: September 23, 2012, 01:50:28 AM »
What motor polarity is correct is determined by how the encoder is connected, as well as what rotation you consider to "correct".  You cannot go purely by wire colors.
Regards,
Ray L.
Re: burned a servo
« Reply #49 on: September 23, 2012, 01:55:43 AM »
On my old servo that I ruined... the red and black were correct.

Just hoping this thread could help someone else in the future.