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Author Topic: What's setting free the magic smoke? Help please.  (Read 9064 times)

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What's setting free the magic smoke? Help please.
« on: May 14, 2014, 03:57:23 PM »
Good to see you guys.
Briefly, after swapping some bearings, my x axis only made a quiet whine, and no movement. Checking I found about 4 wires had come loose from the choc block connector to the motor. Putting them back in, one touched the framework and I realised i had left it energised when there was a crack crack from the direction of the control box.
Checked the fuses,  :( They were ok. Swapped the Gecko's about to see if one of them was the problem. Crack. Magic smoke from the good Gecko moved to the X axis. So now I am 2 Geckos down, call it £250 on the night, and don't know what the problem is or how to track it down. Suggestions please?
And it's always when there's a big rush on, and also, I can't seem to think straight, or I would have tested the suspect drive Gecko on another axis...I think it's panic.
suggestions welcome.
james

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Re: What's setting free the magic smoke? Help please.
« Reply #1 on: May 14, 2014, 04:47:24 PM »
Ohm out your motor windings  to see if there is a short.
Hood
Re: What's setting free the magic smoke? Help please.
« Reply #2 on: May 14, 2014, 05:07:18 PM »
Thanks Hood.
I did continuity, if that isn't enough I can ohm, but ;
8 separate wires,
Continuity between
ORange / orange and white
Black / black and white
Yellow/yellow and white/red/red and white.
couldn't compare with other axis, the 8 are wired in pairs on that.
any clues?
jim

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Re: What's setting free the magic smoke? Help please.
« Reply #3 on: May 14, 2014, 05:11:35 PM »
You would need to Ohm it as all continuity will tell you is that there is a connection. It could be a dead short and you would get continuity.
Hood
Re: What's setting free the magic smoke? Help please.
« Reply #4 on: May 14, 2014, 05:43:19 PM »
Ok. :)
Y to Y/W =1ohm
Y to R =1
Y to R/W =1
Y to O/W = 1
B to B/W =1.3
R to R/W = 1.3
O to OW = 1.3

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Re: What's setting free the magic smoke? Help please.
« Reply #5 on: May 14, 2014, 06:40:31 PM »
Its been a long time since I looked at steppers but an 8 wire motor should have 4 separate coils I would think.

If the above readings are with the wires separate then I would say you have shorts, if you still have the wires connected (parallel or series) then you need to separate and test between coils and also you can test between one coil and another to make sure there is no continuity.
Hood
Re: What's setting free the magic smoke? Help please.
« Reply #6 on: May 14, 2014, 06:59:14 PM »
They are all separate, so is is significant that there is continuity between the colour pairs, ie red/red and white, but then there is continuity between two of theses pairs...
thanks for the help by the way.
jim
Re: What's setting free the magic smoke? Help please.
« Reply #7 on: May 15, 2014, 01:13:29 AM »
Looking at the Gecko guide to steppers, there is no layout that can give continuity over 2 pairs in an 8 wire setup, so it looks like the stepper is junk.
Can I just swap it for new, replace the Gecko's and I am good to go, or is there something else I should check? Very nervous about the magic smoke.
jim

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Re: What's setting free the magic smoke? Help please.
« Reply #8 on: May 15, 2014, 03:02:21 AM »
There should not be continuity between coils as they should be separate, so as said above I think your motor is fried.
It is most likely a new motor and drive will be all that you need to get but do check all connections and the voltage of your PSU before you hook things up.
Hood
Re: What's setting free the magic smoke? Help please.
« Reply #9 on: May 15, 2014, 03:21:47 AM »
Will do, thanks again.
jim