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Author Topic: Overheating motors  (Read 3270 times)

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Offline ernie

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Overheating motors
« on: August 08, 2008, 05:26:34 PM »
Hi.  We use desktop 4-axis mills for jewelry.  Gecko based controllers with G201 drivers, Mach3 software.  After a year, on 2 mills the motors have gotten so hot that the cables come into the motors got burned (smoke came out of the cables).  The machines were in 2 different locations. 

Could it be that the drivers are sending too much current to the motors?
 or the coils on the motors went bad and got too hot?

I'd appreciate your comments.

Thanks

Ernie   :)

Offline Hood

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Re: Overheating motors
« Reply #1 on: August 08, 2008, 05:28:26 PM »
Possible that your current limiting resistors went bad/loose, that would put full current through to the motors.
Hood

Offline ernie

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Re: Overheating motors
« Reply #2 on: August 08, 2008, 06:37:55 PM »
Thanks.   

Can Mach3 control the amount of current that goes to the motors?

Offline Hood

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Re: Overheating motors
« Reply #3 on: August 08, 2008, 06:41:17 PM »
No, the drives supply the current, the last two terminals in the block is where you are meant to have a resistor depending on the size of your motors. If there is no resisitor the Geckos put out 8amps to the motors, that would make the motors very hot if they were for instance 2 amp motors.
Hood

Offline ernie

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Re: Overheating motors
« Reply #4 on: August 08, 2008, 07:47:11 PM »
sorry for my ignorance, but the resistors are built-in the Grecko 201 drivers or they have to be  connected to the driver's output.

Offline Hood

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Re: Overheating motors
« Reply #5 on: August 08, 2008, 07:50:35 PM »
they have to be connected, will post a pic in a min
Hood

Offline Hood

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Re: Overheating motors
« Reply #6 on: August 08, 2008, 07:55:35 PM »
The pic is from the manual, I have put in red where the resisteor connects and the blue is circling the resistors needed for different current settings.
Hood

Offline ernie

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Re: Overheating motors
« Reply #7 on: August 08, 2008, 08:09:41 PM »
I see

I guess, probably the quality of the resistors installed was not good.

Thanks a lot

Ernie

Offline RICH

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Re: Overheating motors
« Reply #8 on: August 09, 2008, 07:20:41 AM »
Ernie,
Suggest you get in touch with Geco, try to talk to Mariss , and ask him how to test the drives. You just take a few
Ohm measurements and you will know if you blew your drives. I don't remember the sequence anymore. Steppers have an insulation rating ?? 90 C ?? and if you exceed it then they may be shorted. You can test the steppers by measuring winding resistance of the phases. ( of course with power off! ) I would be leary of re-using a "smoked" motor!
Geco may allow you a one time replacement of a single drive " tell them your willing to make a true confession-thats where
you inform them how you blew the drive in writing", hey, a few moments on a note pad may get you one drive at no cost.
May I suggest you review your power supply ie; that each drive is fused and additionaly that you have that cap on the drives and the resistor values are correct per Geco instructions.
Sad for your losses but lets not duplicate again.

RICH