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Author Topic: one pop then another, no Gecko light  (Read 7628 times)

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Offline Hood

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Re: one pop then another, no Gecko light
« Reply #10 on: September 10, 2013, 05:46:37 PM »
Sorry dont know enough about stepper to say :(
Hood

Offline RICH

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Re: one pop then another, no Gecko light
« Reply #11 on: September 11, 2013, 06:37:31 AM »
Jim,

Quote
So, would a tight machine stalling a motor cause this fuse to pop?
The G201's are limited to 7 amps, the drive amp setting is determnined by the size of the resistor on  the drive connections.
I use a switch array which allows selection of different drive resistor values such that different stepper motors can be used. 

I use quick blow fuses to limit the amperage available to the drive and they are not above the rating of the drive.

Let me also add that you should have a cap on each the the axis  connections for the G201's. The newer drives have the cap built in.
So read your drive instructions.

The info on Gecko site is a simple test for testing the drive and if it dosen't pass the test then the drive is blown and not repairable.

In general, when a motor is stalled the current goes to infinity and would burn it up as all the energy is going to heat.
So when a stepper stalls max available current is  delivered, in your case 10 amps +- ........... depends on the fuse on when it will actual blow.

You provide a desired voltage and protect / limit the available current to the drive  to protect motor. READ THE MANUAL!

Blow a drive and you are forgiven. Blow another drive and you deserve to pay the price! ;)

RICH

 

 
Re: one pop then another, no Gecko light
« Reply #12 on: September 11, 2013, 10:17:20 AM »
In general, when a motor is stalled the current goes to infinity and would burn it up as all the energy is going to heat.
So when a stepper stalls max available current is  delivered, in your case 10 amps +- ........... depends on the fuse on when it will actual blow.

That is not true at all.  If the motor stalls, current will, eventually, reach the maximum value allowed by the current limit resistors on the Gecko.  The Gecko will never allow the current to exceed this value, unless the Gecko is a;ready damaged and no longer working correctly.  Even in that case, the current NEVER "goes to inifinity'".  The motor windings have resistance, which also limits the maximum current the motor can draw.  You can lock the rotor on the motor for as long as you like, and there will be no damage whatsoever to the motor or the Gecko. The fuses only protect the motor, and wiring, from over-heating in the case of a Gecko failure, a wiring short, or other failure.

Regards,
Ray L.
Regards,
Ray L.

Offline RICH

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Re: one pop then another, no Gecko light
« Reply #13 on: September 11, 2013, 01:03:51 PM »
Ray,
Thanks for the clarifications. I'll try better wording next time.  ;)
RICH
Re: one pop then another, no Gecko light
« Reply #14 on: September 11, 2013, 03:37:59 PM »
Well, thanks for the input guys, I did find three hidden 10 amp fuses, two blown, and one by one replaced them. Now I have three lights on the three Geckos.
jogging on two axes, great. jogging on the third, the x, grumbling movement, even with nothing on the motor. Swapping the Gecko's, and the problem goes with it.
So there is a fault on the Gecko 201, and maybe the stiff axis stressed it to failure.
I have never looked at the manual till recently Rich, the Gecko's were on the machine when I got it, and apart from a similar incident in 2007, no problems.
Jim

Offline RICH

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Re: one pop then another, no Gecko light
« Reply #15 on: September 12, 2013, 06:08:49 AM »
Jim,
What is the amp setting on the drive for the X axis?
Is the X motor the same as the other two?
Can you better describe other than "grumbling?

RICH
Re: one pop then another, no Gecko light
« Reply #16 on: September 12, 2013, 07:13:39 AM »
Well Rich thanks for the interest,
all three steppers are the same, and it's all been running well for a few years now.
The grumbling noise, well the others wizz along nice constant high pitched wheeeee. The one with the faulty driver, that's what I am assuming, as the problem moves with it, goes err. errerr eererr. wheeee errerr. errerrerr wheeee err. err. err. Random roughness, stuttering, stopping and starting very quickly... swap the driver and wheeeeeee.
The drives were nicely heatsunk, and only ever got tepid to the touch, if that's any use.
Amp setting for the drive? don't know.  :-[ Where would I find that?
Jim
Re: one pop then another, no Gecko light
« Reply #17 on: September 12, 2013, 07:20:05 AM »
Quote
The grumbling noise, well the others wizz along nice constant high pitched wheeeee. The one with the faulty driver, that's what I am assuming, as the problem moves with it, goes err. errerr eererr. wheeee errerr. errerrerr wheeee err. err. err. Random roughness, stuttering, stopping and starting very quickly... swap the driver and wheeeeeee.
Tempted to suggest one axis may need cleaning, and one phase in the driver has been cooked. Simplest test is to drop a new driver in; even cheaper is to swap one of the other drivers in temporarily.

The X axis can often pick up dirt which then clags the balls in the ball nut. Cleaning all that out is an exercise for a masochist, but it can be done. (Been there, done that.)

Cheers
Re: one pop then another, no Gecko light
« Reply #18 on: September 12, 2013, 07:47:20 AM »
Hi rcaffin, yes, I have swapped the drive and the problem migrated with it. Interestingly whoever made the machine seemed to want it to work as if by magic, all the threads are hidden inside aluminium box section, but at the time there was some build up on a rail on the x.
New Gecko is on it's way at the moment, fingers crossed. Thanks for the interesst.
Jim

Offline RICH

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Re: one pop then another, no Gecko light
« Reply #19 on: September 12, 2013, 08:09:12 PM »
The G201 amp setting is accomplished by placing a  resistor across two terminals of the drive.
READ THE MANUAL since it shows how to calculate the resistor size. Obviously you have not installed the capactor on the
drive as I noted before.

RICH