Smoke and fire...yes FIRE!

[fatal-exception]

I have no idea why, but when testing a G320 last night, all was going well, then after a small speed increase in the motor tuning (from 300 to 400) I moved the axis about 2 inches and the gecko let out it's magic smoke then actually caught on fire! It only burned for a few seconds, so nothing else was damaged, but still it was enough to shake me up for an hour.

What size of fuse should be on the motor supply line? It didn't trip the 20 amp that is inline.

I'm not pointing blame at anyone but myself. I'm sure I was doing something wrong.

Anyone else have this happen?

Paul

Also Mariss, I have a 203 that needs repair. How do we get this rolling? Can you fix the burnt 320? (I suspect not)

[CoAMarcus]

Paul,

What is your power supply voltage and current going to the drive? It could be that a MOSFET developed a short due to over voltage, and produced a tremendous amount of power for the little drive to take. Also, is the fuse a slow blow fuse?

-Marcus Freimanis

Edit: Send the G203V back to us, and we will evaluate it. If it is fixable, we will fix it and send it back to you free of charge. If it is not, we will dispose of the little gecko body for you. Please include a note describing what happened, and include a return address and contact information.

[fatal-exception]

72VDC, 20amps.

The fuses that I'm using are regular automotive type, so I don't think they are slow blow. Correct me if I'm wrong.
Paul

[CoAMarcus]

Those fuses are fairly slow-blow. The only thing I can attribute it to is an over voltage, damaging a MOSFET and creating a short across there. With it being a low-quality short, it had fairly high resistance. Even at low current, it will generate quite a bit of power, enough to blow up the drive and even start a nice camp fire like you did.

Do you have any pictures? I am very curious to see it. We have gotten some pretty toasted drives here before, and I have a sort of morbid fascination with charred printed circuit boards. ;-)

[epineh]

Originally Posted by CoAMarcus we will dispose of the little gecko body for you.

Heh, I have visions of a burial at sea with a bugle playing, or I guess it may be more fitting to have a burial at a machine shop...sorry, it's been a long day in the sun

Russell.

[CoAMarcus]

Well, we use the term "burial" kind of loosely. I suppose it would be more of a mass grave.

[fatal-exception]

haha, that's funny. Looks like the boxes of blown up product to my work place, except we deal with low current wireless devices, so it we get one back that charred, we get somewhat excited. (why do smoke and flame get techies excited?)

What type of fuse should I use? The round glass ones?

Paul

[CoAMarcus]

It is funny that you would ask about fuses, because I was just reading a post about them on our Yahoo group. Do NOT use automotive fuses or the glass cylinder fuses. The automotive ones are meant for 30V only most of the time, and when run at 80, if blown they will arc until the hole in the board is big enough to stop the arcing. The round glass ones are meant for AC only (for the most part), and it is best to use the bigger sand filled ceramic fuses.

The above explanation for the automotive fuses was something I had not thought about, but it would make sense for them to arc at 80V.

In regards to the flames getting techies all excited, I would attribute that to a more primal fascination with anything dangerous. Hence every little boys' extreme love of explosives. Now just imagine throwing a firecracker in the can of a G201...

[microcarl]

Over the past 5 years I've installed about 30, or so Gecko G210 drives in an industrial setting. These drives are powered by a 60VDC DC voltage source, driving size 34 stepper motors. The motors are mounted on a tussle that moves back and forth about 3 feet total. The cable is suspended overhead and is flexible enough to move with the trussell.

We've had about 3 Gecko drives burst into flames over that 5 year period. My findings are the following.

I suspect the problem all starts with a short developing within the cable due to 24/7 flexing as a result of the trussell movement. Well, the 3 Ampere fuse blows. Now the technician reads 7 Amperes maximum on the drive cover and sticks a Ampere fuse in place of the 3 Ampere fuse required to safely power the motor. The next time the cable shorts out, the 10 Ampere fuse can no longer protect the drive and, the smoke and flames clear the production area.

I've never complained about this as, I figure that it was the stupid technician who misdiagnosed the root cause of the problem.

To boot, I have a Sherline 2000 table-top mill that is using 3 G210 driven, operating at the minimum 24VDC supply. These drives are each powering an Automation Direct SureStep 270"/Oz stepper motor. The whole system has been operating flawlessly for nearly 2 years.

I just don't think a Gecko Drive can be beat for small positioning applications.

Now, I was wondering, how can I get another one or two of those pretty Blue Gecko Key chains? that came with my 340 servo motor drive.

[fatal-exception]

Yep, I suppose there's other drivers out there, but when you find one that works...all the time without fail, you stick with it. The keychains or the magnets are a nice bonus. Haven't got either lately Oh well, I still stick with these drivers, even if the odd one bursts into flames!

Take care all.

Paul

[neilw20]

A loose or badly crimped connector to a stepper can cause high voltage spike to kill the stepper driver, then the shorted driver cooks the motor.
Unplugging drives live is a no-no, and loose conectors are a hidden version.
Use GOOD QUALITY plugs, hopefully with crimped, not soldered wires.
Mechanically support wires near terminations.
Use the expensive fuses. Mightn't save the driver, but helps decrease the smoke at higher voltages. Low current arcs less than even 2A can be spectacular.

[fatal-exception]

I better take back the comment about freebies...I got a nice geckodrive sticker that will soon be plastered on my computer cabinet.

Paul