G202 quits after 5-10 minutes

[wes]

I've gotta give Mariss kudos first. He has tried to help.

I have 4 G202's on a 3 axis machine. 2 of them run the X axis.

Machine specs:

Mach 3
PMDX 131 breakout board. www.pmdx.com
PMDX 135 power prep board
Avel Lindberg 800va torroidal transformer, 56vdc
homeshopcnc's rs34-960 960oz steppers: www.homeshopcnc.com
rated 7A per phase parallel.
All of this configured and assembled by Holt Control Systems.
The second x axis is wired to run directly off of the i/o from the first x axis. It's not configured as a slave drive in Mach. Although I have done this to no avail. Same issue.

I had problems with this drive earlier and sent it back to Gecko for testing. In the lag time, the owner of Holt Control Systems lent me his G202 drive. I used his drive for several months until he finally asked for it back last week. Mariss tested and said that the drive that I sent to him worked but when I plugged it back in today it quits just like before!

I ran out to Radio Shack today and got some 47ohm resisters to knock the voltage down. This was before I realized that Holt Control Systems had configured my steppers in parallel (7A) which is correct according to the specs on their site.

Anybody out there have any idea why this drive would quit but the loaner didn't? I had the loaner for 6 months without trouble. Any answers would be greatly appreciated.

BTW, There are NO loose wires in this control box. All ends are finished with mechanical connectors and screwed into it's matching block.

[CoAMarcus]

wes,

Have you swapped out the G202 for a known good one? If you do that and the problem stays with the axis, then the drive is fine. If the problem follows the drive, then it needs to come back.

Do you have a current set resistor? If so, what is the size of it?

-Marcus Freimanis

[wes]

Marcus,

Is Mariss your dad?

I talked with your dad? earlier today on the phone. I did have a known good drive in my cnc machine for about 6 months until the owner asked for it back. That's when I put this (bad) drive back into my machine.

You checked this drive last year and found it to be good but it has crapped out on me twice today during jobs.

I tried putting 47 ohm resistors on the x drives and they simply wouldn't even turn after that. I took the resistors off needless to say.

I have a really, really large magnifying glass with a built in circular light that I have been using to look for stray wires. I cannot find any. Maybe I can beg the drive that was in my machine for the last 6 months back from the owner. LOL.

I am back to where I was last year and am at my whit's end.

I am running tests and can only get it to quit when I am actually cutting wood and not air.

[wes]

I guess that I'll do like the guy with the 203v's that are randomly faulting and get some 6 amp resistors and try that.

[CoAMarcus]

wes,

Yes, Mariss is my dad. The names get pretty confusing, especially around here. ;-)

Anyway, you say that your machine only stalls when it is cutting wood, but it does just fine when it is cutting air. That sounds like you are running it too fast, and the torque required from cutting the wood is causing the motors to stall. Try slowing the machine down a bit, and see what happens.

A stalled motor has been asked to do too much, and it will continue to make noise after the stall. A drive shutdown, typically caused by a short circuit, will make the drive go silent and let the motor freewheel. Is your motor stalling, or is your drive shutting down? A stall is strictly mechanical, and it is cured by asking less of your motor and slowing it down. A shutdown is electrical, and the drive must come back here.

-Marcus Freimanis

[wes]

Thanks for replying Marcus,

The drive shuts down and the motor freewheels. My machine is pretty tight and I can almost cut with one side running, but not quite. The control box on this machine is immaculate. The guy that made this owns a company that makes nothing but control boxes, mostly for power plants, pumps etc.... $80K boxes so I think he knows his stuff. Holt control systems in Baton Rouge, LA.

He also plays with CNC and that's how I got to know him.

I've read some posts about these drives shutting down randomly on other forums. Shopbot had an interesting one that said that the Geckos are known to be flaky and that you should have a couple of spares on hand just because.

A couple of spares for me is a semester's worth of school clothes for one of my 4 children. I can't afford to buy extra parts "just because." I will keep trying but know that this drive will continue to fail here even if it tests good at your facility in California. (they also said that on the shopbot forum so I don't feel like the Lone Ranger here.)

I bought 500 resistors from Radio Shack today. I will be jumping a 270k across the 11 and 12 pins on the x axis drives and I'll cross my fingers and see what
happens next.

BTW, I put the wrong resistors on last night. I put on 47ohm and it needed 47K ohm. Oops. Throttled way too far back!

[CoAMarcus]

wes,

Let's be fair here; I cannot diagnose a drive you say malfunctions when you refuse to send it back for evaluation. This time we need it back here before we can send another one.

I looked up the records and I see we are out 2 free G202 drives, one we sent you UPS ground 10/01/07, the other via UPS overnight the following day, 10/02/07 when you called to ask where the first replacement was. The agreement was you were to send back the one you were having a problem with. You said you sent it, we never received it and the several tracking numbers you provided 11/13/07 were bogus.

We lean over backwards to help people; I believe someone talked to you yesterday to get at the bottom of your problem. There was confusion about the current set resistor value, whether the motor was wired in series or parallel, the phase current rating of the motor and so on. They suggested you send the drive back for evaluation if you had any qualms about it at all. It would cost you nothing, even return shipping is free.

If there is any finger-crossing while hooking up a drive, let alone putting a current set resistor in, then there is a problem. It is like crossing your fingers that the answer to "2+2" truly does equal 4; if you do the math correctly, or bother to at all, then you have nothing to worry about.

With the G202 that you have that does not work, we would be more than happy to see the actual drive. If you were to contact our shipping department, we would even be able to work it out so that all shipping is taken care of, on us. Once we have this drive in our hands, we can see what the problem is the same day we receive it. When we send a drive out that says "NPF" (No Problem Found), we mean it.

If you would like to take care of this matter, please email me personally at geckomarcus@geckodrive.com so I can send you everything necessary to get the drive back. We do try to please, and I will see to it that you get the red carpet treatment. ;-)

-Marcus Freimanis

[wes]

You are making me out to be a thief. I paid for those drives and sent them to back to you for testing one at a time. I have the original bill of sale from your company for 4 drives. I only have 4 drives and I paid for 4 drives.

If I had an extra one then I wouldn't be complaining about one quitting. I would simply replace it with the extra one, but I DON'T HAVE AN EXTRA ONE!

I guess that I'll just bite the bullet and order a couple of spares so that I won't have a 40,000.00 kitchen waiting on a 120.00 part.

BTW, This is my 5th cnc machine. I've had 3 with steppers and 2 with servos and I've never had this problem before.
Take a look at my machine at www.doorbot.net

[ger21]

Wes, you said you have two driving one axis. Have you tried swapping the two drives, and see if it still happens?

[wes]

Thanks for the reply Ger21,

Yes, I have done everything that can be done to diagnose the problem. Here is what I have done:

Checked all wiring for tightness
checked the seating of the wago connectors
moved the drive to the auxillary position on the pmdx board. (problem moved with the drive!)
Swapped steppers.
Borrowed another drive from a friend (it worked!)
I will be putting on 270k resistors today although I shouldn't have to.

Can we post pictures on this thread? If so, I can post one of my control box. If not, maybe I will put one up on my website.

added a picture on my website of the controller box. take a look.

Regards,
Wes

[BR928]

Marcus,

I have dealt with Geckodrive many times over the past couple of years and had nothing but good experiences. I in fact encouraged Wes to use your product based on those experiences. But, your reply in post #7 is borderline smarta$$. To suggest he never returned your product based on your shipping records is ludicrous. Do you really place that much faith in your records when humans are involved?

The paragraph about the 'finger crossing' and '2+2' seemed somewhat insulting.

Not everyone is the electronics guru that you are. That is why you are able to sell these PnP devices to the common Joe to use.

So after you insult someone twice, then promise them the 'red carpet treatment', your offer seems disingenuous.

Stan Holt

[Mariss Freimanis]

You are correct. In retrospect it did cross the line of being impolite.

I do stand behind Marcus, he's human and the reply reflected his exasperation. The drive could have been sent, evaluated and returned in less time than the duration of this thread. We do place faith in our record-keeping because the situation was unusual which made it memorable. He went against policy and sent a replacement drive before we received the suspect drive. It was his call to make and his decision to extended that courtesy. The suspect drive never arrived as promised and the tracking numbers supplied dealt with unrelated items to unrelated addresses. Those are the facts.

Marcus puts his heart and soul into managing production, maintaining equipment and being the purchasing buyer for all components used in production. He also does the vast majority of support calls. To say he is invested in doing his personal best and having pride in the results of his work is an understatement.

I am the designer of the drives so I know them well. The G202 is rated at 7A and the short-circuit protection trip-point is set at 8A. An unusually low inductance motor driven with an unusually high power supply voltage can have the 20kHz peak currents approach 8A and cause the drive to enter protective shutdown. The drive shuts off and the motor freewheels.

Another cause is setting the current higher than the motor's rated current. The iron in the motor enters magnetic saturation which causes inductance to plummet, inductive current to skyrocket to 8A and the drive shuts the show down again. I recall from my phone conversation there was some confusion about the motor specifics on that point. I wanted to see that drive to check its short-circuit threshold but I haven't been given the opportunity yet.

In any case, rudeness was not intended and I apologize for that given impression. What showed in the reply was simple exasperation.

Mariss