[johnm99]

Need help!!!

I am building a router based off the designs of JGRO - Mine will be modified to 4' x 4'. On first thought I was going with the xylotex board before I was told that would be pushing the limits...

So now I am back to the drawing board... The geckos were kicked out b/c cost, initially, but is there something else out there that is comparitive to the gecko. Something that will offer the power that is needed... for bipolar steppers... and not break the bank....

I am almost to the feeling that I am going to have to scale down my first machine... (can you help a guy for thinking big!!!)

[Mac T. Knife]

What do you have in mind for motors??

[johnm99]

What do you have in mind for motors??

I had in mind 276 oz/in bipolar motors from Automation direct....

I do not need the machine to move extremely fast... just get the job done in less than a day or two!

got any suggestions...!

[CJL5585]

Look on e-bay for some drives by the name of OMC or CENTENT.

They are Older Gecko drives sold under another name. I know a guy who has several sets of them.

These drives seem to last forever. You can pick them up for about $150.00 for a set of 3. They will handle up to 7 amps motor current which would allow you to use almost any bi-polar motor up to 600 -800 inch/oz torque.

Hope this helps.
Jerry

[ger21]

A lot of people do use the Xylotex with those motors. But, you'd probably get twice the speed using Geckos.

[johnm99]

Thanks

---- for all the comments...

i just do not want to throw away... any more money than I have too...

[ger21]

There really is nothing comparable to Geckos, btw as far as for amp and current ratings.

[CJL5585]

Johnm99:

Here are 3 Centent (old Gecko drives) with 3 Powermax steppers on e-bay. This is the guy I mentioned.

http://cgi.ebay.com/3-Centent-CN0143...QQcmdZViewItem

Jerry

[CerveloRod]

Why not start with the Xylotex? They resell for just about what you pay for them.

I am using the same setup, 276oz/in from AD, Xylotex 4 axis, 24 volts, 2.6 amps. Works pretty good with my mini-mill.

I am sure I would get better performance from Gecko's but I also started at half the cost.

Downside to Xylotex, if you blow an axis, and don't do chip replacement, the whole board has to go back. I ended up buying a second one, that will get resold eventually. With Gecko, you could buy just one extra to replace that axis.

Rod

[johnm99]

I just looked at those... I also checked the centent website... are they still an active company... or have they just evolved into GECKO

[CJL5585]

Gecko manufacturers drives for other companies who want to have a drive with their own namebrand on it.

Gecko also makes the drives sold under the US Digital Name.

These Centent drives are a larger size version of the Gecko 210. I have built several systems around them.

Jerry

[johnm99]

Why not start with the Xylotex? They resell for just about what you pay for them.

I am using the same setup, 276oz/in from AD, Xylotex 4 axis, 24 volts, 2.6 amps. Works pretty good with my mini-mill.

I am sure I would get better performance from Gecko's but I also started at half the cost.

Downside to Xylotex, if you blow an axis, and don't do chip replacement, the whole board has to go back. I ended up buying a second one, that will get resold eventually. With Gecko, you could buy just one extra to replace that axis.

Rod

what would cause me to blow an axis... is there any way to prevent this from happening... cooling the board?....using less power??... running the motors slow...

This is definately not my area of expertise so anyt advice here would be appreciated... (neither is spelling)

[CerveloRod]

Disconnecting wires while active is the MAIN cause. I think it has to do with back-EMF, but I'm not an expert. I blew one because of a main circuit breaker problem, so I then re-wired my garage to provide a seperate circuit for the mill, and the PC, and my lathe. Now I have no problems with power.

I would believe you could also blow the driver by using a vRef higher that you should, but you set that first thing out of the box and I have only changed it once.

One more note, in your driver box make sure to have provisions for airflow in and out. I had 2 small fans in, and just vents out, and when it got 95 degrees here out west I started losing steps on Z. I added another fan blowing out and it solved that problem.

Rod

[johnm99]

Disconnecting wires while active is the MAIN cause. I think it has to do with back-EMF, but I'm not an expert. I blew one because of a main circuit breaker problem, so I then re-wired my garage to provide a seperate circuit for the mill, and the PC, and my lathe. Now I have no problems with power.

I would believe you could also blow the driver by using a vRef higher that you should, but you set that first thing out of the box and I have only changed it once.

One more note, in your driver box make sure to have provisions for airflow in and out. I had 2 small fans in, and just vents out, and when it got 95 degrees here out west I started losing steps on Z. I added another fan blowing out and it solved that problem.

Rod

While active in the main??? what do you mean?
kinda sounds like my first computer experiment the thing was running when i pulled the cables out... that did not go over well...

I would think my shop is setup pretty good on the electrical.. the guy I bought it from was a dedicated woodworker...

what is vRef?

i wonder why you lose steps when it gets hot... ? I will take that into considerations when i put my box together... I was going to use an old pc box... i build puters in my spare time....

[ger21]

Almost all blown drives are caused by either miswiring, or disconnecting motors while power is applied. Wiring a motor incorrectly will instantly kill a drive. I don't see any reason to keep a spare on hand, unless you're using it in a production environment. Xylotex will repair blown drives for a small fee and are pretty quick on turnaraound, from what I've heard.

[ger21]

i wonder why you lose steps when it gets hot... ? I will take that into considerations when i put my box together... I was going to use an old pc box... i build puters in my spare time....

The Xylotex must have a fan blowing on the heatsinks. If it gets to hot, it will cause missed steps and rough running.

The vref is a small pot that adjusts the current the drives supply to the motors.

[CerveloRod]

rephrased; the number one cause of blowing the driver is wiring issues. If a wire comes lose while it is moving it sends to much current back into the chip and POOF....

I have my whole control box in a ATX case. MPJA 28 volt power supply, xylotex driver, fans, PC, etc. I have a picture somewhere I'll post in my gallery, http://www.cnczone.com/gallery/showg...r/6377/cat/500.

Go to Xylotex.com and read the setup sheet for the explanation of setting vRef.

Rod

[pminmo]

Running the 3977's (chips on the xylotex) at 2.8 Amps (automation direct 276ozin) is a definite push. While I wouldn't recommend it, if I were going to do it, i'd run no more than a 30vdc power supply. The 3977's are used on two of the drivers on my website.

[ger21]

Running the 3977's (chips on the xylotex) at 2.8 Amps (automation direct 276ozin) is a definite push. While I wouldn't recommend it, if I were going to do it, i'd run no more than a 30vdc power supply. The 3977's are used on two of the drivers on my website.

You should run those motors at 2.5A. Any more and you risk losing your Xylotex.

[johnm99]

well i was thinking the 2.5A would be the limit... and the way i understand it my motors will be limited by this.

I would rather limit my motors than blow my board... if all else fails... I can scratch the design I am using and go to something smaller...

I have already been offered a lathe for my finished router!