X2 conversion electronics advice?

[Farasien]

Hey all-

I've been working on getting the mechanicals on my X2 done, and I'm within spitting distance of most of it. Now for step #2... Electronics.

I am planning on building a Gecko 590 system, based on the cost effectiveness and stellar quality of their stuff- that's the part I do know. What I don't know is the rest of it. I checked out Kelling CNC's offerings for motors and power supplies, and from what I can glean from the G590 user's manual, I have a few choices to make. I figure for motors, I'll go with the NEMA 23 495 oz/in KL23H2100-4BM. I know its probably a lot more muscle than is really needed for the X2, but I would like to not see stalling if I want to cut the occasional stainless part. For power supply, I'm really confused... I figure the 3 choices I have for max power to the motors is, again from Kelling, the KL600-48 (48V, 12A for $140), the KL300-48 (48V, 5A for $50) or the KL350-48 (48V, 7.3A for $60). What I don't understand is weather the amperage out of the power supply matters or not. I have an enclosure for all the gear once its in house, but I was wondering weather or not a case fan (or series of them) would be beneficial. If so, does anyone have suggestions on how to hook these into the final system?

Does anyone have any suggestions? I've heard some poeple use smaller oz/in motors for the X and Y axes... outside price, is there an advantage to doing that? I'm not looking to make this into a production machine, so while I'd like to have a decent amount of speed, its NBD if its a bit sluggish. Secondly, which of the 3 power supplies would be best for the conversion? The price for me isn't so much of an issue really, I just want to make certain not to burn things out due to my inexperience at this. Does anyone have any suggestions for other distributors for other (and/or better) options for the components?

Thanks-

-Farasien

[Rustybolt]

I have the same basic setup as you are considering. I'm using gecko 201s and the same keling motors on the x and y. As far as motor power is concerned, I'd rather have it and not need it than the other way around. My z axis is a 300 oz/in size 34 motor simply because I already had it. It has no trouble moving the spindle up and down. I built my own power supply using maris' directions at the Gecko webpage. Mine is 36v at 10 amps and is probably overkill for current. 48v and 7.5 amps is probably the better power supply. I'm sure there are more knowlwgeable people here to straighten you out on that. 36/10 works for me. I am also using a Cambell Designs breakout board. I like it for the limit and homing switch options it gives. IMO it makes wiring the whole thing up more foolproof.
One thing you should consider when you wire everything up. I installed fast blow fuses on every line(hot) wire in the circuit. Fuses rated just a little above the amperage for that circuit. This is to insure that any problems aren't daisychained down the line into other expensive pieces of equipment.
The mechanical part was easy for me, being a machinist by trade. The electronics look daunting , but if you take it slow and plan things out it really isn't all that difficult. I had a while where i was having a difficult time getting the motors to do what they were supposed to do. Turned out I just had two motor wires reversed. Hey. I did it, it can't be that difficult, right?
Good luck.
Keep asking questions.

[TOTALLYRC]

Hey all-

I've been working on getting the mechanicals on my X2 done, and I'm within spitting distance of most of it. Now for step #2... Electronics.

I am planning on building a Gecko 590 system, based on the cost effectiveness and stellar quality of their stuff- that's the part I do know. What I don't know is the rest of it. I checked out Kelling CNC's offerings for motors and power supplies, and from what I can glean from the G590 user's manual, I have a few choices to make. I figure for motors, I'll go with the NEMA 23 495 oz/in KL23H2100-4BM. I know its probably a lot more muscle than is really needed for the X2, but I would like to not see stalling if I want to cut the occasional stainless part. For power supply, I'm really confused... I figure the 3 choices I have for max power to the motors is, again from Kelling, the KL600-48 (48V, 12A for $140), the KL300-48 (48V, 5A for $50) or the KL350-48 (48V, 7.3A for $60). What I don't understand is weather the amperage out of the power supply matters or not. I have an enclosure for all the gear once its in house, but I was wondering weather or not a case fan (or series of them) would be beneficial. If so, does anyone have suggestions on how to hook these into the final system?

Does anyone have any suggestions? I've heard some poeple use smaller oz/in motors for the X and Y axes... outside price, is there an advantage to doing that? I'm not looking to make this into a production machine, so while I'd like to have a decent amount of speed, its NBD if its a bit sluggish. Secondly, which of the 3 power supplies would be best for the conversion? The price for me isn't so much of an issue really, I just want to make certain not to burn things out due to my inexperience at this. Does anyone have any suggestions for other distributors for other (and/or better) options for the components?

Thanks-

-Farasien

If you mean the G540 system then you are on the right track.

Total power supply is calculated by the total motor amps times .65
3.5/motor is the max the G540 can handle x 3motors x .65 = 6.8 amps.
The 7.3 amp should be more than enough unless you run the fourth axis with a 3.5 amp motor and use full power all the time. The sherline 4 axis which I have and a lot of us use is a 2 amp motor and should still work with the 7.3 amp ps. How often will you be doing 4 axis full power coordinated motion?

Those motors are 3 amps each and 7.3 amps will be plenty. Having extra amps doesn't hurt anything but not enough will cause all kinds of headaches.

I think many guys are going with a nema 34 on the Z but seach around and you will see what and why they are doing it.

With 48v on those motors you will get pretty good speed, but remember that the specs are holding torque and what we need is torque at a certain speed. You cant get much machining done if you are not moving. IMHO if you will do the occasional piece of stainless and will do mostly aluminum and a little steel or cast, get motors for what you need to due most of the time. If rustybolt gets good rapids on his machine and is happy with the power you will have faster rapids and more power because of the higher PS voltage that you will be using.

This is keling's G540 package and he specs the 382oz motors.

G540 4 axis package (1PCS G540 +4 pcs KL23H2100-30-4B (3/8” Dual
shaft with a flat) 382 oz-in + 1 pcs KL-350-48 48V/7.3A 110V/230V
power supply): $549.95

You could always call and ask why. I know he sent some motors to Gecko for evaluation for use with the G540 and that could be the reason.

Fan(s) in the encloser would probably be a good idea. 12v computer fans many of us have lying around or are cheap along with an old pc power supply. If you can find a 50v dc fan you could just run it offf the main power suppl, they don't take much power to run.
Search the zone for enclosure and there are some great ideas and photos.

After writing all of this, I did something amazing an read the G540 manual http://www.geckodrive.com/upload/G54...3%20MANUAL.pdf and low and behold it answers most of you questions right off the bat. Time for me to shut up. LOL LOL

[Farasien]

OK, so after talking with Kelling, I decided to go with their 387 oz/in motors and a 48V/12.5A power supply. According to them, if I went with the 495 oz/in motors, it would be slow as molassas and sledgehammer-tack nail level overkill for what I want to cut. So now, I have all the base stuff needed for the conversion. I think.

I'm looking into the fuses you suggested, Rustybolt. I like the idea of multi-layer protection, as I have this problem with entropy increasing in power everywhere I seem to go (Murphy's Law was written for me). I was considering going with fuses (even thought of maybe using automotive fuses), then it hit me.... Are there any circuit breakers out there in the very low amperage (3.3A or so) range? I would prefer to have a bunch of those for the build rather than fuses if I could help it. Also, wouldn't it be better to put in fuses for just below the rated amperage rather than over it? While I have full confidence in the Gecko g540's robustness, I'd rather not test its limits for the sake of curiosity. Does anyone know a place I could get either low amperage breakers I mentioned above or a small, simple fuse box to house all the fuses in the same place, preferably one that wouldn't take up the majority of my enclosure?

Does anyone know if there is a how-to or tutorial as to how to wire everything up? The manual that was posted (and a copy of which came with the controller) didn't really give alot of hands-on info... I'm not really expirenced with most electronics and the thought of frying my parts scares me a little. I've read little bits here and there where I can find info on the web (most of it on the Zone, naturally) but most of that seems tailored to veteren circuit slingers.

Another issue I was thinking about was stepper heating. I know this is expected of stepper motors, but I can;t help but wonder weather cooling them off wouldn't extend their lifespan a bit. Towards that end, I was considering ordering up some extruded heat sink-like aluminum stock and bending it to fit the contours of the motors. Would this be a waste of time? If not, would epoxying them directly to the motor housings work?

Lastly, is there any downside to putting the spindle control board and computer case fan power supply in the same enclosure? I want to have all the electronics in one place (minus the computer, of course) if possible to minimize wire routing nightmares. The only thing I see might cause an issue is isolation of the three, but I figure I can bend up a Faraday cage for one or all three out of some thin steel or aluminum if its needed.

-Farasien

[Crevice Reamer]

Hi Farasien. Congratulations on your purchase.

Fuses on the DC side are not a good idea.

You are using the unkillable G540. It has auto motor temp control--No heat sink needed.

Wiring a G540 is much simpler than anything else. Just run motor power + - to the 540. Run 5V power to 540. Fabricate motor cables and attach to motor on one end, (Stagger connections) and the provided connectors on the other end. Don't forget to buy and solder the 3.5K Current limit resistors in the DB9 plugs. 3.48K resistors are available from:

http://digikey.com/

You can use THIS wire for motor cables and home/limit switches. Ground the drain wire ONLY at the driver end.

http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

If you don't already HAVE them, these are excellent home switches:

http://cgi.ebay.com/6-CNC-LIMIT-SWIT...742.m153.l1262

They are NO, so only for home switches. the whole set of 6 switches costs less than ONE switch would cost at Radio Shack.

Limit switches usually need to be NC. They are normally wired in SERIES, so they only need 2 inputs.

Limit and home switches are connected to the input pins of the G540.

Make sure you use the latest wiring diagram for your revision number.

With the tiny size of the G540, I would be surprised if most people DIDN'T install it right in the computer case. Just don't share anything between them.

Don't forget that the G540 can also CNC control your spindle speed with only a few wiring connections.

CR.

[kawazuki]

CR - the rev 1 540's needed 5v+ and didn't do spindle VFD, the rev 3 540's don't need 5v - its internally generated and now do the spindle control!
And whats this 'auto motor temp control' ? there is no feed back from the motors to the controller - motors will get as hot they like given the restricted ampage being pushed through them! The 3.5A limit was only a nominal level to save on higher capacity components being needed on the boards - it is a 'budget' controller after all!
Sorry to thread jack

[Crevice Reamer]

And whats this 'auto motor temp control' ? there is no feed back from the motors to the controller - motors will get as hot they like given the restricted ampage being pushed through them!

You are right Kawazuki. I was referring to the auto idle current limiting for the DRIVE. I guess I had a brain spasm and called it auto MOTOR TEMP. It still does reduce the motor temp though, by reducing current to the motors while they are standing still. And anyway--Stepper motors are MADE to get hot. He will NOT need any kind of heat sink.

Maybe YOU know what revision G540 he has, but I don't. If he DOES have an earlier version though, he can return it for upgrade.

The 3.5A limit was only a nominal level to save on higher capacity components being needed on the boards - it is a 'budget' controller after all!
Sorry to thread jack

Yes, there IS a 3.5A limit, much above which will fry the drive--I'm not sure why you posted about it though. The G540 is a revolutionary product. For an "economy drive" it sure beats the heck out of anything else that operates within it's cost/parameter limits.

CR.

[Farasien]

Sorry I didn't specify this... I got the driver only about 3 weeks ago, so unless Mariss and crew released something within that time, its the most recent version.

-Farasien

[Mariss Freimanis]

Farasien,

Don't worry about the G540 too much. The design doesn't permit more than 3.5A to flow through the motors even if you have no current set resistor at all. We recommend you use a 3.5K resistor for 3.5A motors only because that permits the G540 to go to a 70% of rated current during standby. Because of a design quirk standby current is not reduced unless a 3.5K resistor is present. No harm results either way; it simply insures your motor is not sitting there dissipating a lot of heat while it's doing nothing standing still.

Mariss

[Farasien]

Thanks Marris and CR- I highly appreciate the help.

Got another question for you; As I said before, electronics isn't my strong point. So for the resistors... 3.5 kOhm resistors at what... 1/4 watt? More? Less? I have wires, q/d connectors and limit switches on their way (spindle control and limit switches will be the next step in the whole thing) but no idea what I specifically need for resistors. I looked around the shop and I have a few 3.3 kOhm @ 1/4 watt resistors readily available, but no 3.5's. Though Marris said I don't NEED them, I'd like to have them in order to keep a little less juice going through the motors while on they are on standby...

-Farasien

[Mariss Freimanis]

Use the 3.3K 1/4W resistors you have on hand. The current will be 94% of rated; it's unlikely you'll notice the difference. High-speed torque (the kind that matters) is unaffected by resistor size.

Mariss

[Farasien]

Hi all-

Spent the day soldering and wiring, but I have a question (again)... CR, you said to ground the drain wire at the driver end... What exactly did you mean by this (wiring is not my specialty by any stretch of the imagination)? I bought 4 wire shielded cable for the motor cables and soldered everything up according to the diagrams, but there is a bare wire included in the cable I bought. Did you mean I should hook the bare (ground?) or some other wire to the connector on one of the DB9 pins between the resistor soldered to pins #1 and 5? According to the literature I got from Marris's fine company, those are marked as ground...

Its gettin' there... I hope!

-F