2 axis Gecko 251 setup help?

[fretsman]

I actually have a taig lathe fitted with a generic stepper system setup (image below) but ithe drives are whining (chopper drives?) so I'd like to be able to setup a decent set of quiet motors, drivers breakout board and power supply for it.

I'd like to use the Gecko 251's as I've been hearing some good things about them but I'm not sure which BOB, motors and power supply would be a good match for them. I'd like to use a set of steppers that have around 156 oz. and be a NEMA 23 mount. I was thinking of these running in bipolar parallel (best performance, yes?):

KL23H251-24-8B Price: $29.95 ( in stock)Rated Current: 3.4A, Rated Voltage: 3.1V (in Bipolar Parallel)

http://www.kelinginc.net/KL23H51-24-8B.pdf

For the BOB, I hear good things and bad things about the C10 because it's not opto isolated, it's buffered and I have no idea what that means.

Power supply, I'm thinking that will come last after I figure what motors I'm using, correct?

I know you guys get a million of these requests but I don't see any for smaller setups like I'm after.

Any help would be appreciated -

Thanks so much,
Dave

[Crevice Reamer]

Hi Dave!

By the time you buy 2 G251s and a BOB and probably a 5V power supply for the BoB, you are only saving about $60 under the cost of a G540. Yeah, I know the G540 has 4 drives and you only need 2--Think of it as 2 drives and 2 spares for not much more than the price of 2 g251s.

You also get the wiring convenience of the built in BoB plus all of the unkillable features and the 10 Microstep to full step morphing.

That's a lot of bang for $60. I think you should go with the G540.

That 156 oz motor seems a little weak to me for the 20 TPI lead screw. Maybe for ball screws, or a Sherline, it might be ok.

I would go with at LEAST the 270 ouncers, and they're already wired internally for Bipolar Parallel, so only 4 wires to connect.

http://kelinginc.net/KL23H276-28-4B.pdf

You could also go a bit bigger and use 387s

http://kelinginc.net/KL23H284-35-4B.pdf

either of these will work very efficiently with the small drives, and they both are 4 wire Bipolar Parallel motors.

As to power supply, it's a no-brainer. The $50 Keling KL-300-48 48V/5A will be more than powerful enough for even 2 387s.

CR.

[fretsman]

Thanks for the info, CR, an I must admit, you're actually bringing me over to considering the 540 as I was thinking about adding a motor to a screw-modified tailstock which could be pretty handy.

Quick question, how do you go about connecting the resistor to each drive outlet? I see it has a little schematic showing the resistor locations but I'm not sure I understand how this is wired in?

Got a pic of your setup?

Thanks again and if anyone else has some thoughts and ideas, I'd love to hear them-

Dave

[Crevice Reamer]

The G540 comes with 4 DB9 connectors. (Another cost saving benefit) When you solder the motor wires into the connector, you also solder the 1/4 Watt resistor therein.

A good source of the 2.7K and 3.48K resistors is http://digikey.com/

CR.

[fretsman]

Just wanted to update as I finally got my CNC Taig Lathe wired up with the help of Crevice Reamer (thank you sir - ).


Like a bonehead, I completely forgot to wire in my fuseholder which I will have to do shortly-

A couple of pics for you of the front of the controller sporting the logo I drew up which I thought was rather appropriate. and also a quick shot of the back as well.

[Crevice Reamer]

Very NICE! Excellent work! Good Job! Which motors did you go with?

LOVE the logo.

CR.

[fretsman]

Thanks, I ended up going with the 270's and I believe they'll be perfect -

Dave

[haciman]

Hi.

I ask question about connect the G251s.

I have 1 piece G251s and 2 piece ims im805 microstepper drive.My motors 1.85Nm 3.2V 2.8A bipolar stepper motor (4 lead). My power supply 42V DC(unregulated).



This drivers and motors connected for test. All drivers (G251s and im805) adjusted 2.7A current.

I used trial version Mach3 for test. My motors diffrent velocity worked at the test (test time 10 minute). Only a stepper motor (at the connected G251s) warmed (approximate 30C degree). Other motors (connected the im805) not warmed.

Why this motor warm?

[fretsman]

You may want to start your own thread so that the folks at Gecko will see it much easier -

Dave

[haciman]

Originally Posted by fretsman You may want to start your own thread so that the folks at Gecko will see it much easier - Dave

Ok.

[Mariss Freimanis]

fretsman,

Put a 100 Ohm resistor from SIGNAL GND (term 12) to your BOB for each drive. That will stop the whining.

Mariss

[fretsman]

Thanks, Mariss but you're a couple of months too late as I now have bought the G540 as pictured above.

Great product you folks make and I sincerely thank you for that-

Dave