[jjacstcy]

Anybody running 23's on a large machine? I am converting an old 5x10 machine for a friend that has 450oz 34's on it. The machine is belt driven with gears and the motor mount plates and made to accept either stepper. Problems that new 34's have a half inch shaft and the old 34's have a 3/8 shaft. I would like to use some 23's with a 3/8 shaft that are 380oz. Anyone see a problem with this? If I go with the 23's I will probably use a g540 to drive them.
Thanks

[ger21]

The only 3/8" shaft steppers I know of are the 570oz from Keling. They are Nema 23 bolt pattern, but slightly larger bodies (60mm). They are also 5 or 6 amps, so you 'd need G201's or G203's to run them.

[jjacstcy]

So you think the newer 23's are a suitable replacement for the 16-18 year old 34's?

[automationtechinc]

The only 3/8" shaft steppers I know of are the 570oz from Keling. They are Nema 23 bolt pattern, but slightly larger bodies (60mm). They are also 5 or 6 amps, so you 'd need G201's or G203's to run them.

This motor is NEMA23 and 3/8" shaft
NEMA23 570oz/in 5A 3/8

Check what is your power supply and stepper driver

Automation Technology Inc. | Stepper Motors, Servo Motors, CNC Stepper Motors, Stepper Drivers, CNC Kits, Stepper Kits Automation Technology Inc

[FannBlade]

This motor is NEMA23 and 3/8" shaft
NEMA23 570oz/in 5A 3/8

Check what is your power supply and stepper driver

Automation Technology Inc. | Stepper Motors, Servo Motors, CNC Stepper Motors, Stepper Drivers, CNC Kits, Stepper Kits Automation Technology Inc

"Off Topic"
Great look on the new site! Very easy to navigate. Thank You! Thank You! Thank You!

[jjacstcy]

This motor is NEMA23 and 3/8" shaft
NEMA23 570oz/in 5A 3/8

Check what is your power supply and stepper driver

Automation Technology Inc. | Stepper Motors, Servo Motors, CNC Stepper Motors, Stepper Drivers, CNC Kits, Stepper Kits Automation Technology Inc

I am changing everything out. Can you come up with a kit using the 23's with the 3/8 shaft?

[bel630]

i saw cncrouterpart selling 380oz nema23 with 3/4" shaft.. try to look at them..

[awerby]

This doesn't sound like a great idea. If they don't work any more, replace the 34-frame motors, with other 34 frame motors. 23-frame motors are fine for smaller machines, but yours is too big for them. I'm sure you can find suitable 34s with 3/8" shafts, or adapt to whatever you can find. And while the G540 is a really nice all-in-one controller it's also too small to drive this machine. I'd say bite the bullet, get a breakout board and some bigger-capacity Geckos.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[KOC62]

I don't get it. "If it ain't broke don't fix it".
So far it is just a shaft size problem. Why not get a coupler to go from one size to another, rather than change motors?

[Torchhead]

Torque is torque. the frame size of the motor is not always a predictor of the shaft torque of a the motor. Newer 23 frame motors have more torque (and lower rotor inertia) than older 34 frame motors. It was not too long ago that the average 34 frame motor was about 300 oz-in of torque. now you can get them up to 1280 oz-in or more. If your gantry weight (total) is less than 100 lbs and you have a belt reduction to the pinion of about 3:1 you can get upwards of 30IPS/sec acceleration with a 570 to 620 oz-in motors (dual drive on the gantry). For contact cutting where acceleration is no as important a more aggressive belt reduction is a torque multiplier.

TOMcaudle
www.candcnc.com

[jjacstcy]

Well after a lot of thought I am going to change everything out in this old machine and go with the following. Any thought before I purchase this stuff is appreciated.

PMDX 133 Motherboard
PMDX 126 BOB
PMDX 107
3 Gecko 201's
Nema 34's from Keling
KL34H280-55-4A

Any ideas on what size power supply that I will need? Will I need a 12v or 5v wall wart to hook any of this stuff up?

[awerby]

Those Gecko 201 drives can handle 80 volts (a lot more than the G-540 at 50v max). You'd be seriously shortchanging your machine if you tried to run it off a 12v wall wart. I'd suggest using a power supply only slightly less than 80v, maybe 77v or so. I've had good luck with Antek's: Antek - PS-10N77R5 (this one has a 5v tap for the logic power). If you use those 1/2" shaft motors, you'll have to either bore out your couplings or replace them with something else that works for both shafts.

Tom makes a good point above - steppers have gotten a lot more powerful for their size lately. There's a bit of witchcraft involved in figuring out the optimum stepper for a given application: more torque isn't necessarily always better, because induction has to be taken into account. All things being equal, I'd say replace like with like, but if you've really got mounting holes for 23-frame motors, and you can find some with 3/8" shafts and at least as much torque, that might be an easier replacement than trying to use something with too fat a shaft, providing their induction isn't too high.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[jjacstcy]

I went with a KL-4813 for the power supply. Its 48v 13 amp. I read that the general rule of thumb for power supplies was to multiply the motor volts which is 2.4 by 20-25? Is that not correct?

[KOC62]

Gecko uses 32 X sqrt(L) where L is in millihenries. So you need to know the motor inductance for the connection type e.g. uniploar, or bipolar or series, etc.
http://www.geckodrive.com/images/fck...cs%20Guide.pdf

[jjacstcy]

Inductance is 4, sqrt is 2 then multiply by 32=64 volt. I went with 48 is that going to be a problem?

[KOC62]

The information given is a guidline, not a law. So what that means is that your maximum speed will be less than a 64V supply. Many use a 48V power supply with good success. Your setup may work well with a 32V supply, for all I know. It often depends on the maximum RPM that your situation requires.

[ger21]

The best voltage to use is the lowest voltage that will give you the performance you need. That way your motors will run as cool as possible. The downside is that it's very hard to determine how much voltage you may actually need.