[brbeardm]

Looking for a DC Servo Drive recommendation (affordable $) to drive my 3-axis plasma table...The controller is Galil DMC-2183, motors are Baldor MK-2250-BLBCN. My Baldor TSD servo drives keep throwing over current limits and I constantly have to power them on/off or reset....they are old and my POTs adjustments are highly over sensitive....Can anyone recommend a good affordable replacement?

thanks,
Brian

[Karl_T]

I really like the AMC servo amps to go with Galil cards and DC servos. I have several on the shelf to sell if you are interested.

I have both a CNCmill and a CNC lathe running these amps with galil cards under Camsoft


EDIT here's a table from AMC to help pick the correct amp

[brbeardm]

Great, I am using Camsoft as well... If you have any servo tuning tips, please let me know.

On Wiring, I assume the Galil ICM-20105, PIN 14 - Motor Command (axis) goes to the +REF IN pin 4 on the AMC?
any other specific wiring I need to do to make these work?

For my Baldor motors... they are:

Max Voltage: 40 VDC
Voltage Constant: KE 7.4 V/K RPM
Current Cont.: 5.5 Amps
Current Peak: 30 Amps
1000 L Encoder

Based on this and your table... looks like I need the: 30A8.

Are these used/new drives? Im interested in 1 right now... then once I confirm it works... I would get 2 more.

thanks,
Brian

[Karl_T]

I don't have any that big. WOW, why so big for a plasma table??? I move a milling machine and a lathe with much smaller ones. AND you over trip that??

For wiring I will share the Hardinge. Look for X servo or Z servo in device 2 column...


EDIT just looked, I have several 25A20s 25 max 20 continuous. $100 shipped if you want to try one. you need a dc power supply to run these, I assume you already have that. If not make sure you are right up to the max voltage or even just slightly over. more volts means less amps.

Are your accelerations set too high???

[brbeardm]

I may need some help there then sizing this amp to my motor specs I'm just scoping it based on my motor's Peak Amp rating... The continuous AMP rating is 5.5, should I size based on that and try a 12A8 with the 6AMP continuous... What do you have and do you have the power supplies as well?

[Karl_T]

Yep, 12A8 is what I use on two machines. Especially the mill moves a lot of steel, but i do not use out of this world accelerations. IMHO hi ACs just tear things up, you are not going to get any huge productivity increase. Guess I'd let you have a 12a8 for $75. Got a dozen on the shelf. I can email you an install and trouble shooting manual.

Just buy or build a 40 volt DC power supply.

re: servo tuning. What Camosft provides is not much use. BUT you can tune them directly under Galil Tools. They have tons of how to articles on their web site. The auto tune routine normally works. Also look up Jim Dawson (moderator here) for help. He has forgot more than I know on Galil cards.

[Jim Dawson]

I think Karl may have hit on the over current issue. The acceleration might be a bit high. On the other hand, I understand that hard acceleration makes for better cuts in a plasma system, so beefing up the drives might be a worthwhile endeavor.

I don't know what control you have from CamSoft, Karl is the expert there. But in the Galil you control the Acceleration and Deceleration with the ACn And DCn commands, where n = the axis letter.

[brbeardm]

Any suggestions on the 40VDC power supply? How about this 48VDC model on Amazon?

https://a.co/d/h5GohG8

[Karl_T]

no where near enough amps.

maybe this
https://www.ebay.com/itm/13448046870...EaAnI6EALw_wcB

or maybe two of these and set to exactly 40v
https://www.ebay.com/itm/36443857976...3ABFBMjOOj5sli

[brbeardm]

Thanks Karl,

so to clarify...on the "or maybe two of these..." comment... is that 2 per axis? I think 2 40V sources (in parallel) would combine their amps, right but total voltage would remain 40V?

and so my Baldor servo motors are 40VDC Max, Current Continuous 5.5A, Current Peak 30A ...what's the theory on matching this to the servo drive power so I don't burn the motors up?

[Karl_T]

no, I would put one supply on each amp, separate. You will get far more efficiency if you got to the max voltage allowed.

You have a Z axis? Need to see you machine but maybe this could go with the a xis that does not have the gantry. or get one supply for each axis.

Did i tell you I got 25A20 AMC servo amps???


I did not see 30 amp dc supplies on a quick ebay search. with the above, the DC supply is the weak link if pushing servos to the absolute max. Maybe look for switching DC supplies that will do 30 amp and 40 volt. Both mouser and digikey should offer them ( bet quite a bit more $)

[brbeardm]

Ok, thanks Karl.

It's an XYZ plasma table I'm building. so I have all 3 motors unloaded right now from their axis and I'm just trying to get everything working one axis at a time... I've started with Z-Axis. A buddy of mine here in Houston let me borrow a 12A8M for a few weeks so I hooked it up yesterday with my 1 power supply that came in. (Switching Power Supply 1000W DC 36V 27A Power Adapter Driver Transformer 220V110V AC DC 36V)

I can't get the motor to tune with Galil Design Kit...Can you help me confirm a few things:

1. With Galil, I should be in "Current" mode on the 12A8M for the +-10V command signal?
2. With Galil, the "Motor Command Z-axis" pin goes to pin 4 "+ REF IN" on the 12A8M
3. With Galil, "Ground" goes to terminal pin 5 "- REF IN" on the 12A8M

I did not think there is anything else I need to wire, right... or Do I need to wire AMPENABLE?

adjusting the POTS are strange... any tips there to get to a starting point?

thanks,
Brian

[brbeardm]

so update: I reversed the Command Signal Z-axis going to pin 5 "- REF IN" on the 12A8M and "+REF IN" to ground and I'm able to go through the Galil Tools tuning programs pretty well.... is this right, seems confusing to me....

also when the motor is stopped, I get a little bit of chatter on the axis encoder position, kind of rumbles slightly.... but once I pick a test in Galil tools, it' quiets and runs the test.... is this normal?

[Karl_T]

I really struggle with tuning and always end up asking for help. Jim Dawson saved my a$$ last time. there is A LOT of great tuning info on the Galil website.

On the ref in, you may have the encoders hooked up backward. the switch you did just reversed the +/- 10 volt signal. Did you check encoders by hand first? that is rotate in positive direction and encoder counts go positive? There is also a galil command(CE ?) to reverse encoder direction.

There are also gain pots on the AMC servo amps that must be tuned before doing anything in galil tools.

If all of the above is correct, I believe chatter at stop means adjust integral gain. again, I am rusty and would have to read up on it again.

RE amp enable. I always wired that up on my installs. Then used SH command to enable amps and MO to drop them.