Centroid Community CNC Support Forum

Gary, and other experts...
I know you are the expert on this subject, I have asked in the past about motor drives I have decided that I want to update them
I currently have gecko 203v's I was doing a bit of research here and on the web, my question to you is which drive to use?
I know there are several models that have the correct voltage etc. to run the current motors I have.
they are 50v dc 6 amp nema 34 450 oz in motors. running a 4 to 1 belt reduction with a 30 tooth pinion.
I was looking at the DM870 drives, do you have a recommendation or a suggestion ? or somewhere that I can look for more info?

thank you,
Charlie

I am not an expert, but the 556 would probably be plenty for your current motors and power. It sure would be a good time to change motors also. What machine are you using? Maybe a few pics of the machine setup would help.

Charlie...
There are a number of products that will replace the lizards. The 2 that spring to mind are the DM-860 and DM-870. The DM 860 are a bit larger form factor and may work a bit better with your motors as the ozin/Amp ratings look like the numbers from yesteryear. You might want to consider going with more modern (and matching) motors for a few more bucks.

Don't know what you exact needs are, but open loop products seem to be going down in price. The future is closed loop/servo with EtherCat. That said for a " couldn't lose a step if I wanted to" open loop system I would try the DM870's with 971 ozin (5.6A) on a 60v switching or 68v toroid power supply. I would also drop to a 24 or 25 tooth pinion. That gets you a real "stump puller". The turns per inch is still just over one (I like 1.5 or higher) but can get you 2.5 times the torque and raise the rez to over 3200 steps per inch. (.0003 step rez)

Cross post edit: The DM-556 are 5.6A peak and 4A continuous, not enough for 6A motors

Gary,
thank you for the help....ken as well there are photos of my machine in the gallery if you want to see it...
I will look into the stepper motors as well is automation technologies a good place to source these parts I
believe I read that their motor drives were rebranded leadshine??

thank you,
Charlie

Charlie...
John at AT has good stuff, but I buy genuine Leadshine from www.americanmotiontech.com

Gary,
thank you for the help,
I will check them out..

Charlie

Charlie...
They are the only "approved" reseller in the US of genuine Leadshine products.

I have a set that were from cncrp and labeled 7amp max. The board inside tells me leadshine 556. They are about gecko size and not the large leadshine that I''m used to seeing. All of the systems I've piddled with have been set at a lower amp rating than the motors list. Should I bump em up?

Charlie.G wrote: ↑Mon Sep 09, 2019 10:56 pm Gary,
thank you for the help,
I will check them out..

Charlie

Another source for some Leadshine products is www.cnc4pc.com
Arturo Duncan is good people and has been in the business for a lot of years. He is working to develop accessory boards for Acorn. I recently used some on a 2x2 Phoenix router project I did a few videos on. It did making connecting the DMM DYN2 drives pretty easy.

Marty

There seem to be quite a few closed loop Leadshine clones around these days, not least the "integrated easy servo" style, where the driver is actually integrated with the motor / encoder assembly. This makes for a neat and robust solution.

There are also integrated servo motors coming available in a very similar packaging concept (eg from JMC http://www.jmc-motor.com/ntegratedservomotors.html) which integrate a brushless servo motor, encoder and servo driver in one package. Being a true servo, you get a decent speed range (typically 3000rpm) and broad torque range. I like the look of these....

Steppers tend to be sold on the basis of the maximum (stall) torque. While that peak value may sound impressive, the motor torque tends to fall of very rapidly with increasing speed. If you plot the power vs speed characteristic (rather than the torque vs speed), you tend to find that they are pretty much constant power in nature, so if you double the motor speed, as often as not you half the motor torque. The practical implication of that is that you might as well couple the motor directly to the leadscrew rather than gear it down using reduction pulleys. By doing do, you operate at a lower motor speed where the torque is higher, giving a very similar end torque (at the leadscrew). You also increase the (unloaded) rapid speed for free. The only significant reduction is in the stall torque, where the motor is fighting against an immovable load. In this situation, you are most likely not actually machining anything and are more likely to damage your machine if you have a big reduction ratio. Beyond that, direct coupling the motor may reduce your resolution, depending how many steps per rev you have available. On the upside, closed loop stepper drives are more capable of delivering the available torque at the higher steps per turn, unlike some of the more basic open loop drivers.