Confused on a Servo Motor spec.

If you just need some analog drives (ie +-10V) then I would suggest picking up some 25A AMC drives off ebay. That's where I got mine (BE25A20ACG-INV these actually have thier own power supplies but are very large and you need a PC cord for each one), only paid about $70/drive on average. Granted there is no warranty in this situation other than what paypal/ebay offer but you still get support from AMC to some degree and these drives can take some abuse.
NOTE: if you do decide to get AMC drivers keep in mind the cheaper ones control trapezoidal motors only! This means your motors should have hall sensors. If they do not have hall sensors than you would need a sinusoidal driver.

Newer AMC drivers are designed for sinusoidal motors, it is unlikely you will find too many of those on Ebay and certainly not under $400/drive.
 
If I remember correctly, you are using Mach3 on your other machine. If that's the case, then I would be tempted to put closed loop steppers in and run it on Mach3. ( I meant to say closed loop steppers in my post above) As Dave2176 suggested, the motors from Automation Technology or equivalent would be a good fit. 1100 oz-in NEMA 34 motors should work great. If I were building a Mach3 driven system, or even converting a machine to my software I would be taking a really hard look at those.

Another DC servo drive option is Fenner (Servo Dynamics) SFD 1525-12, that is what I have in my machine, with about the same Baldor motors. There are some 3 axis drive units on ebay. SFD 1525-12-3
 
All I can say is THANK YOU, thank you , thank you Jim. Appreciate your support and dedication to this site and helping us all out on your own free time.


JimDawson said:
If I remember correctly, you are using Mach3 on your other machine. If that's the case, then I would be tempted to put closed loop steppers in and run it on Mach3. ( I meant to say closed loop steppers in my post above) As Dave2176 suggested, the motors from Automation Technology or equivalent would be a good fit. 1100 oz-in NEMA 34 motors should work great. If I were building a Mach3 driven system, or even converting a machine to my software I would be taking a really hard look at those.

Another DC servo drive option is Fenner (Servo Dynamics) SFD 1525-12, that is what I have in my machine, with about the same Baldor motors. There are some 3 axis drive units on ebay. SFD 1525-12-3
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Thank you for the kind words, it's my pleasure to help out.
 
Thanks so much for the help. It's 1:1 on a belt drive. the owner noted that it's set to 120ipm and when you work that all out, it's plenty.... Of course, via reading and the "sales wonks" plus the hype - You hear they all want 2K 4 channel or 8000PPR ....And to do that is going to be invasive.

So, I'm learning. Love that part. I'll see if I can find the ball screw spec. I may have that here. hold a e-sec.... Nope. nothing in the YCM30 mechanical manual. But will keep checking.


dracozny said:
depends on a few things. are you doing a belt drive or Direct coupling? with a belt drive what is the max speed you intend to run the motor after calculating your typical feed rate?

if you had a .25" pitch ball screw attached to the motor it would result in a smallest increment of .000125", if your max required speed is 2000rpm. this would only require a system capable of 66Khz which is well within a 5i25/7i77 combo capability, I'm sure any motion controller board would be able to handle it as well.

The limitation of the muxed encoders on the 5I25/7I77 is maximum count rate. This count rate is 2.77 MHz on the 5I25/7I77 (with encoder filter off) and 555 KHz (with encoder filter on) These (with a safety margin added) limit you to about 12000 RPM and 2400 RPM max with a 2500 line (10000 count/turn) encoder. Usually the encoder itself will limit you to lower frequencies.

As you can see with the above example, 2000 PPR is almost too accurate. If you go with a belt drive with a 2:1 ratio or more than a 500 PPR would be more than enough although in this case you also now have more points to create backlash.

With all this said, I do have a 1000 Pulse quad/diff encoders on my motors which is 4k PPR on 5mm lead screws with a 2.36:1 belt drive equals .000116" PP. Over engineered and $$ for a zx45. Just some things to consider.
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