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Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Sun Jan 10, 2021 7:38 pm
by phazertwo
A little background... I have a small hobby mill that I run an Acorn on, and I love it. It, matched with CNC12 is a fantastic product, and bang for buck I don't think you can beat it. I got tired of the machine (not the control), and wanted something with real rigidity.... So I bought a 1983 Takisawa MAC V2 for a tiny fraction of what I paid for my hobby bench top mill and I need to get it going on a very tight budget. Hopefully after it is running I can sell the hobby mill and pay for some upgrades on the Takisawa!

The Takisawa has a Fanuc yellow cap 20M on the Z axis (18a constant stall, 23Nm, 213v, 1500RPM pulse encoder), and 10M (12a constant stall, 12Nm, 165V, 1500RPM, pulse encoder)

I read that I could run the 10M servos at 80% capacity, but I can't find anything for the 20M servos. I can find that centroid recommends an AC/DC-60 for those (out of a centroid retrofit manual) , but they are $$$. Is it possible to run these off the Allin1 to get started, and maybe upgrade to a different drive later?

Also, I will need a power supply for these. The Centroid rectifier (PN 12726) only says how many in-lbs it is good for... considering there are 8.85in-lb to each Nm, I would need one of these for each drive? Is that correct? It' d be way easier to just know how many amps it's good for!

I'm obviously in the information gathering stage at this point and am open to other options. I've even considered finding new DC drives that can take step/dir and running another Acorn. However that is really limiting considering I will eventually need to get the tool changer working (not right off the bat). I've also considered new motors/drives, something more modern, but it's just not in the budget.

Any help/input would be great. I'd like to stick with centroid since that is what I know (and trust).
Thanks,
PZ

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Wed Jan 13, 2021 5:04 pm
by phazertwo
Can anyone at least answer how many amps the Centroid rectifier can handle? I see you can buy just the rectifier board, which can handle 35amps... but I don't want to assume that the whole package w/ cap. can handle 35 amps...

Thanks,
PZ

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Wed Jan 13, 2021 5:22 pm
by martyscncgarage
From this page: https://www.centroidcnc.com/centroid_di ... nents.html
It can easily handle four 29 in-lb motors.



I wished I could provide more info. I had a friend that had 3 yellow Cap Fanuc motors on a large Comet knee mill and All in One had no problem running it.
I think you are best giving Centroid a call. Have the specific drive model numbers ready.
I would not recommend going with aftermarket drives. DC Brush servo technology is old technology. You should look at AC Servo Drives as a replacement.
You could contact DMM Technologies with details about your motors and your machine, including any belt reduction and pitch of ballscrews.
You could run new DYN4 AC Servos under OAK or Acorn.
The question then becomes the spindle motor and spindle drive. It would be good if you would post pictures of the existing spindle drive and label, spindle motor and label and a shot of the control cabinet.

If it were me, or a client, I would move them away from those very old DC Brush servos. (37 years is OLD for a DC Brush servo)
Just my opinion.
Marty

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Fri Jan 15, 2021 8:59 pm
by phazertwo
In an ideal world, if I had money, I would upgrade to newer servos and drives. I got a quote from DMM before I even bought the machine and they were just under $2500 before shipping and taxes, but I am not sure I really like there servo. I have read a quite a few things about people not being able to run them in velocity mode. Have you experienced this?

At the end of the day, I don't have the money to do all of that, because like you mentioned I need a VFD as well. Then I also need couplers, and to make motor mount adapters and the list goes on. Seems like it would be better to just try to re-use what it has for now, make sure the machine gets up and running and then look at upgrades.

PZ

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Sat Jan 16, 2021 11:07 am
by Arrow
I would be very skeptical of a All-In-1-Dc being able to run those motors. From looking at the machine its not very big and has a huge Z Motor. to me that says it needs a counterbalance and doesnt have one - that it is using a big motor to help hold up the head. Meaning even at standstill Z is probably gonna pull a good amount of amps.It could probably run the size 10s but the combo of 2-10s and 1 highly loaded 20 is asking for trouble. Then on top of that the transformer that feeds the servos pretty sure has 185v secondaries. Thats to much for the Centroid power supply and way to much for the All-in-1. You can reuse the Fanuc servo drives they should be A06B-6047-Hxxx drives. With a MPU11 , GPIO4D and Optic4 it can be done , but not for the faint of heart and for sure not low cost.

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Sat Jan 16, 2021 2:31 pm
by phazertwo
Thanks for the response Arrow! This is really want I was thinking too. I really want to get rid of the Fanuc drives in order to get something more modern/easy to service. Also, I am hoping to have all of this be single phase when this is said and done, and currently (I think) the drives take 3ph.

Thanks Arrow and Marty, looks like I will have to keep looking for another solution.

PZ

Re: Allin1DC and Fanuc Yellow Cap DC Servos

Posted: Sat Jan 16, 2021 3:06 pm
by martyscncgarage
Perhaps you could counter weight the head and use a smaller servo.

Nothing inexpensive about a retrofit. One thing, and f you go DMM DYN4 route, you could run with Acorn and in the future you could upgrade to Oak if you felt the need.
PC and monitor can be reused....
Good luck!