Fanuc 6M DC servo

[DGA]

I am trying to drive a Fanuc DC servo, a 6M, with an Allen Bradley drive, AB 8400 system. Wondering what that servo has for it's position feedback, is it an encoder, a resolver or? The servo has the same voltage as the AB, 150 VDC so that part of it is good, and it is also a brush type so good there too. I believe my AB system uses encoders, how would I tell for sure? Thanks for any help, DaveA.

[tc429]

take the 2 screws out of the yellow cap, and look inside...its either got a pulsecoder (most likely) or a resolver and tach.

I'm not at all familiar with AB controls, dunno if they need a tach. Fanuc didnt have a tach if they had a pulse coder- they used a frequency:voltage converter on their control to emulate the tach back to their drives, either 3.5 or 7 volts per thousand RPM was set via jumpers on the drive/controller. if you need a tach, this could be a issue.
Pulse coders came in only 2000/2500/3000 line resolutions- should be a tag under the yellow cap, or if the original tag on the motor is intact, the last digit says what encoder...-B001=2000, -B002= 2500, -B003=3000...any numbers in the tens or hundreds positions indicate other hardware, like a
-B201= a 2000 ppr encoder and a brake... encoders were A-B quadrature with Z marker, all complimentary outputs

are you using the 6047 Fanuc drive, or trying to control it with a A-B amp?

[DGA]

I don't have the servo in my hands so I can't look under the cap, bummer. The servo says Type A06B-0642 on the tag and then stamped 013 after that. Date code is 85 if that means anything either. I have an Allen Bradley controlled Lagun knee mill, with 1388 AV10 amps, and it is 4th axis ready so was hoping if I could find a servo that I could get to work then I would adapt that to a rotary table and then consume many dozens of hours trying to get it all to work happily together.

[tc429]

just looked up in my antique order guide from 1987, I was wrong-

B011/B012/B013 are 2/2.5/3K encoders in the M series- description of your motor *I think* is

A06B-0642-B013 model 5M motor with 3000 pulse encoder-

your part number mentioned was missing the 'B', I believe all Fanucs had a B in them... what kinda sucks for a rotary, most tables are set up for 2 degrees per rev...unless your AB can scale input, youd probably want a 2000 line encoder.

(the b001/2/3 I mentioned first were the codes for the resolvers/tachs)

I never noticed till now, they DID offer encoders with tachs, those were B081/B082/B083.


you sound kinda similar...I have a Bridgeport I want to put the 4th axis on...built one from a tiny harmonic drive for a small robot, got a little 3 or 4 inch chuck on it from Enco, but I dont have a extra fanuc drive for the little fanuc dc servo...I have a couple other drives I think will work, need to work on that like another hole in the head...had that machine runable in the garage since around 95, spent a small fortune refilling the gutted Fanuc zero-A freestanding cabinet/wiring/writing ladder for a cheap Ebay 15M operator panel...never did more than a few hours work on it, had the kids 'programming' to engrave their names in little blocks of wood, and a few R/C heli parts... I just have a soft spot in my heart (er-head) for old stuff...just 'had' to save it from the scrapheap

[DGA]

The last stamping I think says 3000, and it is a model 5M, so you hit on it right I believe. I will look tomorrow and see if I can find anything in the AB control that says about being able to scale inputs. Sort of impressed with the AB control, it is quite user friendly for an '89 model, lot easier than a Fanuc to set up a job for sure. Must have been cutting edge back then with a colour screen and all.

[DGA]

So, this one I think is no good with a 300 line encoder. thanks for the info. Can you tell me, what are the smaller Fanuc servos, the smaller model numbers like a 5M etc is smaller than a 6M? And which ones are about 150 VDC?

[tc429]

rather than change motors, maybe just find a 2k encoder? watch Ebay for deals. I found the op panel for my mill on Ebay for like 200 bucks, and it cleaned up absolutely like new.
the encoders are just a bolt on part, just take the 4 screws out of the amphenol plug, gently pull the cable out, take the snapring out of the backside of the connector(just need a small pick), push the plastic part back in (if its not already,tape it together- if the outside half falls off, the unused pins will fall out- and theyre kinda fun to slide back together), then take the 2 screws off the yellow cap and remove it. there are just three phillips head screws that hold the encoder to the motor end bell...theres a brass oldham coupling in there, keep it - a new encoder wont come with one.
you *might* find a fanuc parts repair/rebuilder willing to give a fair trade in on your old encoder- 2000 line are ultra common, 2500/3000 are a lot less so...might be hard to sell, but then again, those guys like to have one of everything available...if you remove it, be gentle- they use a very brittle glass disk, drop it even a couple inches it will break. if you replace it, put heavy grease on the little brass oldham coupling- if its even a thou loose it will make for a buzzy motor, grease damps it pretty good.

btw- the 0m/5m are similar mounting dimensions...aside from shaft options, they normally interchange- only difference is the black part of the shell is shorter on a 0. (similar with 10/20/30- all use the same mounting dimensions). the 00m is a little pop-can sized thing, thats what I'm going to use for my 4th axis. I think 00 used a different encoder, as the encoder bearing is also the motor rear bearing- but size 0~30 m all had the same encoder mount.

as far as motors, heres a scan of the old General Numeric M-Series flyer:

[DGA]

Sorry, slow reply. Thanks for the chart, very helpful. Can you tell me, how many wires are actually used from the encoder, so that aI might try to see if a similar amount are used on the AB system. I do have a wiring diagram for the encoders on this thankfully. Also, how would I figure out which of the 4 motor wires go where?

[tc429]

if youve got the diagram, should be ok...from memory, if youve got the 20-29 Amphenol, the pinouts were A/D and B/E pins are A/A*, and B/B*, G/H are Z/Z*, CJK are +5, NPT are 0V (doublecheck your drawing- its been a long time) R/S are normally closed thermostat contact. I think there was also a smaller plug on some motors, but think it only came with resolver/tach options. your biggest issue might be the lack of tachometer- Fanuc used a freq/voltage converter in the axis LSI to emulate the tach...

[DGA]

Well I ended up getting a different one. It's an A06B-0642-B005-R, in good shape I think. Can't figure out what resolution that is.

[tc429]

MCS has Fanuc Cnc Parts, Ge Fanuc Parts and General Numeric Cnc Repair.

this site says its 2000 w/tach

[tc429]

uh-oh

pulled out my old order lists, it says thats a tach only/no encoder

Tim