Hi everyone

I have a Mazak M4 that I want to retrofit with a centroid controller.
I would like to use my existing servos, as they are huge in good working order and seem to have special shaft configurations. Ajaxcnc advise that I should be able to use them, but would need to chage out the resolvers to encoders and provide new servo drives. Does anyone know if this is an easy task, and what type of controllers might be required?

What system was on the M4, it could be Fanuc or Mitsubishi, both used similar DC motors on their early systems, which were based on the Gettys motors. Do you have specs on the motor labels and does Centroid offer analogue (+-10v) amplifier control?
Al.

Hi Al_The_Man

The Mazak has a Fanuc 5T controller complete with fanuc motors. I am not sure on the specs, as there are no real lables on the motors and no info in the Fanuc books.

The x axis motor is about has 146mm flange while z-axis is huge with 240+mm flange and about 35mm shaft. Both have currently resolvers installed on them.

Centroid do supply dc amps, but I am not sure if they are big enough.

I can probabally get the ball park, they should have model 2 or 5 or somesuch,I meant does Centroid have a analogue output for 3rd party drives as you might find one of the AMC largest amps will do the trick, if the original motors had tach's on them, you can probabally do without them now as modern amplifiers are run in the Torque mode with the loop closed via the encoder only.
Also, if you obtain amplifiers that need a power supply, unless you are selling them, you could cannabalise the old amplifiers for the power supply, they are parobabally three phase at present, or are you planning on running on 1ph?
Al.

Hi Al

You are right they are called something like that I will look it up at work later today.
Ajaxcnc recommended I look up the AMC amps. I was planing to run in torque mode.

But how easy is it to swap out the resolvers with an encoder?? Do you know if the Fanuc motors have appropriate facilities to mount new encoders??

I was planning to replace the old amps and power supplies, just for ease of retrofitting. I had not thought of using the existing ones, which would definately be 3 ph. Do you know if modern amplifiers will run those motors without any problrms??

Craig

The resolvers are usually run off of a gear wheel to increase their resolution, you will have to find a way to mount an encoder off the end of the shaft, either by solid extension and use a Renco shaft mount encoder, or use a encoder coupling to a separate style encoder and make up a mounting, either way requires some minor engineering.
The AMC amps should have no problem with these motors, going by the size of the motors, you are going to need quite the power supply for 1 phase.
Did AjaxCNC tell you what they output in the form of amplifier control signal?
Al.

Thanks for the info. I believe the motors are in the 20 - 40A range, so I intend to run them of 3ph.

I thought that the resolvers were mounted in the back of the motors do they have some sort of gear mechanisem inside of them to work?

[ Did AjaxCNC tell you what they output in the form of amplifier control signal? ]

Do you mean +/- 10 V or something else.

Craig

IIRC they are geared up about 10:1 because of the fact that resolvers are relatively low resolution devices compared to encoders.
Yes, 10vdc+- was what I was after or do they use other methods?
If you are running off of 3ph then I would look into seeing if the existing power supplies in the drives can be salvaged and you will also be getting the same DC level for the new amps. They usually consist of a three ph bridge into a capacitor supply if PWM, unless they are SCR control across the 3 phases then you will be out of luck.
Al.

I am sure they use +/- 10 volts for control.

Why do you suggest seeing if the existing power supplies can be salvaged? Is if for cost reasons or compatibility reasons?

I am not sure what the PWM / SRC bit means, I am no electronics expert, thats why I was hoping to replace them with of the shelf items.

Craig

Amplifiers can come with or without power supply, the type without can give the option of one large power supply for all three, but with the kind of sizing you have it might be prudent to go with a power supply for each, as per the originals.
The thing is that large amplifiers with built in power supplies puts the cost up quite a bit, So by using the power supply part of the existing amps, gives you a bit more flexibility in chosing amplifiers, saves money and provides voltage compatibility with the motors. If you post the part number of the present amps I may be able to tell you what type they are.
Al.

Thanks for the great info Al. I will have to make a trip into work to see what I can dig out on serial no's. I will have to get back to you in a couple of hours. I can assure you I am all for saving money on these items and it does seem pointless to waste them, as they are working just fine.

Here are some photos of my Mazak and servo drivers (I think)
It seems the motors are Gettys type 10 and 20, 15A & 30A respectively.
Would it be suitable to reuse the amps?? and how difficult would it be to rewire those to new drivers?

It should be possible if the amps have analogue control, I believe that vintage does, do you have the Fanuc model number? Do you have all schematics for the machine?
Al.

Hi Al
I have some of the electrical diagrams photocoppies only, so I am not sure if they are complete. The fanuc is a 5T, would you know where I might look for the model number?

I could not find any numbers on the servo drivers.

I will have a quick brouse through the manuals.

Craig

The numbers will be like A06B-6045-? I assume you will also want to re-use the spindle drive and motor? It looks like it has a fairly large DC spindle? That should be easier to integrate to the new system.
Al.

The 3 pictures that you posted were taken of the insides of the control were taken from the REAR of the 5T cabinet.

The two fotos in the upper left of your foto spread that have fuses and a contactor on them are just that: fuse panels and contactors for the power to the servo drives and to the servos themselves.

These are NOT servo controls but the power source protection stuff for the servos.

The third foto that has a big square PCB on it with the black plastic cover going down the middle with the fan on the bottom is the DC power supply for the entire controller. It supplies and regulates the various +/-12, 5v, 5vreg et al DC voltages needed for the system.

Don't mess with it. If you can loosen some of the connectors, all sorts of ugly expen$ive things will happen.

The servo drives are mounted on the OTHER side of the cabinet.

Open the front cabinet door (the one with the control buttons) and the two PCB's that you see in the upper right corner of the cabinet are the servo drive cards/amps.

Two small Honda connectors come our of the lower left corner of these and plug into the upper left corner of the "A" motherboard. These are the drive and feedback wires to/from the servo amps. I have the pinouts someplace.

I believe that I have the schematics for both the servo cards as well as the "A" boards but have never taken the time to figure out how they work.

The amps do seem to have integrators on them. THe mother boards definitely have DAC's on them that are found on the APC-06 IC's that are on the upper left quadrant of the "A" board. These are REAL pricey IC's.

They may be +/-10 or such controlled but I AM NOT POSITIVE. I DON"T KNOW HOW OR IF THEY ARE RETROFITTABLE TO CURRENT PC's.

REMEMBER: the Fanuc 5T was late 70's vintage hardware and all the digital circuitry is pretty much 7400 series TTL. Old and obsolete and getting real hard to find IC's to service them.

My experience with Fanuc is that, due to the age of the systems, Fanuc is hard pressed to answer questions. Most of the service guys at Fanuc today were'nt even born when these controllers were made.

There is an outfit in Texas near Houston or Dallas that services them and does so at a reasonable cost. Contact Billor Ent. and ask for Glenn Roe - they have a website.

There is another gentleman in Ohio, who was a former Fanuc service engineer. He has a website (Suburban Machinery Software, Inc. and his e-mail is subsoft@buckeyeweb.com). He posts a lot on MMSONLINE.COM messager board for CNC/DNC.

I"m pretty sure these servos are pretty stout and I do believe that Fanuc still services them. Resist the temptation to take them apart as they need to be factory realigned after reassembly.... :drowning: That is unless you are goind to install your own power supplies, encoders drives, et al.

After trying to resurrect some CNC lathes with these same contols and drives, if they work, you may want to leave them alone or else prepare for a major thrash to upgrade

Hi NC Cams

Thanks for the insight. We ended up replacing the Fanuc amps with Rutex amps, partly due to integration concerns and also because I decided to run with Mach3 software so we needed step and direction input. We are about to do another machine and again we will be replacing the amps. From what you have mentioned they are far to difficult and old to try and integrate.

Craig

Old? Yes.
Difficult to integrate? That depends.

IF you have the drawings and know a bit about electronincs and/or have friends who knew how to work with 7400 TTL circuitry, it isn't that hard.

We were lucky enough to get lathes that had full documentation with them. Why? One was a brand new unbuilt demo chassis w/o controller, one was a very lightly used show lathe with a toasted A board from a bogus BTR and two were operating on a shop floor.

We were even luckier to find a guy at Billor who will bench test and service them for a reasonable price once we started to resurrect them. We've even been lucky enough to find operating controls that people were scrapping out and picked them up for peanuts.

Just curious: what brand of retrofit are you planning to use???

Hi NC Cams
We ended up settling on Mach 3 with Rutex drives and Peter Homans Modbus to drive one of the turrets and a new AC spindle motor with VFD. Sort of a commercial hobby retrofit. It seemed the easiest route at the time, we reused parts of the original power supply, but certainly cut out a lot of the old electronics and and space.

Regards

Craig