[cbucner]

Here we go!
I was looking for a CNC mill for retrofit for a long time and finally I found one.
It's inside the garage now and I'm planing on starting this project ASAP
I'm new to CNC and I'm starting this thread with hope that I will get some help and sugestions in what direction to go.
For the start here's the mill
It's a 3hp Spindle motor, 110v DC Servos .
Now I don't know where to start this retrofit.
I was thinking to use Gecko drives but they are limited to 80v DC , the servos are 110V and I really like to use the ones on the mill.
I tried them with a 12v battery and all of them work perfect , I could not even holt the table only on 12v power to the servo.
I'm wondering if 80V will be good for the servos to run or i will not take advantage of the full power ??
Second from what I read gecko drives will do a 70V MAX If you don't want to destroy 'em.
Any sugestion here will be much appreciated.
Next I was looking at Rutex drives, they have 100V 20A drives which will be a better choice I guess, Any of you guys are using these rutex drives and how they work??
Third I'm trying to understand what kind of power supply will give me 70V ??
at around 20A because each servo is rated 5.8 A.I was thinking that if all 3 will run I will need a 20A power supply .I was looking online and the biggest power supply was 48V. I'm new to this field and I'm trying to understand all this in a short amount of time.
Any sugestions here will be much appreciated.
Here's a shot of the servo
They are direct drive to the ball screws on the table.
Only the quill screw is on a belt drive from the servo.
Now I want to understand how these encoders work.
The mill has 3 groups of wires coming out of each servo.
There is a black and red pair, which is the power to the servo, next there is another pair in a copper wire mesh screen which I guess is the tach , forgot to mention each servo has a tach and encoder, and then there is the encoder wires which I'm lost , there are 3in one pair with a ground looking wire, and another 2 in another pair with the same kind of wire.
Here's a shot:
Any directions here or what are these wires will be a help.
Can I use this kind of encoder with a gecko or rutex drive??
So that will be it for now any sugestions of where to start will help .
Here's a shot of the spindle
Thanks and I'm waiting for some replies so I know where to start this whole process.
I will post pictures of all the progress so it will be easy for new guys like me to understand What's going on.

[damae]

Welcome, fellow Shizuoka owner!

I just bought almost the exact same machine, the A-NS! There are a few of us here with the same mill, including Barry_Ward and HuFlungDung. Barry's post is here:

http://www.cnczone.com/forums/showthread.php?t=21448

I haven't completed my research, but right now, lean toward the Rutex drives for the same reason you are considering them -- higher voltage.

[cbucner]

I had a choice in between AN-S and ST-N , I went with ST-N because of the size and weight.
The AN-S has around 1000 lbs at least more and it's way bigger.
I wanted something that I can move around easy and I guess that the ST-N it's the smallest .
So did you start your retrofit yet or not??
I went to Rutex but they are out of stock of some items for about 4-6 weeks
What's the dif between optoisolated and non optoisolated??
I guess that it will not fry your lpt in case of something goes bad??
The optoisolated are 4-6 weeks wait time.
I can get the other version and use an older pc just in case.
What about the power supply, the 100v 20A???
A closer look under the hood DID you guys figure those encoders out??

[Al_The_Man]

If you are looking at 100v drives, what is the voltage your present power supply is putting out?
If you are feeding the same motors the power supply should be adequate, if it is a little high in voltage then the cheapest way might be to put a buck/boost transformer on with the secondary (buck) in series with the main secondary and the bridge.
Al.

[cbucner]

Hi AL, I was looking for your reply in the VFD section of the forum regarding my VFD for the spindle motor.
Anyway Here's a shot of the original control , I'm scared to even check that transformer , it's full of dirt!!!
And I atached a shot of the spindle motor for that VFD question.
Thanks AL

[Al_The_Man]

I would take the power supply out and wash it off with one of the electrical cleaners used for this purpose and see what is salvagable.
Unfortunately it looks like you have resolvers there, I would assume they are geared up separately, as I wondered why they did not appear to be on the motor?
You will need to replace them with encoders, preferably on the motor shaft.
If neccessary or possible you can take the tach's off as you do not need them with modern drives and see if an encoder can be fitted in place of.
The motor can be fed with a VFD 1ph 220v in and 220 three phase out. You should be able to run this up to 120Hz this will give you double motor speed as it is a 4 pole motor.
It pays to get a good VFD, you generally get what you pay for, the better ones have flux vector feedback for speed control and have things like auto tuning etc.
I have had good luck with ebay in this area, using WEG, Mitsubishi and Square D Altivar drives.
Al.

[damae]

Aha, so the ST-N looks very much like the AN-S! At least your Bandit control and servos look identical to my machine. Unfortunately I don't know the answer to your question about the motor encoders, although I plan to go the same path (Rutex + original servos).


If anyone has the answer, you'd be helping at least two people out!

[cbucner]

One of the servos has the encoder on the back of it , check this picture.
Here's the writings on the ones pictured before

Summit Eng. Corp.
Model 573-211-10
2500HZ
Rotor 1 Phase output 6.0V
Stator 2 Phase input 12.0V
Spec. Code. H.S.C.I. 11 BRW-300-F-70/10

And

Sierracin/Magnedyne
Model 707-01A
Serial 2304

So AL None of these are encoders??
Here's a closer shot of how they are located and the ones on the back of the servo
Any input is appreciated

[Al_The_Man]

One of the servos has the encoder on the back of it , check this picture.
Here's the writings on the ones pictured before

Summit Eng. Corp.
Model 573-211-10
2500HZ
Rotor 1 Phase output 6.0V
Stator 2 Phase input 12.0V
Spec. Code. H.S.C.I. 11 BRW-300-F-70/10

And

Sierracin/Magnedyne
Model 707-01A
Serial 2304

So AL None of these are encoders??

No, it looks like all are resolvers.
You will notice that they are probabally geared up off the motor shaft, due to resolvers not being as high a resolution as obtainable with encoders.
The wires coming out of the grey cover look like two wires, tach maybe?
Al.

[cbucner]

The Sierracin/Magnedyne is indeed a Tach.
I found some info aboutit and it's a Tach.
Now the other one means is a resolver.
What now??
encoders?? What kind Where to mount??
Thanks

[Al_The_Man]

I favour the through-shaft type, but they require access to motor rear shaft, otherwise it means separate encoders with helical or similar couplings.
There are US digital or higher quality Renco, but again you get what you pay for.
Al.

[cbucner]

I did a search for encoders and I found dif types,
I think best will be a shaft type one andtry to install it in the palce of the present resolver.
I have to remove the resolver and see what's going on in there.
Now AL what will be a good encoder?
how many pulses/ rev will give a good feedback.
Thanks
I'm still trying to find more info on that resolver or whatever it is.

[Al_The_Man]

It depends on the system you are going with and what resolution they accept.
For the systems I am involved in I use a min of 1Kp/rev.
You may have a problem replacing the resolver with encoder in the same position due to the miniature shaft and dia of the the resolver.
Al.

[cbucner]

here we go AL .
This is what's going on :
the one with the flanges is the tach, and the one without is the resolver(whatever it is soon to find out)
Thanks AL for all your time man.I appreciate that.

[cbucner]

After some research I finally found that the mistery is indeed a resolver.
Good job AL.
Here's a site wich has some info.Looks like mine is a size 11
http://www.amci.com/resolvers/size-1...-resolvers.asp
And a tutorial of what a resolver is
http://www.amci.com/tutorials/tutori...s-resolver.asp

From what these guys are saying reslvers are usesd where tough conditions are present.Kinda like a heavy duty encoder.

Now is there any servo drive that is using these resolvers or encoders only??
I'm on my next question mark.
Thanks

[Al_The_Man]

The main use for resolvers now is in AC sinusoidal drive commutation.
For feedback, encoders are predominantly used now.
The resolver had the feature of noise immunity, but suffered from low resolution, hence the gearing.
Al.

[cbucner]

Hey AL what do you know about these BEI encoders.
I see em on ebay and I called BEI, they are pricey no kidding.
Renco are cheaper , US DIGITAL even better.

[Al_The_Man]

BEI are one of the heavier duty encoders, they make them for Allen-Bradley, re-branded.
I would suggest only buying new encoders off eBay as I have been stung a few times with used.
The Renco are cheaper and still use Glass scales, the US Digital are about the cheapest in price and quality, I believe they use mylar scale material.
Also very good if you can get NOS is Heidenhain & Hengstler, both top-of-the-line.
Al.

[cbucner]

Thanks AL
I'm going with US DIGITAL for now but i'm still trying to figure out what CPR should I get??
What will do a good job for a mill??
Have no Ideea.
THanks

[Al_The_Man]

What you need to know is where the encoder is fitted, (final counts/rev) and what the system you are using will allow, and what resolution do you want/need.
For e.g say you have an encoder on a motor which operates a .25" pitch ball screw directly.
If you had a 1kpulse/turn encoder and most controls will allow increasing this resolution on a quadrature encoder to x4.
Therefore this will result in (4x1000)x4=16,000 pulses/inch which equates to a resolution of .0000625 per pulse.
If you have any gearing between motor and ball screw this will affect the resolution proportionately.
Al.