[sumonetoo]

Over the years I have junked several cnc machines due to lack of room , too big ,too heavy , whatever the reason. I have saved parts such as servo motors , spindle motors, etc.
mostly red cap fanuc motors . I have coupled up cheap chinese inverters to some 3 phase motors from tool changers, magazine motors to drive drills and bandsaws . Once they work seem to work for years no issues at all . My drill presses tap without tapping heads for example.

It would be amazing to be able to drive a fanuc servo motor with a power supply, some SCR's and an Arduino for example. I haven't really seen anything simple enough on utube for me to understand.
IF, and it seems they do, need feedback to stay live and a high frequency signal then that's probably why no one used them with out a matching drive (because you cant).
I do have the a bunch of servo drives from the same machines. Perhaps its too tricky since it seems several parameters have to be "known" by the drive to make it move correctly. Writing this I think servo motors are going to be way too much trouble. I'll keep them for to replace on working machines here but so far never had one fail.

Spindle Motor!
How about a 8000 rpm (max) fanuc 200V spindle motor do I need a lot of "smarts" to make that turn ? What IF I just connect 3 phase 200V (after transformer) to it will it run full speed or blow up ?
That would be a starting point to know that ! Don't care about encoder or feedback. These things are made so well it seems a shame to dump them .

Any ideas, advice? Has anyone achieved what I'm talking about here ? I have a little knowledge of PWM, Arduino, I can read simple circuits.
I mean simple .. remember Elon said the best part is no part after all we are turning a motor how hard could it be ?

[Al_The_Man]

Fanuc use a proprietary method of commutation on redcap motors, I have fitted off the shelf standard encoders to them which include a commutation track.
But its a bit of an effort.
I ran them with A-M-C BLDC drives together with Galil system.
Many of the Fanuc spindle motors are standard 3ph AC Induction motors, so a VFD will run them.
See post #4
https://www.cnczone.com/forums/servo...-software.html

[joeavaerage]

Hi,
it rather depends on how risk averse you are.

As Al has said the redcap Fanuc's require modification before you can use them. Al has long experience at doing such things, if you don't have that experience there is a higher probability
that you'll not succeed. If you spent $100....only to find you can't get it to work....well you might say 'it was worth a try' and walk away. But if you spend $200, or $400 then it becomes a bit harder
to walk away.

As far as I'm concerned the more money I part with for a particular piece of equipment, or as in your case an experimental attempt to resurrect a piece of equipment, the more my demand that
I get a credible and working result. The more the money....the greater certainty I look for. Its just how I am.

Consequently I can and do experiment with various ideas.....if the cost is low. For example I bought a 3kW servo a few years back, a remanufactured AC servo from cicra mid 90's. It has a resolver
rather than an encoder. I paid about $260USD (including shipping to New Zealand). In the years since I have experimented with it and am designing, building and programming my own servo drive.
The parts for the servo drive have cost about $150USD to date. Its been a great learning curve, and has not been overly costly, at least over the years that the project has been running. If it had cost
$1000 then I would all but require a result, and the prospect of taking on an experiment of that value does not appeal.

You have to decide what sort of time and money you want to invest in the idea and weigh the probability that it may be in vain.

Craig

[joeavaerage]

Hi,
one of the first experiments that I did with the servo I mentioned above was to try to drive it with a VFD. It worked, after a fashion. It had a very limited speed
range where it worked OK, about 10:1. Also when the load came on to the motor it would slow and eventually start to pole slip. It did this at a very much lower torque than
you'd expect from a servo of this size. Its rated at 12Nm, and 48Nm overload, but under VFD control was capable of about 6Nm only.

All-in-all I would call the experiment a failure, but on the other hand it was very instructive to me. AC servos are meant for, and only perform at their best, as synchronous motors.
VFD's are designed for asynchronous motors, and do poorly when attached to a synchronous motor. This was an important learning event for me. As I already had the VFD and it cost nothing
but my time to do the experiment....and somewhat longer to digest the results. I should consider the experiment a success. I learnt plenty without having to spend hard earned cash.

It did then present the idea that I'd have to design and build my own servo drive for it. I had a working example using Field Oriented Control running in speed mode only about six years ago.
It worked well, I had it running to 4500-5000rpm (cf 4000rpm rated), and about 10Nm-15Nm continuous torque. The whole lot was pretty 'Heath Robison' and not it any fit condition to be put into
my mill...but it was a good start. Since then I've changed my job, sold my house and shifted to a different district, bought a business and built a new CNC mill......and so on.
I have finished my trunnion fifth axis which has absorbed a great deal of time and even more money.....so my servo drive project is looking like I might resume it....after a six year break!

Craig

[Jim Dawson]

Over the years I have junked several cnc machines due to lack of room , too big ,too heavy , whatever the reason. I have saved parts such as servo motors , spindle motors, etc.

Spindle Motor!
How about a 8000 rpm (max) fanuc 200V spindle motor do I need a lot of "smarts" to make that turn ? What IF I just connect 3 phase 200V (after transformer) to it will it run full speed or blow up ?

I can answer this one, having done it. I ran my lathe spindle with the same motor and a VFD for a few years until I upgraded to a servo motor. I just bought a sensorless vector capable VFD of proper HP(kW) rating. Set the parameters and pressed go. Never had a problem. That motor is just a special wound induction motor, so is perfectly happy running on a VFD, speed control was very good even with no feedback.

I used an Automation Direct GS3 VFD at the time, but there are a lot of equivalent or better drives available today.