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[gord5147]

Hi I am considering a 3 axis mill using 85 vdc servo motor with 2000 line encoders which I already have I also have the dc power supply I am sure that acorn is the board for me,the drivers I am starting to favor is the machdrives BRC 150v but I cannot find any posts on this forum is there anyone out there using these if so could you provide any comments good or bad any any help with wiring schematics would be a great help thanks.


Any UK users could also advise as to purchase of acorn as to weather US or EU route gives best deal on cost & duty payments.

I am sure when I start will be back with lots more questions to this great forum

Gordon

[Chaz]

Hi I am considering a 3 axis mill using 85 vdc servo motor with 2000 line encoders which I already have I also have the dc power supply I am sure that acorn is the board for me,the drivers I am starting to favor is the machdrives BRC 150v but I cannot find any posts on this forum is there anyone out there using these if so could you provide any comments good or bad any any help with wiring schematics would be a great help thanks.


Any UK users could also advise as to purchase of acorn as to weather US or EU route gives best deal on cost & duty payments.

I am sure when I start will be back with lots more questions to this great forum

Gordon

Hi Gordon,

Ive done two machines already with Acorn (well, 2nd one is ongoing at the moment).

The servos need to be able to take step / direction. If you can only use -10V to 10V, then you need something like the CS Labs IP-A.

Schematics on the website, just search for them, they show a number of options.

In terms of UK, shipment takes 2-3 days and you will pay duty. I think I paid £120 for the last one but that included the MPG.

[Commotion]

With my recent lathe project I decided to try reuse the original dc motors. I tried using leadshine dc drive because I had good success with their ac drives in a mill project. I have had issues with drive faults but am thinking it’s the encoders so I have ordered amt102v encoders. When looking for encoders I was searching drive options in case the new encoders don’t fix the drive faults and recently came across the machdrives dc servo controller. They looked pretty good and a bit cheaper than the gecko g320x. I have not used them so have no actual feedback but they say they are an Australian made item which is a plus for me. I just don’t know what the warranty or support is like as apparently that’s where gecko is very strong.

The acorn board in my opinion is very good. I now have 2 machines with the acorn functioning and I like the interface and the usability. I have had a couple hurdles when getting them up and running but usually it’s somethjng silly I had done wrong and all the info to get it working was found here with the help of the forum members.

[martyscncgarage]

Hi I am considering a 3 axis mill using 85 vdc servo motor with 2000 line encoders which I already have I also have the dc power supply I am sure that acorn is the board for me,the drivers I am starting to favor is the machdrives BRC 150v but I cannot find any posts on this forum is there anyone out there using these if so could you provide any comments good or bad any any help with wiring schematics would be a great help thanks.


Any UK users could also advise as to purchase of acorn as to weather US or EU route gives best deal on cost & duty payments.

I am sure when I start will be back with lots more questions to this great forum

Gordon

Post pictures of the mill.
Is it a standard size Bridgeport mill?
Always post pictures of the machine, the motors/drives and control cabinet.
Exactly what is the voltage COMING OUT OF THE POWER SUPPLY after rectification? Are you just reading the motor lable fo 85VDC? That doesn't mean its being fed with that high voltage. Can make a difference which drive you buy.

If you are hellbent on putting yourself through trying to integrate DC brush servos, be forewarned its not trivial, you generally need to upgrade the encoders, then fight with getting them tuned to the drive.
I would recommend these drives from www.cnc4pc.com:
80VDC 20A: https://cnc4pc.com/dg4s-08020-dc-servo-drive.html
160VDC 35A: https://cnc4pc.com/dg4s-16035-dc-servo-drive.html

For lower voltage DC Drives, Geckodrive G320X is also a very good choice:
https://www.geckodrive.com/g320x-digita ... drive.html


CNCDrive has been around awhile and is established. CNC4PC.COM has also been around a long time and tries to provide very good customer service.

Again, if we could "SEE" what you are working with, some better suggestions could be made.
Marty

[gord5147]

Thanks for your input Marty.
The machine i am using is a late 80s kmb1x hurco knee mill this was built as a cnc so has .200 pitch ball screws on all axis,built in screw/slide lub system & a 3hp manual adjustable spindle motor the machine is in first class condition but with a dead control,when i got it it cam with 3 new old stock electrocraft servos these have tachs but the brushes have been removed they also have litton 200 line encoders these are single ended with a marker pulse 5vdc,the power for the servos comes from a transformer with a 60vac output via a centroid dc bridge/cap giving 85vdc all these parts are so good it seems a shame not to use them.
As regards the drives I have looked at the cnc drive units but here in the uk having to import drives & acorn puts a import duty in place when I found the machdrives they seem a very good product at a worldwide delivered price which is hard to beat it is well worth looking at there website.
They have told me that many acorn customers use there drives, strange that i can not find ref on this forum & have no replies from anyone?
At this time I have not ripped out all the old electronics as until I have firmed up my list of components I feel it is the best way to go but I do know Acorn is the route & not Mach as was my first way of thinking.

Any help on the Acorn/machdrives Brc route will be great.


Gordon

[cnckeith]

gordon, reusing these old dc servos is fraught with time and money wasting pitfalls....sell those dc motors on ebay and pick up some new AC brushless servos like the Estun 750 watt that we sell and you will be turning motors with acorn in an afternoon and be making parts with the machine rather than working on it. )

[martyscncgarage]

Can't agree more with Keith's statement. Buy once, cry once.

Marty

[Chaz]

Agreed, I went AC Servo, considered the DC motors but too many things that can go wrong.

[Muzzer]

I'm in the UK and bought my Acorn from the dealer in Denmark, which shipped fast and without having to pay duty and vat (and handling!).

http://makersupplies.dk/search?controll ... t_search=
I also have brushed DC servos and simply changed to the CNCdrives servo drivers which take step and dir. You need the motor encoder but can jettison the tacho which isn't needed on modern digital drives. Work fine, the setup software was easy to configure and they haven't given any problems. They are based in Hungary.

https://www.cncdrive.com/DG4S_16035.html

Murray in Lancashire

[gord5147]

Hi Murray thanks for your replay nice to hear from someone using brushed dc motors the comments made by all the others re ac motors are noted & I know the advantages of using them my motors are to good not to use,I have been running a similar machine for the last 10 years with 100% success.

I am still looking for anybody who has used the acorn board with machdrives BRC drives from Australia there must be someone in the world come on guys? comments please.

The reason I am so keen on the machdrives I that over here in UK all parts I need will have to be imported with shipping/duty costs being high also the cost of the 3off DG4S-1635 drives being £451.85 ($578.28) + duty but the BRC drives would only be £246.84 ($315.84) a large saving.
If these drives are as good as they say they are there sales must increase, it seems strange there is no feed back from anyone?

I am sorry if I seem to be proceeding with caution as I need to make sure that all the parts I order will talk to each other.

This is a great forum but do sometimes feel a little isolated here in the UK any help appreciated many thanks.

Gordon.