Okuma Servo Drives

That does seem excessive now that you mention it. I have asked Diederik to check.

This is quite a big machine though. Spindle is 30kw.

Henk

From what I recall from mine, the Z motor plate was marked about 15A and the original servo drives were really for a high value (50 or 75A)

I used a servo drive that was able to output up to 18A (peek, short burst), but the final performance was limited, that made me think that the peek amperage of the servos was indeed large, and that the value present on the plate of the motor was for constant amperage value.

Thanks.
I think that is the case here as well. the 50A and 100A on the drive plate is actually the max continuous current of the IGBT module used on the drive,but i doubt the motor can do that continuously.

I have used 8i20 drives on 2.8kw motors before and icould not get them to perform as it used to with the original drives. I think it was because the max current is limeted to 30A. they are rated 2.2kw max for a reason....

I found a version of STMBL on github called Ottercontrol. Max current is 50A and peak of 90. Problem is max voltage is low...60v or so. Any idea if this can be upgraded to say 400v?

Henk

X axis:
1.8 kW
131V
1200rpm
9.3A
6 pole
146 kg-cm -160 kg-cm

Z axis:
4kW
2000rpm
159V
15.7A
6 pole
195 kg-cm
220 kg-cm stall

Turret:
4.3kW
140 kg-cm
154 kg-cm stall
3000rpm
160V
16.8A
6 pole

So from the information of the motors, if you had to give a honest opinion, what would be the best way forward? I am thinking to also look at advanced motion control drives?
with regards to the STMBL drives, Can I possibly buy one allready built? For me to test it out? It seems like a nice project to built, but will require a lot of my time, which is a problem.
I prefer not to get too involved with electronic building projects, as I already have a lot of mechanical, electrical and retrofitting work waiting for me, so to get involved in electronic manufacturing as well, will put me behind further in my work.
Or maybe someone has a spare one that I can buy off them to test?
My thinking is to test it, if it works, and I am happy, then I will make 10 or 20 at a time, which will make it worth it. This might defeat the whole drive behind open source? Sorry...

Hi Andy
See attached.

I have not worked with resolvers or serial encoders so not quite sure what I'm looking at here.

Thanks for your help.

Thanks Henk and Andy for your interest. Much appreciated.

Normally if it is a absolute encoder, there would be a battery pack somewhere along where the encoder plugs in, but I can't find one, unless it is hidden.
Not sure if type fc position encoder is just a product of okuma, or if it has a universal meaning.
Allthough, there is data pins... so I assume this is absolute encoders. Now: Encoders is easily available for relatively cheap, so if I can just replace the existing encoder with a normal incremental differential encoder with signals: A, A-, 0V, B, B-, 5V, Z, Z-,... I am keen to do that. Will that make things simpler? I once used a normal 4 pole electric motor with a vsd, and a encoder, A worm gearbox, with a 7i77 to control a Z axis of a gun drill, and it is still in production today, and is working well, and was sufficient for what was needed. Now, if I can just get a velocity controller for these motors, that will make me happy. I don't really want to spend too much time figuring out how these serial encoders etc. works. I like to keep things standard and simple. So... that said... would you reccomend I use a stmbl drive in velocity control mode? and then handle the position loop within linuxcnc?

Andy, Just to verify: the signals on the existing encoder is:
1. FG(I assume this is ground)
2. SIN
3. SIN-COM
4. FG
5. COS
6. COS-COM
7. FG
8. MPR
9. MPR-COM
10. DATA
11. DATA-N
12. E-CLOCK
13. E-CLOCK-N
14. WRST
15. WRST-N
16. +12VC
17. OVC
18. -12VC
19. 0VC

looks like a normal sin/cos encoder, with additional abspos, and possibly multiturn.
stmbl can use sin/cos encoders only, but requires autophasing on startup.
I have seen many encoder pinouts, but yours doesnt ring a bell.
if you have the original drives, why not reuse them?
or use them to figure out how the serial data works?

Rene