TOS-KURIM CNC Upgrade

[Muzzer]

Hmm, that seems to be a set of 3 SCR phase angle controllers rather than "normal" (to us) DC servo drives. These run from ac, so you can look and you can look but you won't find any big electrolytic caps anywhere. The 3 axis drives are those power modules in the 4th photo. You can see there are 6 of them in the 3rd photo. The drivers for the SCRs are in the 2nd photo. The date codes on the compts suggest the boards were built in 1980, so it's an old beast. Technically, they operate at 50Hz, rather than several kHz and vary the duty cycle to modulate the motor current / torque.

Bottom line is that there is no electrolytic cap(s) and the rectification is actually done by the SCRs (thyristors) and the SCRs are commutated (turned off) by the alternating voltage. The supply voltage is indeed two lots of 140V - but ac not dc. The labels on the axis / SCR controllers mention "2x140V", or 280Vac centre tapped in fact.

I think you can safely bin all the contents of the cabinet, as there is almost nothing you can reuse. Even the mains transformer is of questionable value to you. If I were you, I'd want to run the whole thing from 240Vac single phase and keep away from 415V, as there's really no benefit. You need 100Vac on the secondary, a simple bridge rectifier (600V) and an electrolytic cap rated at around 200Vdc.

The servo motors look like good machines and are indeed DC brushed motors. As I said earlier, you can get rid of the tachos and replace them with simple encoders. Indramat is nowadays part of Bosch Rexroth etc, so these drives and motors were probably designed like brick shithouses.

I'm not certain what those 3 transformer-like things are. They are labelled "Drossel" which means something like "choke", so probably line inductors to filter out the current lumps and improve the mains current waveform / power factor. Again, almost certainly of little or no value to you.

[JimJam]

You certainly know your stuff when it comes to this! Everything I have found dated suggests it was built in the 80s (1983 was the latest date I found) so its certainly not cutting edge technology in there!! I'm glad you said to bin it all, I'm sick of the sight of the inside of that cabinet!!

I'll have a play with the transformer today, if I don't get anywhere I'll look into something a bit more suitable..

so if I went single phase and got the 100Vac, would these do to get the DC:

https://cpc.farnell.com/multicomp-pr...ule/dp/SC15622

https://cpc.farnell.com/panasonic/ec...dc%20capacitor

If single phase is the best option, would you completely get rid of the 415V and us a VFD to power the Spindle motor? or Could I still use the 3 phase supply with a relay or something to switch spindle power on from the controller? I know the controller module I bought shows a VFD on the wiring diagram so that may have to be the way to go anyway..

[Muzzer]

Yes, that's the right kind of voltage and current for the diode bridge - and CPC is a good place to buy stuff. A lot of their stuff is identical to Farnell (sister company) but inexplicably sometimes a lot cheaper. You need to bolt it to some form of heatsink but unless you plan to push the spindle to its limit and keep it there for hours, it won't need much. I just fastened mine to the steel backplate and it's been fine. I have something similar on mine which I scavenged from the original VFD in my 1983 Shizuoka.

I think I mentioned earlier that I repurposed a 110V site transformer for my machine. If you are feeling flush / tight for space, that's an option. https://www.screwfix.com/p/carroll-m...mer-110v/43658

Here's my transformer / rectumfrier / VFD installation. The relay next to the rectumfrier is a time delay jobby to allow the caps to charge over a second or two. The caps themselves are hidden behind my Centroid Acorn board further down.


For the caps, I used a couple of these in parallel https://cpc.farnell.com/vishay/mal21...P=TREML007-005. You could probably get away with one if money is tight.

That cap you linked to is FAR too small. It needs to be about the size of a coke can, speaking technically.

Here's my cabinet. No, it's not a textbook example of cabinet installations but it works.

Doesn't seem to matter what I do here, I can't get the photo orientation right. What's the trick? It seems to be using the iPhone metadata to determine the orientation.