TOS-KURIM CNC Upgrade

[Muzzer]

One of the windings is across 1 and 2 - it's the winding at the top of the RH photo. The other winding is between 3 and 4 and is wound on the bottom of the photo. They are connected in series, so that you end up with double the voltage of each winding, from end to end. The centre of the combined winding is grounded. You could remove that unless you want your system voltage hard connected at its midpoint - at least this way the DC is at a known potential.

Looks as if you have both 380Vac and 415Vac primary taps.

If you are going to use a 415Vac connection, the primary would be connected across any 2 of the 3 phases of the 415Vac mains. However, if you were to connect it across single phase 240Vac, you'd get proportionally less output voltage. That might actually be handy here.

If you had 2 x 140Vac connected in series and full wave rectified them, you'd end up with 1.414 x 280Vac, which would be almost 400Vdc. You probably don't want that! If those really are 140Vac each, your original rectifier must have been half wave rectifying the outputs with the 0V at the grounded centre tap, so that each winding only conducted half of the time, giving a final DC voltage of around 200Vdc.

If you were to connect up the 380Vac primary tap to single phase 240Vac you'd get 88-0-88 Vac, which would get you about 125Vdc if you used half wave rectification. That would be a simple solution if you don't mind a slightly lower max speed. Probably wouldn't be an issue really.

If you want to get closer to 140Vdc output with 380Vac or 415Vac input, yes you'd want to be seeing 100Vac on each winding and connect it up as it was originally ie half wave rectification. One diode on the end of each winding, each pointing to the electrolytic cap, with the "0V" cap negative taken from the centre tap. To do that, you'd need to cut the big black wires on the outside of the windings and remove equal turns from each until the output is 100Vac. That's about 30% of the wire.

Do you have either a schematic or a photo of the capacitor and rectifier(s)?

[JimJam]

If you were to connect up the 380Vac primary tap to single phase 240Vac you'd get 88-0-88 Vac, which would get you about 125Vdc if you used half wave rectification. That would be a simple solution if you don't mind a slightly lower max speed. Probably wouldn't be an issue really.


Do you have either a schematic or a photo of the capacitor and rectifier(s)?

This would probably be a sensible solution a least for now to get the system running.
That was going to be my next plea for help, I can't confidently say I have located the capacitors and rectifiers! I have attached a load of photos of the internals, if you wouldn't mind casting your expert eye over them that would be much appreciated.