Graziano lathe and rotary phase converter

[pete]

Ago, I know just about nothing about electrical and the same for your lathe. And possibly you already know about it, but there's a very long thread over on the Practical Machinist site on the Schaublin, Cazeneuve, Weiler, Graziano, Mori Seki sub forum titled SAG 12 restoration progress started by a guy called Texas Turnado. There's a large amount of electrical information later on in that thread and your answers are I'd bet right there. Right now it's on the first page and 7th thread from the top.

A bit OT, but that thread shows what I think rebuilding a lathe really means. The poster was extremely talented who unfortunately died pretty much when he got that lathe completed. His reboring of the tailstock and then building a new tailstock barrel is more than worth reading for anyone interested in machine rebuilding or high accuracy lathe work at any time.

[hammermill]

https://www.google.com/search?q=Grazian ... ITrQU-M%3A

here is the start of looking for prints. it does look like the transformer feeds a full wave bridge which then feeds the controls

[ago]

I removed the contactor from the machine and applied 24VAC from a independent power supply. It snapped in instantly. Then I took the same power supply and put it thru a full wave bridge rectifier 24 VDC and same thing snapped in correctly. One of the first things I did before all this separate power supply attempts, was to clean the contacts and even switched the contactor with the coolant pump. To no work. So the contactors when I apply different power supply works perfect. I believe the original power supply is subject.

[hammermill]

if you have one of the large metal finned rectifiers, selenium, its proably bad, replace with a new 50v 20 amp full wave bridge or one of the power supplys we talked about.

[ago]

Hammermill,

Thanks again for info, I ordered a 24VDC 20amp power supply and going to rewire and simplify the lathe.
Dave.

PS. If you pm your e-mail I will send you the wiring diagram. I not to computer savvy to down load on this site.

[ago]

Replaced the silenium rectifier with a 50v 20 amp full bridge , no work.

[hammermill]

drat does it now apear dead or still chatter???

it may be a foregone but the$$ sideways is for the two ac connections and are fed from the transformer(now at likely suspect status)
+ = positive - + negative for dc output

[spro]

Sometimes we have to break things down into subsets in order to eliminate possibilities. I don't trust anything. Eliminate one section or another and see if it works. You may find it well to disconnect the controller, know how it works and substitute an insulated switch to work the contactors. Same fuses, low voltage at the switch.

[shootnride]

So the contactors when I apply different power supply works perfect. I believe the original power supply is subject.

ago,

If you are applying power with the "different" power supply at exactly the same location where the old power supply is connected in the circuit, then it certainly sounds like a bad power supply. If you are making the connection at a different point in the circuit, you could possibly be bypassing another component that is causing the problem. Maybe the old power supply has degraded over time or as I believe Harold eluded to, maybe those power supply's were marginal when new.

Ted

[ago]

Update on SAG 12. My motor contactor chattered wouldn't stay engaged, Smoked the Silenium rectifier. I upgraded my RPC with a Phase Craft 7.5 panel. Replaced the silenium rectifier with a full wave bridge rectifier (50 amps 1000 volts). I kept the original wiring timer oil pressure switch etc. The lathe now works as intended. Sid Far a electrician ,electronics man figured the problem and helped me along.

[JackF]

AGO, glad the problem is solved. This has been an interesting thread.


Jack.