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Graziano Sag 12S Stopped Working

spectre1995

Plastic
Joined
Jul 29, 2017
Hello all,

We have a Graziano Sag 12S at the shop, and when shifting into the lower gears, the lathe suddenly shut off, and now we cannot get it to start back up. Pushing the power button does not turn on the main motor.

Is anyone familiar with these that can perhaps help us troubleshoot it and get it back into working order?


Thank you all in advance!
 
do you have an electrician on staff or access to one. The first thing to do is to check all the voltages at all the critical points. The SAG 125 has a fairly complicated electrical system, it will require some systematic troubleshooting to figure it out.


dee
;-D
 
Hello all,

We have a Graziano Sag 12S at the shop, and when shifting into the lower gears, the lathe suddenly shut off, and now we cannot get it to start back up. Pushing the power button does not turn on the main motor.

Is anyone familiar with these that can perhaps help us troubleshoot it and get it back into working order?


Thank you all in advance!

Lathe is Italian, but there is a French (or Walloon?) language website in France or Belgium that collects all sorts of info for (predominantly) European machine-tools.

Graziano SAG 12 & 12S

Tony at lathes.co.uk may have manuals as well.

And Google finds others, too.

Your issue being shifting related sounds like it might be some sort of damage-avoidance interlock gone wonky. Prolly find and repair that sort of thing even without a manual, if so.
 
The most common SAG 12 problem relates to the oil pressure sensor on the transmission, which is in series with all the control contacts that enable motor operation. In parallel with the oil sensor contacts there is a time delay relay that provides some time for oil pressure to build up without immediately cutting out. If the lathe keeps going when you temporarily shunt the oil pressure switch (2 wires going to lower right corner of transmission), then troubleshoot for one of these problems: clogged or weak oil pressure sensor, low oil pressure, defective time delay relay. If temporarily shunting the OP sensor has no effect, the next place to look is probably the joystick switch cluster, which sometimes develops shorts or opens due to aging wire insulation. The SAG 12 Manual is readily available in scanned pdf. Search for a link on this forum. SAG 12's have a reputation for complex wiring, but it is actually fairly simple when you break it down. The other really basic test to perform is a voltmeter check of the AC and DC control voltages, which should be around 24 VAC and 24 VDC, but you'll probably need a Schematic and/or some photos to figure out where to probe.
 
a couple possibilities

Hello all,

We have a Graziano Sag 12S at the shop, and when shifting into the lower gears, the lathe suddenly shut off, and now we cannot get it to start back up. Pushing the power button does not turn on the main motor.

Is anyone familiar with these that can perhaps help us troubleshoot it and get it back into working order?


Thank you all in advance!

I have stopped my Sag 12S a couple ways:

1)accidentally hit the emergency stop button on the right side of the control box on the carriage: see if you can pull it out, if so, then the machine will most likely run normally.

2)when changing spindle speeds by pushing the speed control buttons on the control panel, I have found if I just lay on the button to reach the end of the speed range, the machine can produce an over-travel stop. There is a proximity switch, and a limit switch, for the travel of the variable -pitch pulley, and it seems the momentum of the pulley can cause it to move too far, passing the proximity switch and then activating the limit switch. This will cause a shut down, and you will have to go through the emergency re-start procedure to get the machine started again. The manual has clear instructions for this, it's not hard. This fault isn't caused by a defective proximity switch, even after replacing mine the problem persisted, so just sneak up on the speed limit by intermittently pushing the speed control button as you are approaching the speed limit .

3)Also, I was tricked by the oil-sight gauge on the headstock, it looked full, but it was low, and caused a shut down. Just have to put a little oil in, and it is fine, then. I suppose the other gearboxes have the same protection from low oil levels, so check all the sight glasses carefully.

sincerely

bridgeport9x42
 








 
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