Graziano SAG12

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LIALLEGHENY
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Re: Graziano SAG12

Post by LIALLEGHENY » Wed Nov 20, 2019 10:00 pm

1st picture, bottom left I believe is the rectifier.

Nyle

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Re: Graziano SAG12

Post by Harold_V » Thu Nov 21, 2019 2:29 am

Bill Shields wrote:
Wed Nov 20, 2019 4:49 pm
parts were available in italy last time i was tagging along with a friend (5 years ago)
Interesting, to say the least. Any idea of the source, Bill?

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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Re: Graziano SAG12

Post by Harold_V » Thu Nov 21, 2019 2:45 am

Tld2375 wrote:
Wed Nov 20, 2019 8:57 pm
If you look closely at the pics the burning on the transformer is obvious.
I'd highly recommend you explore the value of the fuse used in the clutch circuit. It should be something less than 7 amps, a fractional value included. If it has been replaced with a higher value, or if you had any issues with any of the speeds, or forward or reverse, you may know why the transformer is toast.

The control circuit relies on a given resistance of the clutches. If they short internally, as mine has done, you blow a fuse. If you replace it with a higher value, the machine may operate without blowing the fuse, but it will then draw too much amperage, which likely fried your transformer.
I don't know the difference between the contractors and the clutch solenoids. (yet)
There's three contactors, one for high speed, one for low speed, and one for the coolant pump. The clutches do NOT have contactors. They are operated by the joy stick. When you rotate the stick, contacts on the rather complex switch that's enclosed in the housing make or break, selecting the proper speed. There's a pair of micro-switches located in the pivot of the joy stick, which select forward or reverse. The push button on the end of the joy stick activates the opposite rotation direction, using the electro-magnetic clutches as a brake. The clutches are multi-disc type and are under constant oil bath. They appear to be bullet proof so long as the coil doesn't short. The coil is known to be troublesome.
I'll try to find some time to get deeper into this, this weekend, I would like to get this thing working again, its a nice machine. However it the cost/time and complexity get to much I'll consider the sell option (Harold)
I have another lathe.
I thank you for keeping me in mind. I have only the Graziano, and I am not in the position to invest in another machine. I've owned mine since 1967, and used it for gain for 16 years. It has been very reliable, with only three clutches and the selenium rectifier failing. The only other troublesome thing I've experienced is the spindle turning on without activating the joy stick. I learned that the micro switch contacts slowly erode, depositing a conductive film inside the micro-switch. When that happens, it conducts enough to activate the forward clutch (It's never happened with the reverse clutch). One hopes that it doesn't happen when one is using a chuck wrench. That would certainly not be a good thing, nor would it be good if one was taking a measurement with a micrometer. I've formed the habit of putting mine in neutral when working with the stopped spindle. Solution is to replace the micro-switch, which is also difficult to obtain, as they made a change in the height, so newer switches won't fit in the crowded housing.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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liveaboard
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Re: Graziano SAG12

Post by liveaboard » Thu Nov 21, 2019 3:22 am

I just saw a Graziano sag 14 for sale near me ; $8,000.

If I were a rich man, I'd be on my way to have a look...

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Bill Shields
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Re: Graziano SAG12

Post by Bill Shields » Thu Nov 21, 2019 7:22 am

It was someone in the Milan, Italy area where our company offices are (were) located.

They are out there; https://www.machinio.com/graziano/lathes?page=3#results
Too many things going on to bother listing them.

Tld2375
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Re: Graziano SAG12

Post by Tld2375 » Thu Nov 21, 2019 1:16 pm

This is all great info! Thanks everyone!
The interesting thing about this is, there never was any indication of anything going wrong. Everything worked perfectly until one day it didn’t. I’ve owned this machine for 25 years and its been rock solid. The fuses are the same ones in it when l got it. The thing in the lower right that someone said looks like a rectifier is actually a fuse holder.
It appears that it might have been added at some point before my ownership began.
The three fuses on the left are good and the single one on the right(missing in the pic) has blown. So l guess that one (3amp) is for the control circuit. Does anyone know how much current the control circuit should Draw? I have a power supply that could be wired in to test it, but it would be helpful if l knew how much current is normal.

Patio
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Re: Graziano SAG12

Post by Patio » Thu Nov 21, 2019 4:09 pm

I can only take a guess at it. The control circuit runs the start contactors, maybe a couple of relays and the indicator lights. I would think it should be under 10A and 3A might be right. The idea of connecting a remote power supply for testing, I think is a good one. It will tell you if there is a short in the system and allow you to actuate all the different contactors and relays.
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Re: Graziano SAG12

Post by spro » Thu Nov 21, 2019 4:54 pm

I think it is good too. I was thinking something else though; being quite familiar with the "solderless connecters " of those times, recalling that I had to come around and solder many of them. When soldering for a solid connection, the sleeve melts. I see no evidence of that in this large array. A single crimp doesn't do it over time of vibrations. Heck but doesn't voltage increase when there is resistance at the same current?.
There are all types of IR or wireless detectors for heat. I think they measure other things now and may be a good troubleshooting tool.

spro
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Re: Graziano SAG12

Post by spro » Thu Nov 21, 2019 7:00 pm

Since I have no experience with a Graziano SAG12, it is like telling the owner of a Ferrari that one tire is low. I just bought a non -contact thermometer gun on eBay because of its description. It supposedly has an adjustable focal range which goes close enough to detect heat of individual electric components and that would be connections too, if it isn't all hype.

Tld2375
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Re: Graziano SAG12

Post by Tld2375 » Thu Nov 21, 2019 9:06 pm

Lyle, you are correct the rectifier is in the first pic, bottom left. I can look right at something and not see it!
This thing is starting to make sense now. I did find some rating plates on different parts, but they are on the bottom of the contactors. The transformer has one also, but it needs to be removed to see it...
Maybe next weekend l can dig in. If you see smoke southwest of Portland...

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tornitore45
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Re: Graziano SAG12

Post by tornitore45 » Fri Nov 22, 2019 4:14 pm

If everything fail you can take the transformer to a motor rewind shop and see if they can reverse engineer the transformer.
Is not difficult, I have done a few. It would be a sin to junk a good late for a transformer.

One thing to consider: A roasting transformer put out an unmistakable smell just before failing completely.
If it is not the transformer the next thing to look at is the rectifier. It can be tested but it will be so simple to replace with modern devices.

I do not have the time to dissect the schematic but is clear that the primary is off 2 Phase 220V probably 208 in the US
One winding is Full Bridge rectified - low voltage - probably 24V for the contactors coils and one winding I can't figure without flattening the schematic.

Flattening a schematic means making it immediately readable like the original designer made it before the knucklehead in the publication department though it would be so nice to rearrange all the component to reflect the Physical position adding a 50 miles of wire that give you headache to follow and guarantee to miss.
Mauro Gaetano
in Austin TX

Patio
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Re: Graziano SAG12

Post by Patio » Fri Nov 22, 2019 8:36 pm

What am I missing? I don't see a rectifier on the 24V control circuit. I thought it was 24VAC. I do see the rectifier on the 30/32 volt clutch circuit.
Live for the moment!
Prepare for tomorrow!
Forgive the past!

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