Thread: SAG 12 Restoration Progress

If i hook up the wires together and take a resistance reading and they read all the same between phases I should be ok to try it?

If i hook up the wires together and take a resistance reading and they read all the same between phases I should be ok to try it...

Not really - you will be measuring a very low resistance (two windings in parallel with two paralleled windings in series with each other and in parallel with the first two windings. If you want to make resistance measurements, measure each winding by itself (1 to 2, 3 to 4, ..... 11 to 12) - these should all be very close to the same resistance. Also measure these windings to the frame - there should be an open circuit to the frame for each winding. If any of the windings give a low ohms indication to the frame, then there is a short to the frame, the motor is bad, and will need to be rewound or replaced.

Today I finished mounting the knobs, installed the control panel, and wired it up:



I decided to use .25 in wide push on terminals and terminal block for these, instead of the little setscrew blocks Graziano used back in the 70's:



Since there are three wires meeting at this point (one to the control panel, one to the joystick, and one to the electric transmission), I used "piggy back" terminals for one of the sets of wires. These have a male terminal on the side of the female terminal so another female push on can be attached to the same point.

The terminal block is shown pulled out of the access slot at the back of the gearbox, but will be pushed back in and attached to the casting for support and to prevent possible shorts to the base casting. This makes it much easier to attach and detach wires compared to the original arrangement, which required crimping two wires into one terminal, and then attaching to the setscrew block.

As shown, there are seven wires, one for each of the six clutches and one for the clutch supply voltage, which is supplied on pin 9 of the control panel, and goes to the joystick (but not the transmission).

Since I am using a VFD, it will be wired directly to the motor, and the pushbuttons at the top of the panel will be wired into the VFD so they control it. I am not planning to use the coolant pump anytime soon (if ever....), so I only need to wire single phase to the control panel terminals that end up feeding the transformer. If I ever do use the coolant pump, I will probably wire in a small VFD for that motor.

If anyone knows where to get the small slip-on wire markers with numbers 0-9 like those shown, I would like to hear about it....

I hooked up motor to my Vfd and it worked perfectly with the wiring sequence you suggested. This was going on too long. Was just about going to buy another motor but held out and it payed off as retrofitting a different motor would be a pain. Now I can finish her up and order a tool post, chuck and a larger Vfd. Thanks so much for your help.

Originally Posted by 2rods

I hooked up motor to my Vfd and it worked perfectly with the wiring sequence you suggested. This was going on too long. Was just about going to buy another motor but held out and it payed off as retrofitting a different motor would be a pain. Now I can finish her up and order a tool post, chuck and a larger Vfd. Thanks so much for your help.

Glad to hear it worked out for you - that is a metric flange motor and a replacement would be difficult to find here in the states (but common in Europe and probably Asia). I once looked for a metric flanged motor for a vertical mill, and they can be found - but sure not common, and not cheap. That's why a lot of folks have them rewound.....

Retrofitting a US motor would indeed be messy, as both shaft and flange would require attention....

And thanks for coming back and letting me know the outcome.

One thing that's puzzling is the output amps of vfd when motor running without belts and any load is around 9 amps. The max of Vfd is 7.5 amps. I even turned the electronic overload protection down to 50% and I still didn't get ant overload fault. The input draw on each leg is about 1.5 amps. Does this sound right or is something wrong?

Originally Posted by 2rods

One thing that's puzzling is the output amps of vfd when motor running without belts and any load is around 9 amps. The max of Vfd is 7.5 amps. I even turned the electronic overload protection down to 50% and I still didn't get ant overload fault. The input draw on each leg is about 1.5 amps. Does this sound right or is something wrong?

How are you measuring amps? Most external meters are notoriously inaccurate due to the totally non-sinusoidal nature of the VFD output and/or the transients present. Now, if you are talking about the motor current as measured and displayed by the VFD, then something is fishy - but I am guessing that is not the case. You should have an option to display current built into the menus of the VFD - what does this read?

Also, are you quoting single phase input current or phase currents of each phase? Single phase current must be higher as power is conserved (phase relationship must be taken into account for three phase power).

Measuring with a clamp on meter. I have a teco FM50 and I don't think it will display current. The single phase current is about 1.5 amps and the 3 phase current with the clamp on meter of each leg is around 9 amps.

Originally Posted by 2rods

Measuring with a clamp on meter. I have a teco FM50 and I don't think it will display current. The single phase current is about 1.5 amps and the 3 phase current with the clamp on meter of each leg is around 9 amps.

Totally bogus readings for the phase currents (probably reading peaks of a totally non-sinusoidal waveform) - meters like that are calibrated to read correctly assuming the current is sinusoidal. Also impossible from a power standpoint - how can the current in each of three phases be higher than the input current at single phase? Are these the readings for rated speed of the motor (60Hz)?

What does the VFD say the phase currents are? What is the nameplate current at 240V?

Yes reading at 60 hz. The Vfd won't display current or I can't figure out how. The name plate current @220 v is 16.8 amps. This is a 6 HP motor I believe. If I put the Vfd on the 2 HP motor that it belongs on both in and out currents are around 1.5 amps iirc.

Originally Posted by TexasTurnado

Does he have the box for the saddle also? We need a diagram of what's in there to see if it works with the connection points on the diagrams we already have.... I suppose, worst case, I could draw something to work from scratch but it would be easier to start with what's already there. Try to get that stuff back before he skips town....

I have the long covers and will probably just make the short ones up near the chuck...

He has it - or the top surface with the knobs and switches at least. Made a bit of an effort the other day to clean the congealed coolant/way oil off some of the wiring tags. Definitely been some rough buggers wiring in the past, with utter confusion of different numbers from one end of a wire to the other and almost certainly, swapping harnesses too.....joy! Managed to find the feed bar clutch at last, it powers up and works.

Oh, not an exhaustive search by any means, but slip on numbers seem a bit passé at the electrical outlets here when I asked a little while back, it seems clip on after crimping the terminal seems to be the new method.

Originally Posted by BillE

He has it - or the top surface with the knobs and switches at least. Made a bit of an effort the other day to clean the congealed coolant/way oil off some of the wiring tags. Definitely been some rough buggers wiring in the past, with utter confusion of different numbers from one end of a wire to the other and almost certainly, swapping harnesses too.....joy! Managed to find the feed bar clutch at last, it powers up and works.

That's great - I would like to see what's there when you have it and a chance to send it this way.

Originally Posted by BillE

Oh, not an exhaustive search by any means, but slip on numbers seem a bit passé at the electrical outlets here when I asked a little while back, it seems clip on after crimping the terminal seems to be the new method.

I found some of the slip on kind on ebay, but they were too big for my wires' size - I may end up using the self adhesive kind you wrap around the wire. And I did find two sets of 1 to 6 on the old wire I had to cut off during disassembly due to two wires being crimped in one terminal for each of the six wires.


I had Ms Grazi running today - first time in two years - not anything like the final wiring, but I was able to test the transmission, gearbox, and headstock for proper operation, noise, etc. I have the lathe running from the original control panel, but the motor is wired separately to the VFD, and controlled from its front panel.

Some additional work has made itself known: Firstly, the VFD needs a braking resistor, as it trips out from time to time when shifting gears. The main problem ocurrs at higher speeds where it overvolts the DC bus on deceleration - so I won't be able to use this spare L200, as it does not have the FET's needed. I will probably switch out with the SJ 200 I have on the 12 in Atlas - it already has the braking resistor attached.

The other faults may be harder to fix: occasionally it will exceed the motor current set when shifting the transmission, so I may have to set that current higher - if too much higher, it may take a 5HP VFD to handle this 3HP motor. Tomorrow I plan to wire the motor to the SJ 200 and see if the problem persists.....

The other new work is to replace the forward microswitch in the joystick assembly - sometimes this one loses contact when it should not. At least the braking microswitches work as expected - they would be harder to replace as the space is more limited for them.

The transmission shifts as expected, but then I had already tested it alone and verified operation - OTOH, one or more of the clutch coils may give up at any time....

Overall, I am quite pleased, as the transmission is much quieter than it was before and the headstock is not bad at all, considering its age. I had what I thought was gear missing teeth noise to start with, but discovered I had not fully tightened the nylon lock nut on its shaft, causing it to rock back and forth a small amount during each revolution.... That one had me worried for a while....


For RivetsP: the switch you sent does not change state when the transmission is running - I know I have pressure, but not exactly how much. The guage I have has been over pressured and reads about 10 psi at rest. I will be willing to bet however, that the pressure is over 30psi at that point..... Did you test it previously for proper operation? I will probably see if I can locate a new one locally when I get to it.....

Originally Posted by TexasTurnado

I had what I thought was gear missing teeth noise to start with, but discovered I had not fully tightened the nylon lock nut on its shaft, causing it to rock back and forth a small amount during each revolution.... That one had me worried for a while....

This is the nyloc on the gearbox pulley not somewhere on the spindle? Did look a bit odd, but I'm used to seeing a bolt threaded into the end of the shaft on this.....loosened up without use of loctite as well.

Looking for a few replacement connectors for this orphan rail system today, as there's a few burnt ones - if you wanted to stay authentic to Weidmuller, noticed they do a range of connector and wire markers, which might match ye olde style.

To be honest I did not, I bought an extra brake line unit that was "working as removed" and being a brake line switch, I really can't say what PSI it switches at. Sorry about this, I know in a brake line it dosnt take much pressure at all to trip the brake light switch.

Can you take it off and attach a regulated air line to it, and see if/when it changes it's switch state? I have another one from the same model I can test here today.

Similar switches from brake lines can be found on alot of Kawasaki bikes, maybe 30psi is not enough though :? ? I would have thought that It would trip. An oil pressure switch comes to mind, but those typically have one contact pole, and use the engine block as a ground.

I'll test what I got here, and send let you know by the end of the day

Originally Posted by BillE

This is the nyloc on the gearbox pulley not somewhere on the spindle? Did look a bit odd, but I'm used to seeing a bolt threaded into the end of the shaft on this.....loosened up without use of loctite as well.

I have nylock nuts on both the transmission and headstock input shaft - it was the latter that was slightly loose. It is over 100°F here, so I was too lazy to go out and get the air hose, bring it in leaving the door somewhat open for the hose, so I could use the air impact tool to tighten it. Instead, I used a socket on a 24V battery operated drill to fighten it - result: not tight enough....

Originally Posted by BillE

Looking for a few replacement connectors for this orphan rail system today, as there's a few burnt ones - if you wanted to stay authentic to Weidmuller, noticed they do a range of connector and wire markers, which might match ye olde style.

I found their site and nosed around in it for a while, and found the terminal strips, but the markers are now expandable so they will fit a range of wires.... I saw some just like them on ebay, so I may order some to see if they will work.

Today, I connected the Hitachi SJ 200 with load resistor to the motor and still got trip outs due to overcurrent and overvolting the DC bus. This is a 3ph 5HP SJ 200 running on single phase, but it will let me adjust the current all the way to 22 amp with the 20% overlimit allowance. Bottom line, it still trips the SJ 200 set to 21 amp! I can see the display reach 14 amp when switching to the highest speed, with or without back gear engaged, but I'm sure it goes above 21 amp to trip the overcurrent limit.

The good news is I can be pretty sure the clutches are working quite well with little or no slippage.... The bad news is I may have to limit the way I change the electric transmission with the VFD driving the motor - it is obviously more sensitive (faster response time) to transients than the motor starter was. I have not yet searched the manual for a way to slow down its response time, but as it is now, I must slow the motor to about half speed to keep the transients from tripping the VFD when on gears 3 or 4. It doesn't trip the VFD on the lower gears or with the freq below 60 Hz.

I also welded the aluminum belt guard (keeps oil from the change gears off the belts):



The PIO must have changed gears at some point and moved the adjustable gear support to the other side of the banjo. Then when going back to the standard setup, the 51T idler gear hit this guard and he shoved on it hard enough to break the al casting. I Vee'd it out on both sides, and then welded the material back in. Here is a pic of the guard in place:

Originally Posted by RevetsP

Can you take it off and attach a regulated air line to it, and see if/when it changes it's switch state? I have another one from the same model I can test here today.

I will try to do this tomorrow or Monday....

Alright, I tried one of the other brake line switches, this one wanted to turn on around 50psi or so...

Originally Posted by RevetsP

Alright, I tried one of the other brake line switches, this one wanted to turn on around 50psi or so...

I did not get to the shop today - my better half designated this a "cleanup the house day".... But I should be able to make the measurement tomorrow if I can find the right pipe adaptors for my hose. Fifty psi may be on the high side for my 40 year old pump.... especially when I slow the motor below 60 Hz with the VFD. I did try cranking it up to 90 Hz (about 2600 motor rpm), but the ps still did not change state. I will also try to find adaptors to get a good guage on the pump to see what it is putting out.

How many of you guys with SAG 12 lathes (or the other models with the electric transmission) have measured the actual pressure output at the pressure switch with a guage? What pressure did you measure? I think it was Peter who said the Graziano rep told him it was supposed to be 3 to 5 atm (I took that to mean 1 atm = 14.7 psi nominal).

I put a guage on mine today and only see 25 to 30 psi - does that mean my pump is shot?

I would love to hear any inputs on this subject that any of you are willing to share.

To RevetsP: I need to make a 1/8 BSP "barrel" adaptor (F to F) to test your ps - but my low pump pressure means I have never had anything like 50 psi....

Pretty sure I've seen on this site a 12 rigged up with a pressure gauge in place of the switch/timer mechanism....with the change in the forum, pics most likely disappeared recently text might still be around??

Would have thought a brake pressure switch would have a fairly high cut-in. Not much pressure being exerted by your hand or foot, but quite a large lever ratio and coupled with a small master probably.