[Gyro_Gearloose]

Hah, was I ever proven wrong!

With orders and production volumes up in the skies, I haven't had time to do anything more with that machine until a couple of weeks ago. But finally I had some "spare" time to give our mill a little TLC. When checking, I found the main source for the problems; the Regen resistor pack had developed a break in the circuit! Probably all these years in service, heat and lots of vibrations finally killed two of the resistors. It all worked fine when the resistors were cold, but a crack in the resistive material opened up when they got warm, and then there just wasn't any regen anymore! Without the regen resistor, the bus voltage soars to well over 600V (reading went off the scale of my trusty old multimeter) and BOOM! - regardless of new VDRs in the 325V line. (Yea, I replaced those as well when I took care of the servo amplifiers.)

But, I ordered a bunch of components; resistors, opto isolators and a new IGBT and replaced the whole shebang in the HV/Regen circuit w/o taking more time to troubleshoot. I also rebuilt the Regen resistor pack with new components and mounted a 12V fan inside it, fed from the AT PSU.
Imagine my happydance when I first started the spindle on 500 RPM and then stopped it without any errors!!!:banana:

Continuing to test with increaasing RPMs shows that that porion of the machine now is working accordingly.

So now I've taken on a new part of this restoration, elliminating the nasty crunchy sound that the driveline makes when running on 800RPMs and above. So far I've split the motor/gearbox and sent the motor to Finland for bearing replacement. At least the drive side bearing in the motor is shot. The primary gear is probably heat-shrunk onto the motor axle and there was no-one in this city that could get it off. Tornion Sähköpojat (Electro-boys in Tornio) has specialized in this kind of work so it should be a walk in the park for them to replace the bearings.

There is a grease cerk on the motor's end bell, but who the heck can imagine it's there, when it's hidden by two covers? I'll also replace all bearings in the gearbox and also replace the tachometer driveline: The tacho drivebelt is reduced to just a rag and the drivewheel coming out from the gearbox is severely worn down. I'll contact our local Haas distributor on Monday and ask for replacements, if they - as usual - don't have any other solution than to replace the entire motor/gearbox assembly (which will cost a bloomin' fortune!) I'll contact one of my former schools and ask them to make a new drivewheel for me. Will probably cost us a cake or two instead of around $4000... I know they have the drivebelt but I didn't see the wear on the drivewheel when I spoke with their tech so it wasn't mentioned.

But now I see an end to this project, now my hope is that the machine will be back in service before the end of 2018, or at least in the very beginning of 2019. Do NOT wish me luck!

Best regards,

Gyro_Gearloose

[Cojaq]

"I also downloaded Tayfunk's circuit diagram of the VD, it helped me a lot when doing the initial troubleshooting, Thanks a bunch, Tayfunk!"

Hello Gearloose, I'm wondering if I could get the diagram of the VD from you?
I have been having intermittent issues with alarm 123 spindle drive fault. Nothing serious YET! I would like to avoid a complete shutdown if at all possible. I have read on numerous forums that this is a common occurrence, but no one seems to have a clear reason and surefire fix for this. I would prefer it if I didn't have to replace a bunch of unnecessary items. Most all of my measurements have been within the prescribed ranges for the items that are in the power and control loops. I don't know what else to check that has not been discussed and therefore I would like a diagram of any and all associated circuits. Thanks for any help.