Vertical mill, VFD questions.

[Dragfluid]

Hi folks. I need some help with this. I have a Shizuoka ST-N mill. It requires 3 phase power and I have only single phase. I wired up and configured a VFD to it and there's no response from the machine at all. Not my first rodeo with a VFD, as I've been using one for the plasma table exhaust fan for a couple of years and have a good feel for the setup. I guess my main question is, will the computer system on the mill not play nice with the VFD power?
Any input appreciated!
Thanks!

 

[txvwnut]

Is the control circuit for the CNC part of it three phase as well?

Are there any fuses or breakers on the machine?

 

[Dragfluid]

No fuses that we're aware of. And just a main breaker that serves as the main power switch, and power is going through it. I got it from a good friend/wife's cousin. It ran shortly before we hauled it home, then it sat in the shop for about a year with no hookup, then I moved it up here to it's present (and last) location, where I decided to finally get it running.
There is just one power cord for everything.

 

[Dragfluid]

I've been trying to decipher what is the power input to the computer. I have the book on the thing, but it's still packed up yet in one of the unpacked boxes. This computer reminds me of my first IBM XT. You could use it for a truck jack stand.

 

[RPH]

I would think a parameter or two not set properly. I would expect to set the input parameter to single or three phase.
It may have an input voltage parameter too. Time for the book.
Another thought is the motor parameters in the Vfd.

 

[Dragfluid]

There are no parameters in the VFD to dictate input voltage. That's done by a choice on the input wiring.

 

[RPH]

Are you trying to run the controls and motor from the Vfd? Or just the motor?

 

[RTM]

My concern matches RPH. I suspect you've got a control system issue keeping the XT from running. Try powering it up separately from the motor, see it that helps. I know some electronics don't like generator power, and an XT architecture is old and funky.

 

[Dragfluid]

Yes, everything just from the original power cord. And you both have valid concerns. I found the plug in on the computer and managed to get it unplugged. Just a typical computer power cord. I should have about 47 of them around here. I'll put some conventional power to it and see what happens.
Also, after opening about 10 boxes, still didn't score the book. But I found one online,,,,,,,,,, free. After looking at the rather drab web page and crossing myself 5 times and gritting my teeth, I clicked on "download" and all 92MB came through, and my computer isn't on fire or dancing across the room.

 

[Dragfluid]

Found a cord and plugged 'er in. Heard the whine of a cooling fan, walked to the front and the screen was alive with ancient choices of writing to CMOS, etc. Waiting to hear back from previous owner on how to progress through the screen, as it's giving me choices of buttons that I don't have. The book shows a completely different control head.

 

[Dragfluid]

Got a call back from PO. He's never had the pleasure of dealing with the CMOS screen. I need to get the cover off the computer and find the battery. Hopefully I have a replacement, otherwise another 12 mile trip to town.
Had also found a manual on the Centurion 1 controller, but so far nothing on CMOS setup.

 

[Dragfluid]

Opened it up and found the battery. A little different than what's the norm. Went to a Battery Plus and they rebuilt it with a couple of new cells and now back in. Called Milltronics, left a message, got a call back in a half hour! The guy sent me info on what the CMOS specs should be, but apparently wasn't clear on what I wanted, as I need to know how to scroll through the screen. Too late to call back and get anyone, so called and left a message and hopefully will get another call back on Monday.

Jump in any time, guys!

 

[Firebrick43]

Using Romex to and especially from the VFD is a bad idea.

It’s insulation is not rated nor is it shielded and that can cause all kind of odd issues with the control electronics.

Why use VFD rated cable

 

[DocsMachine]

The guy sent me info on what the CMOS specs should be, but apparently wasn't clear on what I wanted, as I need to know how to scroll through the screen.

-That may be an issue. I'm not well-versed in such things myself, but generally speaking, a common issue in older CNCs is the memory backup battery going dead. Basically like the BIOS battery in your PC dying.

What that does is you lose what are usually called parameters- some of the base settings for the machine. Internal stuff that you, the user, never need to deal with, like leadscrew rates, "soft" stops, servo ratios, encoder "home" positions, and a bunch of other things. In many cases, the machine can't be used until those are restored or reset.

If you're lucky, you can find a copy, from the factory or online, of parameters for the machine. Even sort of generic ones, that will get the machine to where you can fine-tune from there.

If you're not lucky, you might have to do a lot of legwork and Googling to make something work.

Fair warning.

Doc.

 

[laser3kw]

VFD's output a square wave 3phase. The CNC will not like that and the vfd may damage the controls. You will need a RPC (rotary phase converter) or similar that will output a 60 hz sine wave three phase

 

[Dragfluid]

You guys must not have read what I wrote previously.
I have the computer plugged into the wall separately. It wouldn't fire up from the VFD at all.
And I do have a floppy that has been sealed in a pack on the computer panel. It is labled "Machine Parameters", and I think now, I'm going to insert it and reboot and see what happens.
Thanks!

 

[RTM]

Jump in any time, guys!

sitting back here cheering you on. Know nothing about CNC stuff, but I do know old industrial automation problems.

The comment above about ROMEX is spot on for several reasons, but back in the day, before we started using well shielded cable, we had a guy knocked on his **** from induced voltage in the cable.

Nice find on the floppy, stand back and let it boot!

 

[American Locomotive]

You can NOT use a VFD to feed 3-phase power into the mill like you are doing. VFDs are meant to drive a motor directly and nothing else. That is why nothing is working.

They can't be used for general single to 3 phase conversion. If you want to power the mill, you will need a rotary phase converter, or a phase-perfect type system.

The other option is to configure the CNC's servo amplifiers or stepper controllers (whatever they are) to run from single phase, which may be possible if they are DC (which they appear to be), and then integrate the VFD into the mill to directly run the spindle.

Edit: I looked more closely. The spindle is directly controlled by the switch on the front. The CNC controller has no control over the spindle.

The servo amplifiers have a single phase bridge rectifier feeding a capacitor. So it should be simple to convert that to single phase operation.

You will need to re-wire the head of the mill. The motor will need to connect directly to the drive, and the on/off/on switch will need to be wired to the VFD's control inputs.

 

[Dragfluid]

Well dang, and other adjectives! The floppy drive appears to be dead. The pilot light on it never lights. Will have to wait until Monday to ask if this disk is a boot disk or if it just has data on it. If it is a boot disc, then I can wire up another drive.
Interesting about the "no romex allowed". So you're saying that current will travel along the outside of the casing? Yikes! OK, then I need to change that. Thank you for the info!!
Thank you also, AL on your info. This whole shootin' match may just be placed on a back burner for now. I still have a few things to get finished on the plasma table, and that and the powder coating are my primary interests. The mill is secondary. Plus, there's still about 30 boxes of "stuff" that need to be opened and put away so this place will stop looking like a cluster F.

Much appreciated, all!!

 

[laser3kw]

You ask questions, we give answers.
As long as the CNC is a good servo type, you can retro fit the controller with one of the many DIY kits. Most are plug/fiddle/play.

 

[American Locomotive]

Well dang, and other adjectives! The floppy drive appears to be dead. The pilot light on it never lights. Will have to wait until Monday to ask if this disk is a boot disk or if it just has data on it.

If the computer was set to boot from the floppy drive, and the drive was dead, you would get an error (since this controller is based on PC hardware). More than likely there is a "load parameters" or "restore parameters" option somewhere in the control that will load the data from the disk.

 

[Dragfluid]

I just remembered that I have a fairly new 7 1/2 HP 3 phase motor sitting here. I'll just use that for a roto converter.

 

[matt_i]

You'd do well to study the wiring diagram of the machine that hopefully is within the manual package. Sounds like you have the PC part of it powered up but the OEM should give you everything you need as far as the utility requirements. Its also extremely important from the wiring diagram to determine what voltage it was previously configured for (and thus if you have to reconfigure). While you may know this from the previous owner, if you didn't, it can cause a very big problem. Big enough that you'd never want to guess about it in the future.

Ideally it would be single phase for the controls and 3 phase for the spindle motor only, or there was a way to separate the two. Then you can use the VFD to power the spindle motor and just accept a "run/stop" input from the controls.

If your controls have any possibility of running from 240vac x 1ph or 120vac x 1ph I strongly urge you to use that. Utility power is so much cleaner than the "dirty" power you get from a rotary converter. 3phase AC motors are robust devices that are largely insensitive to phase-loss as long as they aren't under a lot of mechanical load and as long as you don't try to start it on single phase (it won't, and will die in a locked-up state)

 

[RTM]

Most industrial machines I've worked on in the past simply pull off one leg of the 480 3 phase for the controls, and nowadays, many put a 120 vac => 24 vdc step down transformer on board to get human control like buttons and lights.