[mike sr1]

I found out yesterday what happens when the spindle is running, even slowly, and the PDB pushbutton is pushed, not pretty thats for sure! I had a repeititous job drilling holes, changing from a center drill to a regular one, and my mind wandered for a second, thats all it takes.........

I need to come up with an interlock of some sort that if the spindle is running the pushbutton will be disabled, it has one of sorts but its an after the fact, and the brake isnt applied after cutting the power to the spindle.

I am thinking that when the spindle is running a relay is energized, then maybe a normally closed contact in series with the pdb power so that if the button is pushed when the spindle is running there is no power to the pushbutton to cause it to try to release??

any thoughts on this appreciated....

[freeidaho]

Mike,
How long after the power is removed does the spindle coast. Is that time an issue too?

kr

[mike sr1]

It coasts quite a long time as the braking resistor isnt used in that instance. I would think an interlock would be the way to go, I was going to check to see if a relay is used when the VFD is switched on. I have had my machine over two years and this is a first for me, I dont want there to be a second time! Luckily It didnt destroy my balancing eccentric rings and the screws left a mark, so I just put them back in that location, and no vibration so it must be close....

[TurboStep]

Hello Mike, maybe I'm slow but I don't understand how you're controlling the spindle. Are you using the manual controls?
Step

[mike sr1]

Hello Mike, maybe I'm slow but I don't understand how you're controlling the spindle. Are you using the manual controls?
Step

Yes Turbo, I am, I was drilling holes to a depth using Z. I then shut the spindle off to change tools, its a quick operation and I pushed the wrong button first, totally my fault.

[TurboStep]

I pushed the wrong button first

I thought the brake was also used when controlling the spindle manually - I'll have to check that out.
Step

[neilw20]

It runs from a VFD?
Many VFDs have 1 or 2 output relays.
You can program one of them to use the closed contacts only when the spindle is stopped.
Use NC contacts, when stopped. Program so that when above, say 20RPM the relay operates and contact opens.
The 20 is not your programmed speed but the actual commanded speed, internally within the VFD as it ramps down/up

[mike sr1]

Turbo,
It does work in manual mode as well, but when the pdb switch is pressed it kills the spindle but doesnt apply the brake. Very similar to opening the spindle door when the machine is running, it kills power but doesnt apply the braking resistor.

The print is so small I cant read it comfortably without a magnifier, maybe I need to make a trip to the copy shop and have one made for old eyes ha!!

I just need a short carbide drill and I wouldnt have the double op with the center drill, I dont have many of these to do though.

[mike sr1]

Neil,

There is a relay that pulls in on startup but is independent of the spindle once its started, it remains energized.

[neilw20]

That will be the safety relay that remains energised. Drops out if you hit ESTOP.
Hope you don't use estop to stop normally.
Ask Tormach whether there is any interlock between spindle motion and the PDB.
The relay I speak of is internally in the VFD. May or may not be used. Ask Tormach.

[TurboStep]

but when the pdb switch is pressed it kills the spindle but doesnt apply the brake.

Well, I'm getting there slowly Check out my post in an earlier thread:
Link: http://www.cnczone.com/forums/tormac...ml#post1247496
Lower down in the same thread I reported that I had actually tried it, and it works! My mill has been connected this way since I posted with no ill effects. In the current ATC manual can be found here:
http://www.tormach.com/uploads/416/U...1013A-pdf.html
I just used an old phone cable with an RJ11 connector. The description on page 11 refers to the black and red wires but cables may differ. I'll try to post the exact connection info later today.
That should solve the problem of the spindle but it doesn't protect your fingers - take care.
Step

[TurboStep]

I checked my installation and I also use the black and red wires. My cable just happened to have the U.S. Bell System colors as described in the following Wiki:
Registered jack - Wikipedia, the free encyclopedia
Mine is a 6 pin connector but with only 4 wires. Pins 1 and 6 are not used.
I just tested it again to make sure that it was still working and it works perfectly!
Step

Edit: by working perfectly I mean that the PDB doesn't activate while the spindle is powered. The spindle continues to run - it is not stopped.

[mike sr1]

Step,
I apologize for not explaining things better, I am not very good at that sort of thing. I do think that you have the solution to the problem though, In simplicity I just want the power removed from the PDB circuit while the spindle is running.
The way its setup on my machine, when the pdb button is pushed the spindle is powered down but the brake is not energized, its kind of like the old saying "closing the barn door after the horse has gotten out", as there is a delay from the time its powered down to the time it actually stops of a few seconds, there is a delay on the spindle stopping even if the brake would function as it normally does and the length of the delay varies by the spindle rpm. Luckily I was only drilling at 1500 rpm.

I was always much better at fixing machines than operating them and thats not good in this situation, as fingers could be lost etc.

The good part of all this is it didnt damage the spindle threads!
It also didnt affect my spindle balance rings as I could get them back in the same position after this happened!

[RussMachine]

What's the PDB button?

[nitewatchman]

What's the PDB button?

Power Draw Bar Button - could be either manual control button on headstock or foot pedal to control the power draw bar.

Energizing it with the spindle turning even slowly tends to disassemble the drawbar flange from the spindle. I have this on very good authority.

Also sounds really bad and stops real quick.

nitewatchman

[neilw20]

Bad things usually occur when 'showing off' to a visitor.

[mike sr1]

I checked my installation and I also use the black and red wires. My cable just happened to have the U.S. Bell System colors as described in the following Wiki:
Registered jack - Wikipedia, the free encyclopedia
Mine is a 6 pin connector but with only 4 wires. Pins 1 and 6 are not used.
I just tested it again to make sure that it was still working and it works perfectly!
Step

Edit: by working perfectly I mean that the PDB doesn't activate while the spindle is powered. The spindle continues to run - it is not stopped.

I called Tormach today and was told that it cant be done!
Thats all well and good because they wont sell me the cable you refer to, as it only comes with new systems with the PDB and ATC combined.

I think a 24 vdc relay normally closed held open in series with the pushbutton or the 12 vdc power supply should do the trick unless I am missing something. There is 24 vdc output on that cable that you refer to from the VFD and there is power until the spindle completely stops which is what is needed.

I may be missing something but I think it will work.

[TurboStep]

Apparently not all tech support is equal! I can assure you that it does work. Go to the earlier thread and scroll up and read Sp-4Renegades post. All it needs is a telephone cable. I'll PM you later today.
Step

[David C. Allen]

I also emailed Tormach about the part number for the VFD to Power Draw Bar cable and they also said it was part of the ATC kit and therefore they did not stock the individual parts or have a part number.

David

[neilw20]

You need to reinvent the wheel, it seems. And the setup is in the VFD, I suspect, if you can find that information.