Can't get spindle to turn on PCNC 1100, possible voltage issue?

[CastorTroy]

Well it looks like I'm having a strange problem. I have an older machine (PCNC series 2 upgraded to series 3) that is giving me a strange issue. When I first power up I can't reset the machine on PathPilot for about 10 minutes until the machine "warms up". After 10 minutes I can reset and do things like jog the axis but when I got to start the spindle the relay clicks but the spindle won't turn. It turns out in my shop we have only 208 volts, significantly lower than the 230 that the machine was designed for. I had the issue of the machine not coming out of eStop a year ago but I replaced the Mach 3 controller to Path Pilot and the issue went away. The Path Pilot controller has been swapped out along with the DB25 cable. We have tested the J4 cable and it checks out fine.

I'm starting to run out of ideas what could be wrong with the machine and the only thing I can think of is that since it is older (mfg 2008) the electrical components (i.e. the VFD drive) are ageing and the lower voltage is causing an issue. I'm considering getting a boost transformer to rule out this issue regardless but I wanted to find out if anyone else had this issue?

The feedback would be greatly appreciated!

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[jwatte]

I hate to ask, but: Does the spindle turn manually?

In my experience: When things start dying after > 5 years, it's often capacitors. Capacitors in electrical components do wear out, and they wear out faster in equipment from low cost manufacturers than in equipment specified and manufactured to "telecom" or "military" grade. It's a fact of life. So, assuming the spindle turns fine manually, I'd give this a >50% chance of being a capacitor somewhere.
Now, it may be a capacitor on the inside of some separate module, rather than something you can easily replace like an AC motor start/run capacitor. If it's inside a power supply, you'd probably have an easier time replacing the power supply, than trying to isolate and replace the individual capacitor on the inside.
Given that, the next step might be to measure the output voltage for the power supplies. If it works after 10 minutes "warm up," it's quite possible one of the power supplies (12V or whatever) would need that time to get the charge of the worn-out cap up to the point where the power supply signals "power good."
Get out the wiring schematic and the multimeter to verify the power rails!

If that all looks good, the next step might be on the inside of the VFD -- there are capacitors there, too. Opening the box and starting to look for test points to measure might be feasible if you have the diagram for the unit and are used to electrical service and repair. If not, then let's hope that's not it ...

[CastorTroy]

Hi jwatte,

Thanks for the feedback. As far as I know the spindle turns manually because I could get it to go in reverse last week. I'll try turning it manually tomorrow and report back. Although this week I can't get it to either direction in manual mode.

I also think there is a capacitor that is going bad but am struggling to find out where. There are two caps on the machine control board, a large one on the upper right hand section of the panel. There are also some inside the VFD and I also have the noise suppression kit so three extra caps have been added. Anyone have any ideas which it could be? I'll test and report what I find.

Tormach has a procedure for testing the VFD that I found today : https://www.tormach.com/wp-content/u...art_issues.htm

I'm going to look at that tomorrow as well as I believe there are caps in the VFD as well.

Thanks for the help so far! Can't wait to sort this out!

[Karlwinter]

Well it looks like I'm having a strange problem. I have an older machine (PCNC series 2 upgraded to series 3) that is giving me a strange issue. When I first power up I can't reset the machine on PathPilot for about 10 minutes until the machine "warms up". After 10 minutes I can reset and do things like jog the axis but when I got to start the spindle the relay clicks but the spindle won't turn. It turns out in my shop we have only 208 volts, significantly lower than the 230 that the machine was designed for. I had the issue of the machine not coming out of eStop a year ago but I replaced the Mach 3 controller to Path Pilot and the issue went away. The Path Pilot controller has been swapped out along with the DB25 cable. We have tested the J4 cable and it checks out fine.

I'm starting to run out of ideas what could be wrong with the machine and the only thing I can think of is that since it is older (mfg 2008) the electrical components (i.e. the VFD drive) are ageing and the lower voltage is causing an issue. I'm considering getting a boost transformer to rule out this issue regardless but I wanted to find out if anyone else had this issue?

The feedback would be greatly appreciated!

If this machine has a thermal breaking resistor I strongly recommend looking there for your spindle concern. . There is a little push button to reset it. Look in at the enclosure on the z axis up right side.
Also make sure your up to date on software.

[CastorTroy]

Hi Karl,

Thanks for the suggestions. As an update I have tried to turn the spindle manually by hand and it turns. I have gone through the link I posted on troubleshooting from Tormach and apparently both the VFD and the machine control board are good according to my voltage measurements. I'm trying to find the reset button you mentioned. Is this on the VFD with the cover removed? I have attached a picture but I really could use some clarification here.

[Karlwinter]

Hi
No it is not on VFD. BEcarfull poking in there.
Your picture is different than what my machine looks like.
It's on the column on the inside of the enclosure
I'll see if I can get pictures for you

[Karlwinter]

Hi
No it is not on VFD. BEcarfull poking in there.
Your picture is different than what my machine looks like.
It's on the column on the inside of the enclosure
I'll see if I can get pictures for you

Looking at a wire diagram from older models I dont see it has the thermal reset switch. This is out of the 1100m

[CastorTroy]

Well guys and gals,

Looks like I've found the problem. I measured the output between pins J1-1 and J1-2 after imputing a 1000rpm speed in the PathPilot window. The value should be about 1.41 volts and I am getting 0.29 volts. Similarly if you enter 5000 rpm the readout should be between 4-5 volts but I still get 0.29 volts. What this means is the board is bad but I think it's just a bad component. I think it might be the variable resistor that had gone bad but I could use some input here as I'm not an electronics expert. See attached picture. Any thoughts if I can going after the right part? Attached is a picture of the board. The potentiometer is the small blue rectangle on the upper left hand side.

[jwatte]

Do you have an oscilloscope? Is the output supposed to be a stable voltage, or a PWM duty cycle?
The way VFDs break, it's generally that the MOSFETs get burned; this could cause the voltage to stay low if it's generated from a PWM duty cycle.
The MOSFETs are the four black components screwed to the board in the top right corner of the picture.
That being said -- see if you can find a spare part for the board. Trying to debug this if you don't have a circuit diagram and an oscilloscope seems far fetched...

Hmm, or this might not be the VFD board? It says "tormach control board" in the lower right corner. Still, those black screwed/heatsunk packages look like a MOSFET bridge of some sort.
Can you buy a working card from Tormach? That seems to be the best way forward, given that you even have the part number on the board!

But ... I just looked it up, and it's over five hundred bucks!
https://www.tormach.com/store/index....show&ref=31045

[Henrik Adler]

Check Q1 at the upper left of the board.
It might be an isolated DC/DC converter, supplying power to the upper part of the H-bridge output transistors.
These tend to fail after some years.
Good luck.
Henrik

[TurboStep]

Earlier you wrote:

... As an update I have tried to turn the spindle manually by hand and it turns.

First just to check: did you mean setting the switch on the control panel to manual and controlling the spindle speed using the potentiometer or actually rotating the spindle by hand?
I wouldn't start replacing ICs just yet. There are some other tests we should do first.
Step

[CastorTroy]

Earlier you wrote:
First just to check: did you mean setting the switch on the control panel to manual and controlling the spindle speed using the potentiometer or actually rotating the spindle by hand?
I wouldn't start replacing ICs just yet. There are some other tests we should do first.
Step

I have the enclosure on my machine so the control panel that used to be on front of the cabinet with the "Auto/Manual" switch has been removed. So what I meant is I turned the spindle by hand to make sure it wasn't seized. You can only run the spindle on my machine in "Auto" mode through Path Pilot.

[jwatte]

Looking at the board some more, I see "REG1" and "REG2" next to two of the screwed-down TO-220 parts, so those likely are linear voltage regulators, not MOSFETs.
Thinking about it, there are relays, and the MOSFETs generally live inside the stepper controllers and on the inside of the VFD, so that would make sense.
Doesn't help you much, I'm afraid! And while a counter chip may be $1 (assuming that's the problem, from the other thread,) how much does your time cost, and how much do you pay in tools and shipping?
Only you would know how much that's worth, compared to just getting a new board.

[ShortTrack]

CastorTroy;

Let's back up for a moment... I got confused. (Smile)
* Does the mill still take 10 minutes or so to "warm up"?
* Do the X, Y, Z axis (and other functions work correctly)? In other words, the only thing "broke" is the signal to the VFD?

IF the only thing not working is the VFD, have you checked the interlocks that prohibit the VFD from running?
(I am guessing a bit on the hardware that your system has. Items such as Parallel Port daughter card, etc.)
_____

If the only thing NOT working is the VFD:
If this were me, I would NOT want to shell out $500 for the controller only to find out it wasn't broke... Assume you feel the same.

Oh, did you check the fuses on the Machine Control Board?

Here is how I would proceed:

0) Just for giggles, remove then re-seat every ribbon cable on the MCB and to the Computer. Do this one cable at a time so as not to get confused. While you are at it, re-seat the card in the Windows computer - assuming it is a peripheral card. Then test mill.
1) Find out what spindle control signals go TO the Machine Control Board (MCB). These go from the Computer via DB25 connector to a bulkhead connector to the MCB, IIRC.
2) Find out what spindle control signals go FROM the Machine Control Board TO the Emerson VFD.
3) Verify enable signals are present at the drive. IIRC there are some enable signals at the drive. Possibly the motor enclosure switch. I don't remember.

1) & 2) might be available online somewhere, or you might need to discuss with Tormach. I did not look.

Find someone with an Oscilloscope or a Logic Analyzer. These tools and the knowledge to run them are really required to verify the fault is in the MCB.

You will then command the spindle to move, your assistant will make sure the signal is going from the computer to the MCB, then will verify if the signal is making it to the VFD. They will also check to ensure any/all spindle enable signals present as inputs at the MCB & VFD.

This, IMO, is the only reliable way to make sure the MCB is at fault - other than swapping one with someone else that owns a Tormach! I don't think you will get many takers (smile)

As an aside, it is also possible to reprogram the VFD to operate manually, just to check that it works. I am assuming you do NOT want to do this, as you might forget or lose some of the required setup parameters for the VFD to run connected to PathPilot.

Best of luck,
-ST

[TurboStep]

I have the enclosure on my machine so the control panel that used to be on front of the cabinet with the "Auto/Manual" switch has been removed.

That's a shame, you might have been able to eliminate a defect of the output circuity of the controller board and VFD.
On the other hand, the measurements you reported in the other thread would indicate an issue earlier in the flow. If you have removed some circuitry are you sure you don't have any floating inputs? I've never checked this part of the circuitry in any detail, but then again, I don't know what you've actually modified.
You have multiple symptoms but it's not clear whether they have the same root cause. The reset issue would seem to imply that something is marginal. It might be useful to find out whether the machine or the controller PC needs the 10 minutes warmup. If this effect is repeatable I'd let the controller PC run but with the mill turned off. Wait until you're sure the PC has been running long enough and he mill is completely cool. It the mill still can't be reset for another 10 minutes after turning it on then the issue is likely to be on the controller board side (which does not exclude cables at this point).
Just for completeness, there's a yellow LED on the left side of the controller board labeled Spindle Speed. I assume this doesn't light up at all - is this correct?
The voltages you reported in the other thread might give the impression that the IC is defect but you don't measure anything on the clock pin either. What voltage do you measure on pin 1 of U21 (to the left of the microcontroller)? I measure around 2.5V when the spindle is running.
Step




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[nitewatchman]

Don't want to irrate the problem but is the door interlock switch circuit working on the head access door?

Pardon me if this has been asked but seems like a place to start. If the switch opens, the spindle will coast to a stop and play dead.

Gary

[Tormachmaster]

Where are you located? I have an extra board.

[Tormachmaster]

I believe it is the correct board