Cutting Some Signs! #95 - Mystic, CT

[alan254]

Hi Sean,

Yes it did.

In Mech 3 “general config setup” I turned on “set slave with master axis” the dragging seems to have gone away.

On that screen there is a field charge pump on in e stop. Should that be on?

Spindle now stays on at rest. When cutting woodpecker in air the spindle did out and the program kept right on moving as if it was cutting. I will play with de-bounce some more and keep on trying things.

Al

[alan254]

A little more experimenting. I start by turning on the spindle with the vfd, I execute a program it hits a command line with a "M3" and the spindle shuts down and the program continues.

Lost again.

al

[timberlinemd]

M3/M5 codes are On/Off for spindle. Try leaving the spindle off and see if it comes on when you get the first M3 code (spindle ON)

[alan254]

cannot do that since i am using the relay on the pmdx-122 to turn on the vdf, I can rewire this so the load contactor stays on and the relay only starts the spindle within the vdf. Then have the e-stop turn off the contactor and the bob to start and stop the spindle. If you think that will be better.

Thanks

Al

[timberlinemd]

I do not own a spindle (yet), so my contactor is wired so the BOB (G540) turns the router on with a M3 code and off with a M5 code (setup in Mach3). Without a VFD & spindle of my own I'm out of my element.

[bradm]

What are the connections from your PMDX-122 to the VFD? Contact closure only? Or speed control as well? What is your VFD programmed to do on contact closure? Start up or shut down?

If you're only doing contact closure, then it sounds to be like you either need to invert the pin value, or adjust the VFD programming, because you are getting a stop instead of a start.

[alan254]

Hi Brad,

PMDX-122 - J7 - no- contact closes and pulls in contactor coil, contactor energizes the VDF. That is all I have at this time. I start the spindle from the VFD.

One step at a time. lot to learn I will play later.
I could go in and edit the code and take out the M3 command, but would like to make it run properly.

I am willing to rewire the contactor coil into e-stop and tie the relay on the PMDX so it will be only act a reset if that is the correct way to go.

I would like it correct.

The main question is. Should the VDF contactor keep the vdf live.Then for a reset/stop stop the spindle and a true e-stop drop contactor from suppling the VFD.

If the VFD is de-enedgized, I believe, also lose the ramp down / breaking of the spindle. Not safe.

thanks

AL

[alan254]

edited out the M3 code all ran fine.

now to correct the problem.

al

[bradm]

Generally, you do not want to turn the power supply to the VFD on and off. In fact, I bet your VFD manual says not to place a contactor between the VFD and the breaker.
And never place one between the VFD and motor.

Imagine that the spindle is running at full speed. Now pull the power. Inertia keeps the spindle spinning, and it's now a generator pushing power back at the VFD. However, the VFD doesn't have any control power anymore, so it can't do anything about it.

If the spindle is running at full speed and you tell the VFD to stop, it shunts the power coming from the spindle into a braking resistor (internal for small VFDs; an external device for large ones), and it can bring the bit to a stop much faster than just freewheeling down. It also prevents any power transients and spikes that arise from breaking open a contactor under load.

So the VFD should be on all the time that the machine is on. You should use the relay to provide contact closure to the VFD as a start/stop signal.

If you want speed control, we can discuss a simple circuit to do that.

[alan254]

I will change that tomorrow. Yes, I would like programing and / or Mech3 to turn on and off and speed would be nice. I do appriciate all the help and hpoe I can help others in in the learning process.

Thanks,

al

[Gerald D]

Brad, there is typically a contactor on the VFD input, but this is used for the morning switch-on, evening switch-off and e-stop only. It is not used for starting up the spindle every time you make a cut.

[KenC]

Anyway, I don't know what other VFD does, but if you put a relay in front of the my type of VFD, it won't start the spindle (not in a million years) & it can't switch off the spindle at the instant you cut the power to the VFD...

[alan254]

Hi Gerald,

That was my originally thought on how to wire a VFD.

Thought this site some say E-stop and >>>> some say E- stop meaning what I would call a reset. Maybe we should call a RESET a reset a not E-stop and an E-stop an E-stop.

At least, being a novice, the like terminology confuses me on occasions, as I am sure it does others.

This stop/reset example of how I made error in judgment error since we never make mistakes.

I am offering this in a positive way, this is a great site.

Thanks,

Al

[Gerald D]

(E)mergency-stop is only used for smoke, flames, blood and screams.

[TechGladiator]

Originally Posted by Gerald D

(E)mergency-stop is only used for smoke, flames, blood and screams.

Do those screams include the ones from the wife yelling to get other things done instead of playing with the machine?

[WTI]

Originally Posted by KenC

Anyway, I don't know what other VFD does, but if you put a relay in front of the my type of VFD, it won't start the spindle (not in a million years) & it can't switch off the spindle at the instant you cut the power to the VFD...

Depending on your VFD, a large braking resistor can be installed that can stop the spindle within a half turn (so they say, I have no way to measure that).

The braking resistor on one of our mills looks like the coil from an electric stove (it could well be). The moment you hit the E-Stop, the VFD dumps all the power into that coil.

Check your VFD owners manual on installing and sizing a braking resistor.

[WTI]

My dad says that braking resistors in mills used for tapping will stop the spindle in a quarter turn - but you are tapping much slower than milling.

He says a 1 second stop time might be a more realistic number, maybe longer for a really high speed spindle.

[alan254]

Thanks all.

Made all the wiring changes. Now. I like how the VFD reacts. Made several cuts, like I can cut half of the roadrunner only because I did not recieve my licence from Mech3 and cannot load all the code>>>>> I hope. It cut nice, starts and stops with the code comands M3/M5 commands, can stop and start Spindle on the touch screen.

Now Brad how do I contol the Spindle speed on screen?

Anyway it finally cuts and I think I made a record of the longest build time. tust shy of 36 months

Now comes the hard part How does it run? Hopefully less than 36 months.

Once again thanks all.

Al Drouin

[KenC]

Seems like I didn't get my point clear.
To rephrase.
The VFD display takes about 6 seconds be fore it starts blinking & another 4 seconds for it to get ready for operation after the VFD is connected to external power & to get the spindle turning, one need to press the ON button on the VFD or receive a signal from the PC after the VFD display is ready..

Hence, "if you put a relay in front of the my type of VFD, it won't start the spindle (not in a million years) "

The VFD display will only black-out after about 6~7 seconds after the power supply is disconnected to external power.

Hence,
" it can't switch off the spindle at the instant you cut the power to the VFD..."
& I've not got to the spindle breaking stuff yet...

All this is before we even consider talking about the physical breaking.

[MetalHead]

Pictures , Pictures , Pictures !!!

[bradm]

Al, you need an optoisolator, two resistors, one capacitor and a small hobby circuit board. You use a spare output pin from the PC, and treat it as a PWM output; one resistor is the current limiter for the input side of optoisolator; the optoisolator protects the PC and VFD from each other, and the remaining resistor and capacitor form an RC filter on the output from the optoisolator to create a 0-10v control voltage that goes into the VFD.

I'll try to run the actual calculations and draw a circuit picture a little later - I'm not at my desk right now. What is the make and model of your VFD?

[alan254]

Recieved Mech3 licence now>>>> we have a full roadrunner

mm 116.jpg

mm 118.jpg

[timberlinemd]

Show the machine

[alan254]

I will do that

[domino11]

He did,

Here
and
Here

Now all he needs is a serial Number! Congrats Al!

[MetalHead]

SaWeeeet - Congrats you get #95 ---- Can I hear 5 more .... I know your out there !!!

Nice build !!

[jhiggins7]

Al,

Congratulations on completing your MechMate and earning Serial #95.

Here is the Updated Builder's log.

As a guess, I've included the US MDF sheet size ( 97" X 49" ) as the dimensions. Please let me know the actual cutting dimensions of your MechMate.

Please review your Builder's Log entry and let me know any changes you want to make.

[Red_boards]

Congrats, Al

[bozona1]

Way to go AL

[TechGladiator]

Congrats Al!!.. Nice build...