Y axis is making X axis stall...!!

[fasteddy]

Wow Jazz.. Lots to chew on...

Ought eliminate a couple of potential probs tho... I am not daisy chaining the motors/drivers with power, all have there own separate feeds/wires.. Not sure what the voltage limit is for these motors and I have been frowning a smidge at the 24v power supply as a possible weak point.. But the y axis is not stalling, and my last cnc was driven by just that one 24v psu, and it drove 4 x 3Nm motors then with no probs like this one...

Was running Mach3 at 25Khz, ramped it up to 45Khz in trying to fix this prob and it made no difference (using a dual P4 board, 2 gig ram with XP in desktop PC mode) so I left it at 45KHz..

Driver test is fine..

By ground, you mean earth right? Connect 0v and or ground to earth? Read this many times but when I look into my box of tricks, there are an awful lotta grounds and 0v points, more if you eyeball the PSU's too.. Pass the aspirin...

Mid band resonance... Is this a resonant frequency of the machines mechanical structure? If so I doubt this is a problem as the motors are very smooth and pretty quiet (apart from that dull thump caused by backlash comp in Mach3) until the very sudden growl from the nema 34's when they stall.. The fact that they both stall, and bearing in mind they are slaved together in Mach3, still suggests something electronic tho... Also as both the y and x are running at full speed simultaneously suggests it might be power, so will get a new battery for my multimeter first thing tomoz...

Will drop the steps as you suggest and check some voltages in the a.m. Starting to get intrigued by earthing, really feeling the need to get that one outa the way..

Steve..

[JAZZCNC]

By ground, you mean earth right? Connect 0v and or ground to earth?

Yes by ground I mean Earth.
One Earth point which each mains device leads back too or picks up from.

Basicly all roads lead to Rome or in this case one earth point.

[Gary]

Are your phase cables and signal cables shielded?
If not you may find that noise is being picked up on the signals.
This may be hitting the direction signals and causing one of the x axis to be changing direction?
disconnect the direction signals on the x axis and see if it still happens.

[fasteddy]

Chicken or egg?

Not sure if the problem caused this, or if this is the problem... On the power supply for the nema 34's (x axis), I have just discovered a 'crispy' component.. Think its a resistor, I can only read '8K' on its blackened surface.. I was about to check voltage outputs from this PSU when I saw a tiny wisp of smoke come from it.. I have switched it all off and will contact the chap that sold it to me to see if he knows what it is..

Steve..

[Jonathan]

Chicken or egg?

Not sure if the problem caused this, or if this is the problem... On the power supply for the nema 34's (x axis), I have just discovered a 'crispy' component.. Think its a resistor, I can only read '8K' on its blackened surface.. I was about to check voltage outputs from this PSU when I saw a tiny wisp of smoke come from it.. I have switched it all off and will contact the chap that sold it to me to see if he knows what it is..

Steve..

Ahh must be a switching power supply, good luck getting that fixed. If something has gone wrong with the regulation circuit that would explain your problem.

I forgot to mention in my previous post that the stalling only occurred with mine at or near full speed, and completely went if I made X really slow (it was always X that stalled). This doesn't seem to be the case with yours... so I'm not sure. Maybe try wiring both X drivers to the same step/direction pins on the parallel port and disable the slaving as that should reduce the 'load' on the parallel port.
Also remember that the average current drawn by the stepper motor is not a simple function of speed...

[fasteddy]

Hi Jonathan..

Just emailed you again;

Just had a real close look at it with a loupe, I can see a single strand of wire from the +ve very close to the –ve.. Reckon it may have been arcing.. Tried to take a pic for you but my camera/phone cant take pictures that close and all I could get is a blur..


Part of me is relieved as this could well be the source of my probs... You set the the PSU for two outputs, 65v 8amps which I am pretty sure is fine for those motors.. Yes please, if you can send me a replacement rectifier, I will solder it on.. The -ve wire is also crispy so will replace that too...

Steve..

[Jonathan]

You set the the PSU for two outputs, 65v 8amps which I am pretty sure is fine for those motors.. Yes please, if you can send me a replacement rectifier, I will solder it on.. The -ve wire is also crispy so will replace that too..

Ok, I've got a few 35 amp ones lying around which should do the trick.

I'm a bit worried now you appear to be using this power supply with the PM542 drivers? I thought is was PM752. If that's the case it's bad as those drivers are only rated for 50V. I'll check in our emails what voltage the transformer actually is/was.

EDIT: Nevermind, that's me being an idiot...it's the PM752 so not a problem.
I really need to go now.