Hello Vernon,

When you say you have a 24volt and a 100volt transformer, do you actually mean you have two DC power supply units (PSUs) i.e. 24 volt DC and 100 volt DC.

I would carefully check the two PSU cases are connected to earth.

Mike

I’m afraid your description is too vauge to provide advice. As a minimum the make(s) and models of the “transformers” (almost certainly DC power supplies) and spindle motor.
When you say it fails when the spindle motor is “connected” do you mean running or literally if connected? How are you turning the spindle motor on and off?
Mike and Bazyle’s comments are pertenent but a better description of the situation is required. A photo or photos of the machine might help too.

Robert.

I agree – more information about the setup please.   A circuit diagram and photos would help.

No proof but I suspect the computer running GRBL is being confused by electrical noise generated by the 100V spindle motor and it’s power supply.   I’d look for ways in the two are coupled together: shared power supply, cables neatly bundled together in a loom, long wires leading to the GRBL’s input/outputs.

These days one or more of the power supplies are likely to be switched mode rather than transformer based.  Switched mode units are lighter, cheaper and more efficient than transformer supplies,  but they work by generating sharp radio frequency pulses.  Cross-coupling occurs in ordinary power cables because these behave like inductors and capacitors at RF.

Ideally the input and outputs of are a switch mode power supply are carefully filtered.  Sadly, filtering is expensive, so it may be missing or inadequate on a cheap unit.   The answer may be a better made power supply.

But before that, work through the wiring:

• Don’t run signal wires parallel with power lines.
• Keep wires as short as possible.
• As the 100V supply is suspect, try reducing coupling by routing it away from all other cables.
• Earth all the wires in the electronics to a common point.  (NB.  This is a signal earth in addition to the safety earth, not instead of.   The purpose of a common signal earth is to prevent RF earth loops, because these cause cross-coupling.)

If none of that doesn’t work there’s a lot more that can be done, but it gets complicated.  Providing more info allows attention to be focussed on likely causes, rather than expensive guess work.

Dave

On 6 March 2024 at 10:43 John Haine Said:

…

Have I just discovered a bug?  When I “quote” in Jack’s post  718369 above I get quoted  Dave’s text instead.

Are you sure about that, John ?

Old habits die hard … and the relevant menu bar is now at the top of a post,  when previously it was at the bottom.

MichaelG.

On 6 March 2024 at 11:59 Michael Gilligan Said:

On 6 March 2024 at 10:43 John Haine Said:

…

Have I just discovered a bug?  When I “quote” in Jack’s post  718369 above I get quoted  Dave’s text instead.

Are you sure about that, John ?

Old habits die hard … and the relevant menu bar is now at the top of a post,  when previously it was at the bottom.

MichaelG.

 

Ah yes.  And of course there is no clear delineation of the division.  Thanks Michael.