Having just read the thread we have just been through this procedure with a satisfactory outcome. Initial problems where switching on a florescent tube, tool grinder, clicking stop button on Mach3 the U.S.B. Led would go out, pro gramme not responding. Only way out to reload windows & start agn. The mains power supply was fed from the house. Having 3 phase in the workshop  a new supply for the computer was installed from L1 this used for the computer and stepper drives. The auxiliary relay box with its own P,S. fed from L3.    When switching off the same result. In my build a mains filter is fitted to each transformer supply also in series with the aux. relays a thermistor of 4-5 amps current  with a 100 ohm & 0.1 across the contacts( Mill, Vacuum waste, Vacuum table. ).
               Using the computer case as a central point, connect an earth wire to the smooth stepper metal box, stepper P. S. and drives.   In my case removing the smooth stepper C4 & R5 made no difference. A new U.S.B.  cable was fitted but no difference . Fitting a suppressor across the manual switch cured the tool grinder,the motor being a capacitor start motor, before when switching off, would knockout Mach3  you could even see this on the red disc drive l.e.d. One mod worth doing is fitting a 25- 50 mf. condenser across the common feed going to the smooth stepper end of travel limits input. When these micro switches where gently tapped with a handle of a screwdriver out goes Mach3  so with the mill & steppers in operation a small amount of vibration could  cut mach3.
              Its a job to quantify but the main improvement in my case was fitting earth leads from the computer case to each item, mach3 would still knock out but the Red U.S.B. flashing feed light still good.   Fitting the suppressors across switchable items cured the crashes , its now a reliable machine.  
      
                

Hi,

Nice to see that you resolved your grounding/interference issues!
My SS sometimes resets whern static jumps between my vacuum hose and the machine chassies when I touch them together while running a program.
Would you suggest I ground the machine to the same ground as the protective earth on the driver powersupply or to the OV of the psu? Grounding is complicated business!
Also, what kind of suppressors are you using?

Thanks,

Daniel

My SS sometimes resets when static jumps between my vacuum hose and the machine chassis when I touch them together while running a program.

Many moons ago I used to repair copy machines. Vacuuming out the toner produces more static electricity than you would believe. One thing I learned was to touch a piece of grounded metal on the machine with one hand while vacuuming with the other. This keeps the static charge from building up on your body or the vacuum hose.

It is also common practice with dust collectors on woodworking equipment to run a grounding wire through the hose. I used some bare 22 AWG copper wire and looped it through the hose about once every foot. By 'looping through the hose' I mean that I basically put a stitch around one of the ribs so the wire wrapped outside to inside and back. A few dabs of silicone seals up the holes in the hose made by the wire.

Thanks, great tip!
I ran a beefy wire from my machine to the ground-point in my control enclosure, that can't hurt!
Will test/poke it some more!

       Thanks for replies, niece one Jeff about tube wire, you always learn something every day. With my setup it its mostly start & stop of aux.gear. So for switch on use in series a typical thermistor  5-8 ohms at 4-5 amps  R.S. 516-7811 8R-4A  or  R.S. 516-7827  10R-5A  with the relay contacts.   For off use Farnell 143-8457 contact suppressors across the relay contact.   These come with a reasonable length lead to fit across a octal screwed base .
                                  One other tip if you are running a Industrial type vacuum cleaner with its own motor cooling fan on 240v. put a 240V - 110V transformer between, its certainly cuts down the noise level and still has plenty of suction.
                                              Regards    Hollydog    

I need help with the suppressor.  I have found that the only way to keep my SS running is for the stepper motor power supply to be plugged into an outlet that is on a different circuit which means stringing an extension cord across the garage.  While this is not earth shattering, it is still a pain.  When I do turn off the power supply switch, it locks up the SS and Mach.  What kind of suppressor can I use and how do I connect it across the DPST switch?  My power supply is also in a plastic enclosure, so I will have to work on grounding each of the components.  Thank you!

Hello docrawfo,
                 These suppressors are only 0.1yf & 100 ohm in series across your switch open contact. Not knowing your country I would have thought that you could obtain them from the numbers. Its the back E.M.F. that causes the problem, possible another way when all else fails is to put a resistor of suitable wattage in series with the Transformer with a switch across the resistor to soft start and switch off. But be careful of the mains it can bite?  Pity you could not make the P.S.box metal.  In actual fact by running a long mains lead you are putting some resistance in circuit.
                                        Hollydog