Messages

1

General Mach Discussion / Gecko G540, the A axis only moves into single direction

« on: October 20, 2014, 02:03:32 PM »

The A axis only moves into single direction.
I've attached my settings bellow, when i connect the same motor to any other axis X, Y ,Z it does move into both dirrections as it should.
I've never used this axes before on this controller so i'm not sure if it ever worked.
I have 2 keys set to move the A axis, "z" keyboard key and "x" keyboard key, and when i press any of them the voltage on pins 6-7, 8-9 does change and of course the're set to move the axis into different directions.
I can't figure out what's wrong, is it the controller or i have some wrong settings
Please help, thanks in advance

2

General Mach Discussion / Re: How to correctly ground very noisy spinddle

« on: July 08, 2014, 08:36:09 AM »

Adrian,

You still need to treat these series supplies as a single unit, that is; you need to filter the DC output. Supplies in series is not a good method unless they are all exactly the same voltage and current rating. What would probably work to quiet this supply down is a motor run capacitor or even a motor start capacitor - of ample voltage of course. Or better yet an electrolytic of ample voltage and capacitance - (like 1000 uF or above) Stay above 100 V and I believe standard motor capacitors start at 180 V (for a 120v motor). Grainger usually has these on the shelf....but these don't go very high in capacitance working with AC motors...

Also be sure to put a bleeder resistor (~47K Ω - 5 watt) across the capacitor for safety's sake - you're working with lethal voltages there. And - filter at the output of the supply, not at the motor. If anything at the motor a high voltage ceramic capacitor (about .1 uF) across the leads will help too. That will help quash some of the bask EMF that your seeing.

Careful with those voltages!

I'll add the resistor and motor capacitor to see if i'm getting better results than with electrolytic capacitor
thanks

3

General Mach Discussion / Re: How to correctly ground very noisy spinddle

« on: July 08, 2014, 08:32:47 AM »

Um - OK.

I suspect, from that info, that the PS you had been sold with the spindle, was a VERY crude switch-mode unit emitting huge amounts of RF. The RF would have been heating the motor. The laptop units will be made to a much highr standard simply because they have to be, to get FCC aproval. Oh well, hooray for Standards!

You could use the original PS IF you filtered the output well: a series choke and a good shunt capacitor (or two) should work a lot of good.

Regardless: earth one end of the overall PS!

Cheers
Roger

What would be the correct value for choke? I already tried a 200V electrolytic capacitor without choke, and it got hot within 1 minute
thanks

4

General Mach Discussion / Re: How to correctly ground very noisy spinddle

« on: July 05, 2014, 03:40:41 AM »

The laptop power supplies are all OEM, Sony Dell and IBM, so the voltage cumming out of them is stable.
I'm sure the spindle power supply made of laptop adapters is good, except the fact it's not AC grounded because:
1. With the original spindle power supply the spindle was getting warm-hot to 55-65 Celsius within 10 minutes of work
2. With laptop adapters it is 40-45 Celsius after 30 minutes, doing the same job, and motor works smoothly, i can hear it's running much better on these laptop adapter rather than on that cheap power supply it came in by default

5

General Mach Discussion / How to correctly ground very noisy spinddle

« on: June 28, 2014, 10:53:49 AM »

I have a very cheap 90V, 200W spindle, in order to power it i'm using multiple laptop adapters connected in series (of course none is grounded to AC).
The DC output is 96V. I've changed the cable today on the DC side, to a cable that has the ground wire. If the spindle is turned on, when i measure the DC voltage between ground wire and minus(-) wire or ground wire and plus(+) wire i'm getting crazy high voltage pulses 200-600V.
So my question is, am i getting all that noise due to my inadequate power source?
Should i connect the DC minus(-) to the ground wire?  (The ground wire from spindle is already connected to the CNC and all other ground wires from stepper motors )
Should i connect the DC (-) from spindle to the minus(-) DC2 output that powers my gecko board and all that to ground CNC?

The system seem to work well the way it is right now,  but i'm worrying  about the expensive gecko board.

Before changing all the cables to cables with ground wires, even with debounce interval set to 2000, i used to get some unexpected "Emergency mode activation"

thanks