[tauscnc]

Hey guys,

I have a question. In the quest to get every bit of speed out of my router (I know I know) I am seeing where my geckos 320s fault or my motors crap out .

At the highest settings I can "get" if I run them individually they are fine.

If I run 2 motors they are fine.

When I run three at once they fault.

Is that a sign that all three motors are taking:

1) to many amps out of my power supply
2) My computer cannot handle the Hz I have mach 3 set on
3) Accel is to high for my motors

I have played around for sometime to figure this out and did find turning down the accel was usefull. Please note I have NO clue how to actually setup servos and am acutally trying for real this time.

Want 300 IPM or more if possible very close

Machine K2 3925
Servos 305 oz/in from K2 DGM 2800 rpm 50W 3.5A
Gecko 320s
10 amp 24 v power supply
2.10 Ghz 512 RAM computer.

Thanks!
taus
www.cuttingedgecnc.com

[Bubba]

Tauseef

OK, will try to take a crack at this based on the information that you have given plus some that I have done on the K2 site.

Given information:
Machine K2 3925
Servos 305 oz/in from K2 DGM 2800 rpm 50W 3.5A
Gecko 320s
10 amp 24 v power supply
2.10 Ghz 512 RAM computer.

Possible system information needed as gleaned from the K2 site and correct me if wrong:
Ball screws and I assume 5 TPI
2:1 reduction on the servo to ball screw.

OK, with a 24 V power supply, the maximum you will be able to turn the servo motor is 2800 rpm.
With a 2:1 reduction ratio, the lead screw will turn no more than (2800/2) 1400 rpm

A 5 tpi ball screw has a pitch of .2 inches so there fore, we are looking at .2 *1400, or a max of 280 ipm!

So far, absolutely no way to achieve 300 ipm! Now, according to Mr. Gecko himself, in a mail that he wrote to me:

“……… so even the smallest torque disturbance at deceleration is enough to overload the motor, causing it to fall behind the commanded location. This position error faults the drive.”

To prevent this problem, we should not run the motor at more than 80% of max rpm or in your case, .8* 2800 or 2240 rpm on the servo, eg 1120 at the lead screw or 224 ipm MAX! to get more speed, you either need to decrease the reduction ration (assuming the servo would still have enough power to move the system at cutting force), or change servo’s/ power supply.

Hope I have done my math properly:})

[tauscnc]

Hey Bubba,

Thanks for the reply and taking the time to look up the info I did not give

I like the math and while I did not check the numbers it does make sense. So 224 ipm seams to be the limit...I will set it at that and be more than happy.

At least I now have some reason for the numbers...thanks again!!!!
Better to run slower than to ruin a part.

taus
www.cuttingedgecnc.com

[ger21]

My guess as to the faults is you're power supply may be a little low on current. Just a guess, though.

[Bubba]

tauseef,
Glad to try and hope it helps solve your problem. There are many variables that go into the equation to be able to maximize a solution. This was just one of them.