Loseing torque

[grahamshere]

Hey folks, Help! I,m losing torque , I'm running the 425's 3 axis,I,m using a pent 4, 2000 mhz mach3, using 8 tpi 4 start drive screws. My verf is set at 3.60 on all axis. I lowered the speeds from 200 ipm to 20 imp, every thing runs fine until I apply a little pressure to the gantry and that's when they stop or lose steps, I have 3 fans hooked up to the drives, the motors stay warm not hot.I did notice when I use my game pad to move my machine around I lose torque with out applying any pressure. Don't know if that would be a clue to whats happening. oh the drivers are set at 1/8 steps. and wish to leave them at that. Hope to here from some one thanks. Graham

[grahamshere]

Forgot I made some dampeners as well that did help some with the speed.

Graham

[grahamshere]

With verf's at 3.60 should'nt my motors run hot? there only slightly warm and that's running for a few hrs, I'm wondering if my multi meter is giving me a right reading.

[ger21]

No, they don't get hot because you're running them at 2.5amps, and they're rated at 2.8amps (guessing). Also, you're running them at a far lower voltage than they are capable of running at.

Back to your original question. Did they just start running poorly, or have you had this problem all along? Is 20ipm all you can reliably achieve, even with the dampers?

[grahamshere]

Thanks for the reply ger, I've had them running a lot faster than 20 ipm,I'm 8 tpi 4 start screws. I just finished rebuilding the gantry and started running the machine, I would run it at 140 imp with out a problem before the rebuild, now all 3 axis stall at lower speeds. I can move all the drive screws by hand so I,m sure there's no binding.I,m not sure if my meter is reading the verf right or not, I used my equus dig meter on a 1.5 v battery and it shows 1.7 v then I check with my analog and it showed 1.3 v but I may be reading that wrong, not sure how to read analog. thanks for helping

[ger21]

I'd make sure you're getting the correct voltage from the power supply, and double check the VREF settings.

[grahamshere]

OK ill check both and see what happens. thanks mate.

[grahamshere]

Ok I checked the power supply and it 24 volts, so that's right.I rechecked the verfs with both digital meter and analog, dig say 3.60, analog says 3.45, how do I check to see which is right? I checked the power supply volts with both meters and they both say 24 v so why would they both be so diff with the verf. I checked a 1.5 volt battery and the dig say 1.6 the analog say 1.4, there used batteries , could the driver blow if I went .15 over the recommended 3.6 in case the digital meter was right?

[ger21]

I'd leave it where it's at, don't risk setting it any higher. Try measuring the voltage with all the axis moving and see if it's still at 24V. Has anything else changed from when it worked?

[grahamshere]

Hmmm no I dont think anything has changed, how do I move all axis at the same time to check volts? Do you think the video card might have anything to do with it? its the same one, never changed it.nvida , this is weird, it,s sound like verf prob to me, the faster the speed the less the torque . but with these screws I should not have any speed problems at all. Graham

[ger21]

My guess is very unlikely that it's the video card. Just write some simple g-code that moves all the axis at once (preferably as fast as possible) and check the voltage while it's running.

[grahamshere]

I checked it it stayed at 24 volts, I have the motors disconnected so I hope it dose not matter. I asked around the neighbors if any one had a dig multimeter , not one has one, wish there was a way to check if they were correct or not.