MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > After Building the Beast - Operating , Troubleshooting and Maintenance > Troubleshooting
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #1  
Old Sat 02 January 2010, 19:22
lumberjack_jeff
Just call me: Jeff #31
 
Montesano, WA
United States of America
Motors are weak and run cool - setting up a "Leadshine" drive

I'm working through a couple of anomalous behaviors.

I have leadshine clone drivers and fulling steppers.



My power supply is delivering 52v. My drivers are set for 6a peak current.

My gantry frequently jumps the rails because one of my X steppers misses steps.

My cutting speeds are slow because of this. However, my steppers are barely lukewarm after a half-hour of operation.

I intend to reduce the x acceleration and (now that I've gotten an unrelated computer problem solved) increase the microstepping (I'm currently at half-stepping)

My question is about the motor temperature. If my steppers are not overheating, is it safe to set the peak current higher? (the driver's maximum is 8a)
Reply With Quote
  #2  
Old Sat 02 January 2010, 22:36
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Since you set the currents for 6A, I assume that you did wire the motors "parallel"?

Is your SW4 on the drive switched to "ON"? (in the off position, the output current is halved)
Reply With Quote
  #3  
Old Sun 03 January 2010, 06:21
javeria
Just call me: Irfan #33
 
Bangalore
India
Try connecting just one set of coils, motors might heat up - but there will be no loss of steps.
Reply With Quote
  #4  
Old Sun 03 January 2010, 09:42
lumberjack_jeff
Just call me: Jeff #31
 
Montesano, WA
United States of America
If memory serves, they're wired unipolar. When I indicated that the drivers are set for 6a, I meant 6a peak or 4.3a RMS. (1-0-1)

Is that right? I assumed the rated motor coil currents are RMS.

I should probably not be lazy, I should cut the shrink tube off the wire at the motor ends and verify the wiring scheme. I suffer from CRS.

And yes, sw4 is off: the idle current is halved after 10 sec of inactivity. I'll change that to "on" since motor heating is obviously not a problem.
Reply With Quote
  #5  
Old Sun 03 January 2010, 11:37
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The way I read their document, SW4 is not related to current reduction during inactivity (0.1 sec, not 10 sec). SW4 seems to be a total current reduction irrespective of the activity and this will explain your cool under-powered motors.

RMS vs Peak is very seldom used in specs for stepper motors, and strangely enough "duty cycle" is never discussed either. I suppose we should strictly be talking RMS - if we wanted to talk peak then we need to know how long the peaks are (duty cycle).
Reply With Quote
  #6  
Old Sun 03 January 2010, 13:56
lumberjack_jeff
Just call me: Jeff #31
 
Montesano, WA
United States of America
Thanks Gerald. I set SW4 to on and it does seem to help.

Or at least I was able to run a problematic program in its entirety without annoying crashing/banging noises, the motors did get warmer and the tool did return to zero.

I'm going to try higher micro stepping resolution next.
Reply With Quote
  #7  
Old Sun 03 January 2010, 22:17
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
The higher stepping resolution is probably the place to start. Remember to change change your "Steps per (inch?)" value in Motor Tuning. Suggest you go for 2000 steps per revolution, which will put you on a par with everyone using gecko's. (SW5/6/7 on, SW8 off).

This will allow slightly higher accelerations, and means you can tweak the whole of the motor tuning.

Then, lastly look at motor temperatures and current.
Reply With Quote
  #8  
Old Mon 04 January 2010, 07:08
lumberjack_jeff
Just call me: Jeff #31
 
Montesano, WA
United States of America
EMC has a function which measures computer latency. That latency plus the timings of the drives chosen serves as a speed limit of the installation. My computer has had a recurring intermittent latency which made me hesitant to go to really fine microstep resolution for fear that I'd exceed that speed limit and lose steps.

It seems that I've resolved that latency problem, so I changed to 2000 steps per revolution. What a difference, (in sound at least). Much smoother and quieter. My resolution is now 4800 steps/inch.

Due to a low corner speed combined with dinky pinions, I'm still limited to about 260 IPM though. I have some replacement pinions which will allow 320 IPM or so, but I haven't yet installed them.

Since resetting SW4, changing microsteps and increasing acceleration, my motor temps are about 45°c.

As always, thanks for your help Gerald.
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
QJ8060 Drive from CW-Motors Francois 701. Motor Drives 13 Tue 14 September 2010 12:31
All motors run fine then start chattering and loosing steps - interrupt in the PC KevinL Troubleshooting 24 Wed 14 October 2009 21:11
Duty Rating stepper motors - setting the drive current Gerald D Motors & their mountings 26 Tue 23 June 2009 05:07
Generic Aussie (Leadshine) Stepper Motors are they OK? Jama Motors & their mountings 5 Tue 23 December 2008 08:05
Motors do not move after initial setting up - Mach setups fabrica Troubleshooting 17 Fri 19 January 2007 01:04


All times are GMT -6. The time now is 01:59.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.