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Author Topic: Locked motors  (Read 199 times)

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Locked motors
« on: July 29, 2019, 08:15:38 PM »
Although I registered awhile ago, I haven't been able to play with my CNC.  Quick background: I bought a cheap Chinese CNC years ago, with the promise that it worked over USB.  Well, that was a lie.  To get it to work, it said I needed a hacked version of Mach3.  I don't like the sound of that, so I bought a Gecko unit to act as a controller, and bought new motors to boot. 
I really don't know what I'm doing, so don't judge too harshly.  At one point, I was able to get the motors to jog using the arrow keys.  I was never able to load G code or get the computer to even make a circle or square on its own.  Now, when I turn on the computer, the motors, which I can spin by hand when the power is off, get locked up and make a squealing noise.  The jog control arrows don't work.  Can anyone point me in the right direction, or let me know what I have to tell you to help me?

Thanks

Phil
Re: Locked motors
« Reply #1 on: July 29, 2019, 08:44:11 PM »
Hi,
when you power up the motors should lock up. What that is telling you that the drivers are enabled an powered up.
The resistance you feel is called  holding torque.

If now the driver receive pulses from Mach the motors should move. If they squeal then the pulse stream was faster than the
drivers/motors can accelerate and you have created a stall, the squealing sounds bad but its not harmful to the motors for
short duration periods.

What have you tuned your motors to? ( That is steps/unit, max velocity and acceleration on the motor tuning pages).
If you have tuned too aggressively the motors will stall. The trick is to start with low velocity and acceleration and work
up until the onset of loss of steps or a stall. Then backoff by 25%.

Craig

My wife left with my best friend...
     and I miss him!
Re: Locked motors
« Reply #2 on: July 31, 2019, 06:42:49 PM »
Here are my settings:
Steps per: 2000
Velocity: 120
Accel: 4
G's: 0.0103607
Step Pulse: 0
Dir Puls: 0
I can turn the jog feature on and off from the keyboard, but the arrow keys don't move the motors.  I also get a little bit of an electrical smell.

Thanks
Re: Locked motors
« Reply #3 on: July 31, 2019, 07:31:09 PM »
Hi,
I'm guessing you are using inches as your native unit?

With 2000 step/inch and a max velocity of 120 inch/min will require Mach produce step pulses at:

(2000 x 120)/60 =4000 pulses/sec. That should be within Machs capabilities but are your motors capable?

May I suggest try a low max velocity to start with, say 40 inch/min.

The electrical smell does not sound good. Do you have a circuit diagram of how the motors are wired to the
drivers? I suspect you have a problem there.

Craig
My wife left with my best friend...
     and I miss him!
Re: Locked motors
« Reply #4 on: August 22, 2019, 01:35:59 PM »
Here are my settings:
Step Pulse: 0
Dir Puls: 0
Step Pulse of 0 microseconds won't do anything...
I think the default is usually
Step Pulse: 2
Dir Puls: 2

Marsha
Re: Locked motors
« Reply #5 on: August 28, 2019, 03:54:10 AM »
Here are my settings:
Step MyPrepaidBalance´╗┐ Pulse: 0
Dir Puls: 0
Step Pulse of 0 microseconds won't do anything...
I think the default is usually
Step Pulse: 2
Dir Puls: 2

Marsha

If now the driver receive pulses from Mach the motors should move. If they squeal then the pulse stream was faster than the
drivers/motors can accelerate and you have created a stall, the squealing sounds bad but its not harmful to the motors for
short duration periods.

What have you tuned your motors to? ( That is steps/unit, max velocity and acceleration on the motor tuning pages).
If you have tuned too aggressively the motors will stall