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plz atlist read this one time. L297 And L298 bepolar stepper motor driver.

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sizala

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hi friends , thankx for reading my this post.

my problem is =
**broken link removed**

i am using the driver which is in the datasheet of l298. i am using it with 24v 20amp bettery(bcoz that is a good power supply). and i am applying 2.34V to Vref , and the sense resistors value is 0.4/5W. it means that my motors are running at 0.98 amp. my stepper motor is 20KG/CM 1amp bipolar.

but the problem is = stepper motor is not going more then 150 Rpm. it doesn't matter if i use half or full step, in runs 150rpm in both modes.

so, plz plz plz plz help me to solve this problem. i want to increase the speed of my motor from 150 to at-list 300 rpm. i will be really thankful to you all.

(i think there is some problem with the chopper rate(i read it from some other online forum that chopper rate can effect stepper motors performance).
i am curently using the same resistors and capacitors as the data sheet is showing.= 3.3nf capacitor,22k resistor, the 470uf25V capacitor.)

plz plz plz plz plz plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz help me ..(i am controlling this driver form Ubuntu EMC2)
 
What frequency are you using for the clock on pin 18 of the L297? This is what determins the speed of the motor.

Assuming a 200 step/revolution motor-

200 steps x 300 rpm / 60 seconds in a minute = 1,000 Hz frequency
 
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Have you measured stepmotor terminals using a scope? Maybe there is something wrong with your oscillator.

What EXACTLY happens when the motors doesn't gain more speed?
 
Grossel , no i didn't measured stepmotor terminals by a scope bcoz i dont have a scope. and yes i am trying to say the same thing that "there is something wrong with my OSCillator ( pin 16 on L297), but i dont know which resistor and capacitor to use in osc to get more speed. And what EXACTLY happens is = when i run the motor at 150 rpm( 150rpm *200 stes rev. / 60 seconds = 500 Hz) the motor runes very well (with good torque), But when i try to run the motor at more then 160 rpm (from any computer software emc2, mach3, kcam) it just stats vibrating ( the driver is giving power to the motor but the motor is not able to run that much fast, so it is just vibrating ).


Shortbus, i am using a computer's parallel port for l297's pin 18, and yes my motor is 200 step/revolution.

so, guyz if you know that hoy to change the OSC pins Hz then plz let me know about it, And is that true that with more Hz the motor will run fast?

AND yes yes, i just forgot to tell you that = the motor is runing at 150 rpm in both half and full step mode. if i try to go at 160-1000 rpm in both modes then i face the same problem . so i thing that there is surely some problem with the OSC on L297.
 
i am running the motor 24v,
i dont have a idea about the resistance you are talking about (my motors are correctly running with out any kind of load)
yes my motor is a NEMA square style . https://www.circuitspecialists.com/products/full/8929.jpg my stepper motor looks like this.
yes i tried with the both "with ramp up" and with out any kind of ramp. but i does not make any difference.

and i didn't got you on the "chopper oscillator"... one guy was saying that the oscillator can effect the speed and torque, is that true?
and if yes then who to change the chopper oscillator to get a bit more speed?
 
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The resistance/friction I was talking about is how hard it is to move what ever axis, X,Y,Z on your machine. I assume a CNC machine, because your using Mach3 or EMC2.

The chopper oscillator is what controls the amount of current sent to the motor. If its not correct your motor will suffer, or not create enough torque. The link in my last post is the application notes for the L297. It tells you how to figure out the external components you need to make the L297 work right with your motor.

Read this link to understand more about steppers and drives. Jones on Stepping Motors
 
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