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stepper motor acceleration problem

S

sudheervemana

Jan 1, 1970
0
Hi all,

I am developing stepper motor control board in the devicenet
network using TI Dsp controller and National Motor driver rated with 3
amps continuous current.
When i am testing my application in the position mode by giving some
parameters like target position ,target velocity,target acceleration
and target deceleration ,my 2 phase stepper motor is spinning with
some constant velocity,even when i am changing the velocity in my
timer period register in order to achieve the target accleration,it
was rotating with constant velocity.I am able to see the changes in
the period register value,but even then it was not able to
accelerate,what could be the reason,please help me to achieve my motor
to the target acceleration.The profile i am using was trapezoidal with
the microstepping mode,and the motor specs are 2 phase and with max 3
amp current can carry.I am driving only 2 amp to the motor coils where
chopping is done in the driver using some sense resistors.

Do i need to drive 3 amps instead of 2 amps to the coil
for the motor with 3 amps max current,why because my motor was not
able to achieve the target acceleration.What will happen if i drive 2
amp current to the coil ,even my motor withstands for 3amps
current,Does the motor does not accelerate.Please give me your
suggestions regarding the problem,i am able to see the changes in the
Period register value .


Regards,
Sudheervemana.
 
T

Tim Wescott

Jan 1, 1970
0
sudheervemana said:
Hi all,

I am developing stepper motor control board in the devicenet
network using TI Dsp controller and National Motor driver rated with 3
amps continuous current.
When i am testing my application in the position mode by giving some
parameters like target position ,target velocity,target acceleration
and target deceleration ,my 2 phase stepper motor is spinning with
some constant velocity,even when i am changing the velocity in my
timer period register in order to achieve the target accleration,it
was rotating with constant velocity.I am able to see the changes in
the period register value,but even then it was not able to
accelerate,what could be the reason,please help me to achieve my motor
to the target acceleration.The profile i am using was trapezoidal with
the microstepping mode,and the motor specs are 2 phase and with max 3
amp current can carry.I am driving only 2 amp to the motor coils where
chopping is done in the driver using some sense resistors.

Do i need to drive 3 amps instead of 2 amps to the coil
for the motor with 3 amps max current,why because my motor was not
able to achieve the target acceleration.What will happen if i drive 2
amp current to the coil ,even my motor withstands for 3amps
current,Does the motor does not accelerate.Please give me your
suggestions regarding the problem,i am able to see the changes in the
Period register value .


Regards,
Sudheervemana.

Look at the motor driving voltage with an oscilloscope, and see if the
steps to the motor go at the speed that you expect.

A stepper is a synchronous motor, and if you feed it drive at a higher
frequency than it can follow it will slip, and its average torque will
go to nearly zero.
 
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