AoA
i need to drive a large stepper motor for something i`m working on.....its considerably larger than the ones used in printers. takes 1.8° per step.
I've always used a ULN2003 ic to drive stepper motors but i've never driven something as large as this. i tried using ULN2003 to run it......it works but the ic gets very hot very quickly.
Anybody knows how to drive a big stepper motor????? Its really urgent 'coz i need to submit that something to somebody quite soon. Help me out guys.
One other thing.....the motor runs very slowly....takes 5 secs to complete one revolution. Do all stepper motors with small steps run that slow???
i tried increasing the number of steps but beyond 40 pulses per seconds the torque starts to gets really low.....i want to drive the motor at higher speed with substantial torque.
For optimum performance you must use current drive, insted of voltage drive.
because of inductance effect of motor winding, current [& torque] reduced in higher frequency.
Hey VSMVDD
do u know how to use these ic's. I mean i'm the worst of novices so i need help in this too. I've never driven a stepper with anything except darlingtons. How do u use these ic's. They look complex. I had a look at A3983 datasheet and couldn't get hold of anything though i guess they are supposed to be easy to use.
and
Hey Davood
If u can sketch a quick ckt using TIP120/121/122 to drive a six wire (2 common) motor and upload it i'll be really grateful.
look guys! i may be looking like an idiot to u right now but i'm desperate. Pleeeeeeeeeeease help me out.
and by the way
is a six wire motor bipolar or unipolar???
i think this question ought to clarify how weak i am at steppers!!!!!
a lot depends on how much current the stepper's coils draw. In general, bipolar transistors don't work well for higher current devices. Also, the answer depends on whether you have a bipolar or unipolar stepper (4 wires or more than 4 wires). Check this site for a lot of open source controller designs: https://pminmo.com/ There are a number of good ones there.
Note that to get more power, you should go to a higher voltage than on the label. This is ok if you keep the current at the rated level. There are 2 ways to do this: power resistors or PWM (chopping). PWM is much better. You can often go to 10X the voltage rating with no ill effect and a lot more torque.