hi am using SY57STH76-2804A stepper motor , which datasheet rating is
3.2v , 2.8A and Coil resistance 1.13Ohms .
The motor driver should implement constant current operation, maximum current is rated 2.8 A.
Just use fixed PWM duty cycle to get proper current.
A more simple and very crude way to do this is to fit external resistors to each winding.
If its driven with 12v and you want 2.8 amps, then total resistance needs to be 4.285 ohms.
The stepper already has 1.13 ohms, so add a 3.15 ohm resistor.
3R3 would be about right.
That's a huge 26 watts of power dissipation which really makes it impractical, but it is one possible solution.
Not if you use a 3R3 resistor.agree.... ! But am driving with 12v Source and motor rating is 3.2v ,,, will it damage?
That's not funny, man! You will reduce efficency 5 times. 2.8A * 20V will give 56W power lost on each!A more simple and very crude way to do this is to fit external resistors to each winding.
Just take a PWM frequency 10 times higher than expected step time. For example, if you planing to use 1ms step time, 1kHz per step, use 10kHz or higher PWM frequency. I suppose, 1/10 duty cycle will be good enought. But this is actual only for 'on hold' static mode. For movement PWM duty cycle have to be calculated according constand current law. But if you not planing to use variable frequency, just find a good value for duty cycle that gives you expected force and current. It can be lower than maximum rating shown on sticker.for driving bipolar stepper mototr ,we wrer using pulsed signed on A, A+ ,B, B+ terminal , then how can i make again PWM on this ? can you please draw a simple wave form for half drive signal with PWM ?
Just to safe the motor from overcurrent the max duty cycle is: (raw estimation)I suppose, 1/10 duty cycle will be good enought.
My calculations for 24VJust to safe the motor from overcurrent the max duty cycle is: (raw estimation)
Motor_voltage / Supply_voltage = 3.2V /12V = 0.266 = 27%.
That's not funny, man! You will reduce efficency 5 times. 2.8A * 20V will give 56W power lost on each!
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Just take a PWM frequency 10 times higher than expected step time. For example, if you planing to use 1ms step time, 1kHz per step, use 10kHz or higher PWM frequency. I suppose, 1/10 duty cycle will be good enought. But this is actual only for 'on hold' static mode. For movement PWM duty cycle have to be calculated according constand current law. But if you not planing to use variable frequency, just find a good value for duty cycle that gives you expected force and current. It can be lower than maximum rating shown on sticker.
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