I have read a lot of conflicting information on stepper motor drivers. I'm just doing a little project to close my curtains with a few pieces I've got lying around and while the stepper motor I have is almost up to the task it lacks a bit of torque. The stepper motor is the https://www.oyostepper.com/images/upload/File/17HS13-0404S-PG5.pdf .
I had the L293D which says it can give 600 mA per phase which I think might be limiting the torque and I've read its a bit old an inefficient now a days. I've read the SN754410 is a direct replacement but has some issues.
I've been looking at the pololu drivers mainly the A4988 and wonder if this would be suitable/better? or does anyone have any better recommendations for a stepper running at 12v 2 amps?
The A4988 stepper driver is superior to the L298 and 754110. The stepper that you linked is 0.4A per phase. If you get the A4988, be sure to set the coil current limit. The Pololu page on the A4988 has instructions for setting the current.
The stepper motor in the link in the Original Post has a current of 400mA and coil resistance of 30 ohms. I have some similar motors and they work fine with A4988 drivers.
Use the highest voltage you can within the limit for the A4988. I use an 18v laptop power supply.
jashcroft:
Thanks for the tip on coil current limit! In what way is it superior?
Its a stepper driver, not a DC motor driver. Steppers are current-driven, trying to drive them
with voltage means miserable performance (150rpm or so), whereas current drive will allow upto
2000+rpm for some motors and supply voltage combinations.
Microstepping is a crucial feature for most applications of steppers, to prevent massive resonance
issues and allow quiet running.
Typical modern steppers are wound for low-inductance to enable high-speed operation, and low
inductance means very low winding resistance mandating a current driver. Typical winding
resistances for modern motors are 0.5 to 3 ohms.
Robin2:
The stepper motor in the link in the Original Post has a current of 400mA and coil resistance of 30 ohms. I have some similar motors and they work fine with A4988 drivers.
Use the highest voltage you can within the limit for the A4988. I use an 18v laptop power supply.
...R
The spec sheet does say that there's a 12v limit. Is running at a higher voltage ok?
jashcroft:
The spec sheet does say that there's a 12v limit.
All the 12v means is that with a 30ohm coil then by ohms law the current will be 12 / 30 = 0.4amps
It is the current (rather than the voltage) that is important for a stepper motor provided you use a stepper motor driver that can limit the current to protect the motor.
jashcroft:
The spec sheet does say that there's a 12v limit. Is running at a higher voltage ok?
Steppers are current driven, the specifications are current, resistance and inductance, voltage is irrelevant.
In a decent driver the supply is much higher than the resistance might suggest because its the inductance
that matters. Stepper drivers do current drive, and need more voltage at higher speeds to overcome the
winding inductance.
MarkT:
Steppers are current driven, the specifications are current, resistance and inductance, voltage is irrelevant.
In a decent driver the supply is much higher than the resistance might suggest because its the inductance
that matters. Stepper drivers do current drive, and need more voltage at higher speeds to overcome the
winding inductance.
Robin2:
All the 12v means is that with a 30ohm coil then by ohms law the current will be 12 / 30 = 0.4amps
It is the current (rather than the voltage) that is important for a stepper motor provided you use a stepper motor driver that can limit the current to protect the motor.
...R
Right that all makes sense, I'm not worried about speed and I have a 12V supply so I'll just stick with that. Thanks all for the help I've learnt a lot