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# Stepper motor high speed(rpm)? Answered

I need a high speed (rpm) stepper motor but i don't exactly know where and what to look for. I have recently assembled this project for a laser harp :
https://www.instructables.com/id/Frameless-Laser-Harp/?ALLSTEPS
I have finished everything but the stepper motor parts.
The stepper motor I had ( 28BYJ-48 – 5V) had a high torque but was far too slow to split the beams properly. My stepper motor shopping has left me more confused than when i started.
Where can I find a quick stepper motor that can run on say 5-24 volts? It seems the stats rarely include speed or rpm.
Thank you for any help in the matter.

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## Discussions

Just to spread out what Steve says: The stepper by itself is just a series of magnets and cols, the speed is controlled by the frequency of the applied current from the controller.

As you increase speed the current in each coil has less time to peak and you will find that to get high speeds you need to have higher currents/voltage (they are of course connected.

Any stepper motor can turn fast - 10,000 RPM are easily possible - The model aircraft brush less motor is a special stepper motor and can reach 30 - 50,000+ RPM off load. but at perhaps 40 amps+ to give both the speed and torque.

You need to look further into how a stepper motor works - there are numerous o nline reference works -and perhaps review if you really need a stepper.

Irrespective of Motor specification How we can tell that all motors can run upto 10,000 RPM easily. there will be the specification like rated current, phase current, rated voltage and phase voltage for the efficient operaion right?

I don't see why they used a stepper, they could have put an indexing disc on the motor, and turned the laser on and off as needed.

This is deviating a bit from the initial question. But I do not know what is meant by using an indexing disc for this particular project?

Use a constantly spinning, high speed DC motor. Put a mirror or two on it, but also put an index mark on it that can tell the computer exactly how fast the motor is spinning, and where it is in space.

All you need to do then is switch the laser on and off when the mirror is in the right place.

In the computer, when the index mark is seen, start a timer, when its seen again stop it. Take the time reading and decide how many beams you want (6, over 30 degrees, say)

If the time for the rotation is T, then every degree of rotation takes T/360 seconds. So, if you want N beams in theta degrees, you need to wait Theta x T/360/N seconds, then turn the laser on, wait, say 2T/360, then turn the beam off and wait again.

Mm I tend to agree. people tend to use what is familiar or available. I don't think the stepper is the optimal answer here.

The maximum speed is a function of the controllers ability to switch the motor coils. What are you using ?

I am using an arduino uno and a uln2003 chip to control the 28BYJ-48 stepper motor at its suggested 5 volts. The adapter i'm using powers the stepper at 1 amp. From the helpful info that rickharris gave it sounds like I need to increase the amperage?