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Topic: Geared Stepper Motor (Read 43318 times) previous topic - next topic

Stolfa

sbright33,

   Sorry, I haven't checked this forum in a while.  Please contact me with an offline message with your address and I'll send you a 4075+ motor.

Stolfa

pebert

Hi

What happened to this issue?

I just ended up in trouble with my 28BYJ-48 and realized that I have the same issue as some of you.

Did you ever managed to find a motor with an even number of steps per revolution?


Stolfa

Sbright33,

   I think you had received one of my 28BYJ stepper motors last summer.  Any luck at checking it's steps/rev?

Dave

ozgr

#33
Apr 16, 2014, 02:21 pm Last Edit: Apr 16, 2014, 02:27 pm by ozgr Reason: 1
hi everyone, I've recently bought 28BYJ-48 5V DC stepper motor from china for my school project. I chose this motor only because it's cheap.

The gear ratio doesn't have to be exactly 64:1 for me, because I won't use them where the precision is important. Nevertheless because of sheer curiosity, I opened up one of them and count the gears. It was a painstaking process thanks to teeny tiny plastic teeth.
I took some photos to use zoom option and save my eyes but my average digital camera doesn't come up with nice photos.

So I double checked the numbers and found out exact same numbers with Stolfa;

Main rotor has 9 teeth and connected to 32-11 gear then 9-22 --> 10-26 and finally 31.

(32*22*26*31)/(9*11*9*10) = 63.68395062 (405:25792)  which is NOT acceptable for precise applications. I don't know why the manufacturer uses these gears instead of using some others to achive 1:64 ratio. Is it difficult to find or produce plastic gears with different teeth numbers?

Now I understand why quality stepper motors are expensive. At least they meet the spesifications manufacturers provide.

Hellolife

Hello,

I don't understand why this motor wouldn't be a good help for precision projects. First of all, reductors are based on "mutually prime" gears, to distribute wear evenly. But, more, there is NO ideal reduction factor: by exemple, in watchmaking, what i f i want to cut a 47 teeth gear ?
One can, i think, approach any angle with desired accuracy with this step-motor, eventually by running it more than one "complete" turn. I shall calculate the number of steps and turns with this goal of minimum error, modulo 2*pi, or modulo 64*63.75 etc

Sorry for my poor english.
Regards

MarkT



(32*22*26*31)/(9*11*9*10) = 63.68395062 (405:25792)  which is NOT acceptable for precise applications. I don't know why the manufacturer uses these gears instead of using some others to achive 1:64 ratio. Is it difficult to find or produce plastic gears with different teeth numbers?


The motor is made specifically for steering vanes inside
vehicle air-conditioning units, its not designed to be very precise
(the backlash is large, for instance), its designed to be easy to drive from
a 5V control circuit and just powerful enough to do the job.  The large
gear ratio is to increase the torque to resist forces on the vanes more
than anything.

Its very cheap because its made in 10^8 quantities probably.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

steinie44

I think, one thing that has been completely overlooked in this thread is the frequency of your Arduino. If anyone has programmed a millis clock will know the problem you run into. Not all Arduinos run at exactly the same speed, close, but not exact.

MarkT

The Duemilanova came as standard with a 16MHz quartz crystal, so it could be
used to determine accurate times and frequencies.

The Uno comes with a cheap 16MHz ceramic resonator, only accurate to 0.5% or
something like that.   My Uno had space to solder on a quartz crystal in place of
the resonator so I did that, as sometimes you want accurate time.

This is a bit of a step back IMO.  I hope the recent versions of the Uno allow such
a repair job to be performed...
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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