Stepper Motor: Pictures of Internals

[ww_kayak]

I'm sure most of the people on this forum have an understanding of these motors, but I thought I'd post some pics, for newbs like me, of an Epson Stylus motor that I took apart. Having these to look at made it easier to understand all of the stepper motor articles I've been reading. I'm sure there are similar pictures on the site already, but sometimes there is just too much info !-) Anyway, I just wanted to start to contribute :-)

[InspirationTool]

I was wondering how the stack of plates worked in the equation.

Thanks!

-Jeff

[jeffs555]

Thanks for the good pictures. You probably know, but for others who don't, disassembling a stepper motor is a bad idea if you plan to use it again. Removing the rotor from the stator can demagnetize it and greatly reduce the available torque.

As for the plates; most motors, transformers, and iron core inductors are built up from thin plates insulated from each other. This reduces the eddy current losses which consume power and generate heat.

[rally.sport]

hi
well ive takne mine apart today to sort out a problem
in my motors (large industrial ones) they have 4 segments on the centre shaft and they seem to be getting pulled along it until they all of the central drive peg, all 4 move along together but once one falls off the drive stops
any ideas anyone?
thanks
james

[thkoutsidthebox]

Hi kayak,

Great first contribution. I've been drifting around this forum for almost a year now and have never seen the inside of a stepper, until now!

What are the ridges/grooves shown in your 7th picture for? (Attached below)

[ww_kayak]

Ya Jeff, I wasn't too worried about hurting it, I didn't really plan on using it for anything (too wimpy), but it was a good learning experience. I was able to write(basically copy) a small program and hook it up to my Linux box's parallel port and got it to turn in wave, full, and half step mode. Simple, yet... "WOW, THAT'S COOL!"

Originally Posted by thkoutsidthebox What are the ridges/grooves shown in your 7th picture for?

Like I said, I'm a newb, but I assume they localize the magnetic fields, or maybe simply bring them closer in those critical locations. I'm sure somebody here would know better than I.

[pastera]

The teeth create local maxima/minima allowing the motor to act as if it had many more poles than physically present. If you look closely hte teeth are offset from each other such that the teeth on the rotor can only align with a single set on the stator.

Aaron

[FPV_GTp]

hi

Kayak nice pics , as i have asked and search several times in here has anyone any idea what a stepper motor or servo motor looks like inside

do you have more pics ?

cheers

[ww_kayak]

So, where does the offset between the upper and lower stators(disks?) fit into the equation? Does that only come into play in certain modes? (half-step, micro, ...)

FPV, that's the only motor I have, but I love to take pics, so if I find anything else of interst I'll rip it apart and take pics