[tastefulasever]

Has anyone had any experience building stepper motors?

There's tons of information on stepper formulae, theory, basics, etc., but I haven't found any DIY attempts.

Thiis site, http://www.aerodesign.de/peter/2001/...index_eng.html was very cool, and the closest thing I've yet seen to a DIY stepper motor blog.

I'll continue to search, because I'd like to try my hand at building some motors, learning from my inevitable mistakes, then building some decent motors.

[Xerxes]

Interesting project! But I'm suspicious about performance of DIY stepper. I'd rather try to build a servo motor instead.. wait.. actually I'we been buiding those things in our shop.

We build three phase permanent magnet axial flux generators/motors (see image). This design gives 1.7 kW power at 250 rpm.

More info (sorry, Finnish only):
http://www.kylmatec.com/windg.php

[pminmo]

xerxes,
Any way to tranlsate your website to english?

Phil

[Xerxes]

Translated version is coming when I have enough time to do it.

Here is picture of principle. Multiple rotors/stators can be stacked to get greater power.

[mdreitzusa]

tastefulasever,
i found this artical you might be interested in.
http://www.flyelectric.ukgateway.net/machin.htm
it tells how to make brushless motors.

[mdreitzusa]

just found another one for the lrk-torquemax
http://forums.radiocontrolzone.com/s...threadid=84200
looks like it would make a good spindle motor.might make one myself to test the posibilities. :banana:

[erwak]

Well I see this is and old post but Im new here and Im really interested in this subject.

ok. here is a link to a site with some basic info and nice pics.

http://www.phys.unsw.edu.au/hsc/hsc/...c_motors7.html

If anyone find more info please please contact me.

[AMITSHARMA2904]

hi guys,

is there any one who is having a link for how to make stepper motors????????????

[vger]

I mused one time about building a linear stepper using a large quantity of disk magnets. If you took the disk magnets and stacked them in a tube with like poles facing each other then surrounded the tube with multiple coils seperated with washer shapped metal disks and got the spacing all worked out...... I'm sure it's been done somewhere.

[Motus]

There are two facets to understanding what the needs and requirements are and neither are that simple. When building a stepper motor you have to understand the magnetic theory pretty well. Some stepper motors only use 1/2 the potential magnetic energy. I did see a 100% magnetically confined stepper motor that used both the north and the south poles of each magnet, and it was also over 100 poles. Could it be used in a 4 pole stepper probably.

It comes down to controlling the motor. PIC controllers are all fine and good on paper but when you get right down to it, unless you are very good at assembler, with most of the routines, the timings will not be precise enough to do micro-stepping where you get the most torque. So why go through all that effort. Additionally you have to understand gate charge and what kind of drivers you need and how efficient the circuit needs to be. It is just not that easy.

Unless you are interested in building a motor that currently cannot be found off the shelf is one thing, but then again there is a good reason for that.
1. Controlling the potential energy of a magnetic circuit is where this is at.
Large motors need magnets so large they are dangerous in unskilled hands. I think this is where the industry has drawn the line.
2. The stepper motors need balanced magnets meaning they have to be matched otherwise a dominant magnet with sufficient flux from the electronic circuit can ruin the other magnets that are weaker in their BH curves.
3. Eddy current heat is another magnet killer.

All in all it takes engineers who spend most of their time thinking about all of this with vast engineering budgets to creating new designs in stepper motors. Sorry as some of the other posts have said you are better off building servo motors.

[emadcnc]

many thanx

[Motus]

Maybe my post went too far in engineering terms and too far in general. I do stand by from what I said with the exception of N-S capture of the magnetic circuit. If the magnet is fully captured, it is the coil circuits that tend to be unipolar with the other pole leaking.

I have a motor design that I am trying for years to put together. If anyone here is willing to collaborate and has a milling machine what I have is a small 4" dia rotor holding the magnets, an axle, and only needing the case with the stator and with horseshoe type of steel plates. I was able to get the motor to run with only one turn, but the current requirements even at 800 amps were insufficient. The paper this motor is based on says one needs 2000 amps and I do not know where anyone gets that kind of current. It was interesting that only 2.5 volts were impressed on the armature at this current. I went through 10 very expensive International Rectifier Hex Fets rated at 1500 amps before I saw that the bonding methods they used were too small to handle any current imbalances. Even IR was stymied. The result of solder ball types of transistors will help but one still needs paralleling at very high currents which also means matching and common heat-sinks.

All doable but again where does the current come from? One thing I thought was capacitive discharge and a 5 -1 charge time. That would mean having several of these rotors in parallel and only needing 500 amps charge with 2500 amps delivered to the stator. Again an engineering feet. The formula for torque is based in B^2 in Tesla's. That means running close to a magnets (Neodymium) capacity in B. But until one gets over 1 Tesla nothing really happens. Again it is the reason for the ultra high currents. 000 gauge wire can handle 600 amps. Trains carry several of these in parallel. A train also runs at 2500 VDC to the motor. Most trains have over 1M HP. One big reason that diesel is still needed as batteries would be wiped out in about 30 minutes of use.

The purpose of the motor is to establish a hub design that would fit in a wheel of a car or truck. 25 KW is needed for a passenger car per wheel. The largest force in a car is climbing up a hill. At zero inclination there is no force needed if acceleration is 0. The only thing that comes into play then are the 15 to 15 hp requirements to overcome wind and tire resistances. In a train it gets even better because the wheel resistances are only in the turns and as long as the tracks are in great shape and the wheels hardened and true a train needs very little energy at speed on a level surface etc...

For this motor design, at 25kW and at 25 volts that is till 1000 amps. Again the capacitive discharge design would work and would only need someone good at choosing capacitors that can take the discharges and last as long as the batteries.

Anyone interested in collaborating? In these times needing more innovation in electric car technology, this motor can play a large roll and this one would be the largest stepper motors ever built. I can email interested people private confidential drawings and specs. Sorry no public forum stuff only discussions. (group)

[rowbare]

Before you go putting something as heavy as a drive motor in a vehicle wheel, you might do well to research "unsprung weight". You will quickly see that it isn't such a good idea...

In a nutshell, a vehicle with that much weight on a wheel will have awful dynamics and will handle very poorly. Reducing unsprung weight is one of the reasons that formula one cars use inboard disk brakes (cooling being another).

At the very least, for this project to be practical, you will have to move the motors inboard. It is an interesting research exercise though.

bob

[Motus]

Before you go putting something as heavy as a drive motor in a vehicle wheel, you might do well to research "unsprung weight". You will quickly see that it isn't such a good idea...

In a nutshell, a vehicle with that much weight on a wheel will have awful dynamics and will handle very poorly. Reducing unsprung weight is one of the reasons that formula one cars use inboard disk brakes (cooling being another).

At the very least, for this project to be practical, you will have to move the motors inboard. It is an interesting research exercise though.

bob

Yes I agree with that assertion. The biggest losses are seen in translating the forces into another axis. Moving the motors inboard can still avoid that. One trans-axle is only 30% efficient due to the fluid losses in the lubricants.

The research on this is very practical. The design packs all the magnetic potential energy in at the manufacturing stage and that is very hard to do. Then it is merely getting enough flux energy into the sheaves to oppose the magnetic poles and time them very accurately in generating huge amounts of kinetic energy into the axle, just like any other 4 pole stepper motor. The difference here is 100 plus poles and doubled to prevent coging which becomes more acute as the torque goes up.