Bipolar stepper motor

Look up the website for your micro manufacturer, they often have application notes. I'd think this is a standard app'.

What micro are you using... Zilog have tons of app' notes.

Del

I've a problem in design I don't know what to use what should I use and from where to start.I want practical design something can be used

I read about H-bridge but I read that it is not practical and my requirement is high rating(12A and 300 V)

I suggest you start by trying to drive a lower power motor first... say 1amp

The app' notes I mentioned often have circuit diagrams too...or get onto the motor manufacturer for app' circuits.

If you really have no electronics experience you need to learn with something much simpler.

This is not a suitable 'first project'.

Maybe a simple DC motor (at 1amp) and an H bridge would be a reasonable start point.

Good luck

Del

Del is right!

I don`t understand your requirements - 12A and 300V seems to be able to vaporize your motor.

I`ve seen motors with about 85Nm and they only draw less than 3A at very much lower voltages. Seams that there are some dimensions wrong - or am I ??

Regards Uwe

The high voltage is necessary to get the motor current up high enough in a very short time - which is what you have to do to drive a stepper fast.

I have worked with H switches, switching instantaneous 40 amps to a PCB motor, I never had the impression that this was even near the limit....or anything unusual.....

A well designed H switch, should not give problems....

I'll tell you

I know that I should use power mosfet in H-bridge and use bootstrap and use the micro to give the signal

and get that the mosfet with rating double the req. due to start current

but I search for any experince that guides me and gives tips

Try going to this site, scroll down to the section called Datenblätter:, and download l297ds.pdf & l298ds.pdf (they are in English!). The L297 is a step motor control chip, and the L298 is a dual H bridge. (There are no doubt plenty of other sites where you can get the data - this is just the first one I found).

This combo will get you up to 2A/phase, which is a good start and will let you work on the control side without too many BANGS.

Once you get that all working, you can replace the L298 with discrete high power MOSFETs - you can more-or-less copy the internal bridge circuit straight from the datasheet.

Good luck.

thanks john

I know these chips but they can only drive motor has 2A/ph

my req is to have 12A/ph

Since there are people here taking the time and trouble to give you some advice, please have the courtesy to read what they have written, and don't fire off replies which clearly indicate that you cannot be bothered.

I don't mind helping, but I will not be messed around.

Sorry but I didn't mean to be uncourteous. but maybe my words cheated me

I repeat my apology

and sorry for wasting your time John

If this is for self education, start small.

If this for a real project, start small.

If you are not trying to learn programming, try Allegro drivers, you will get integrated drivers with esternal mosfets. Only step and direction is required.

Aslo, start small and understand the various properties for the small motor and calculate for the larger one.

The step sequence will be the same as your large motor, but the smoke less dense and less costly if you make a timing mistake.

12A/300V?

Judas Priest, son!

If you're doing this for your own edification/educational purposes, I strongly suggest you start small. You can buy small steppers and driver ICs cheap for same amount of education you'll gain. Bigger is not better here.

If you're doing this professionally (ie, for pay), I strongly suggest you buy an appropriately-sized stepper motor driver/controller off-the-shelf. It will be far
cheaper than the cost of your time and materials (including those you burn up enroute) - and your customer's/client's/employer's patience.

Sorry to rain on your parade, Zaz, but (in a manner of speaking) you really should learn how to build a boat before attempting to build an aircraft carrier.

My middle name should be DIY. I stripped the internet of about 1000 pages of info investigating stepper motor drivers. etc. Only to realize that although it is easy for anybody to get a stepper motor stepping a serious application deserves investing into a good off the shelve solution.

We went for Galil controllers, After the amazing result seen (the machine moves at 4-6 times the speed I could get with NO strain) I must recommend that.

In the documentation (somewhere) there is some MOSFET drivers of 4A and more.

There are some steppers with intergrated drivers. Maybe you can google.

You should have mentioned what I consider the most important feature of Galil: ease of programming.

I have a mental block against ladder logic: Galil's system is pretty easy and extremely flexible. Good support too!

Good call, Hendrik and Dkwarner. For my part I've used Galil's products in a number of applications including a 5-axis eucentric stage for an electron microscope, an experimental ion detector for a mass spectrometer, and in a world-class research telescope. The latter used a 2 HP servomotor (not a stepper in this case) to position the 5-ton telescope in azimuth to within a few arcseconds' accuracy. Galil's products are very easy to use as controllers go, IMHO. No complaints here.

...and since you mention servos, I've made essentially identical 5-axis machines, 3 with steppers and 1 with servos. Other than a few lines of setup, the programs are identical.

Both types of machine work well. I had a lot of trouble with the servos until I added gearboxes to get the required position control at very low speed; that solved the problem.

Do you have more info about the different about the Step motor and servo motor on your application. I believe It would be quite a lesson for everyone here.

You Bet!

I've been using steppers for about 25 years. For the first few applications, I wrote BASIC programs that sent on-off signals to discrete transistors to drive 1 Amp or smaller stepper motors. At that time I was teaching Physics, Electronics, and Computer Science; the applications were educational. The first one I recall used a single stepper motor to rotate loudspeakers, while a microphone recorded the output, thereby producing a polar graph of the angular response of the speakers. I retired from teaching about 12 years ago, and shortly thereafter started working on my current job, where some of my duties involve designing and building automated cutting and welding machines. (It's great! I get to combine my knowledge of physics, electronics, and machining all in one project).

Once I started to build industrial machines, I switched to off-the-shelf driver boards, and learned about micro-stepping (where instead of just switching magnets on and off, the current is adjusted from zero to full current in steps). Micro-stepping gives much finer positional control, and is quieter than full or half-stepping. The controllers I'm using have 1/64 micro-stepping, which means that a 200 steps-per-revolution motor can essentially be controlled to 1/12,800 of a revolution. The actual precision isn't quite that good, but it is way better than 1/200 of a rev! The fact that the current increases in little steps instead of sudden on and off is what makes the motors much quieter than full-stepping.

All my current machines use size 23 (2.3 inch square mounting plate) and size 34 motors. Most of them are very slow speed; the size 23 motors drive rollers of various kinds directly, with a speed pot that can manually control the speed from zero to about 60 RPM. Most of the size 34 motors have gear and/or belt speed reduction, with rollers twice as big, so their maximum speed is about 30 RPM, with the same linear speed. I also have some driving lead screws for X-Y Table control.

Many people kept telling me that servos are better, so I finally decided to try a set. The Galil controllers make the switch relatively easy; as I said, the programs are essentially identical for steppers and servos. Size 23 servo motors mount exactly the same as size 23 steppers, so at first I just swapped servos for steppers, and of course changed drivers. But it turns out that servos don't like low speeds. I had all kinds of problems trying to get the servos 'tuned'. After MUCH frustration, I added 10:1 speed reducers, and voilá - it works fine.

The servo system is quieter, and I like quiet! But it is significantly more expensive, especially when I had to add a speed reducer at each axis to get it to work reliably. The feedback loop of a servo theoretically means the machine knows when there is an error, and that should be good. But in practice, when operators (or whoever) don't maintain good lubrication, both systems can have problems.

Obviously I'm biased, having a fairly long experience with steppers and a much shorter experience ( a couple of years) with servos. For my applications, I prefer the steppers: on the other hand I wouldn't want a CNC milling machine that used steppers!

Hope this is of some help... You're welcome to ask specific questions.

Dick

I had good experiences with drivers from Applied Motion.

I a recent demo I saw their Anti-resonance and torque ripple smoothing features. It makes the steppers even quieter than microstepping alone.

That's what I've been using! (Hadn't heard about the anti-resonance!).

It is not some useless feature. Without resonance, you have more usefull torque an can go faster. The demo was quite impressive (Well just a motor turning, I must be a nerd).

The engineer's name is Eric Rice from their Chicago office.

Just like to add a quick word about the position feedback - I use steppers almost exclusively (a few servos and DC motors here and there). In any app where it's vital to have correct positioning (e.g. instrument calibration to NAMAS standards) I use position encoders (either rotary or linear) directly coupled to the driven part of the system. I generally use Allen-Bradley PLC's to control the motors and monitor the feedback, though I've also used Parker "intelligent" drives.

Step motors are everywhere this days, the tiny ones with gear has been used for instrument gauges on cars, boats, printers, the bigger one has been used on CNC machines. For tiny ones it can be drive directly by microcontrollers if the current is less than 20 mA. Otherwise a power interface has to be implement to provide sufficient current to the motors.

I use Stepper Motors since 1972. Earlier switching with 4x7 segment LED display driver with output of segment 'e' exact for unipolar or bipolar stepper motor. It is crude but excellent operation. Require circuit, inform me.

Presently I use Fatek PLC for stepper motor drive, you can visit their site for detail.

One of the project I prepared is 3 axis, 3 stepper motors, having over 120 cycles/min. That is, all three motors moves one by one withing 0.5 sec and completes their operation. With servos, it may not be possible.

Use IC TIP 127 or equivelent to drive directly from your microcontroller, else add 2N3055 for over 2 amp. per phase of stepper motor.

Find out SGS's Motion Control book. It has excellent description of several type of stepper motor drives, right from 0.5 amp to almost 8 amp / phase.