could a 3 phase servo run clockwise only???

[patriciooholegu]

Hello people.
The last month i got a nice 3 phase brushless servo motor branded Kokusan Denki from a photocopier machine.
by searching on the web i found nothing at all about the motor, not any reference, not even about main IC used on the electronic board.
Rear stuff.
But last week, by pure look somebody of my country have the same motor and offered to send it to my for free, so im going to have 2 of this.
I will love to use does on a small cnc lathe im building.
The brand is, as y say, kokusan denki
Model apears to be TA0318.
It uses two IC's : SLA6023 (Oh, worst datasheet ever, dont send my that) and KA60228 (dip 30 format).

Here is the picture of the motor:
http://mundotronic.com.ar/foro/download/file.php?id=40

The problem im having, to make the long story short, is that this weekend grave it and plug it to a proper power supply and by a few test, was able to make it run on one direction, but not the other, no matter wath i did.

If you look at the picture, you will see that there are 5 wires to the motor:
Red - 24 volts
Green - Ground
Yellow - 5 volts
First blue, near to yellow - ?????
Second blue, far from yellow - ?????

Now, this motor tooke my attention because of the 2 signal cables on it. meaning: big size motor, build in electronic, obvius 3 wires for power, and only 2 extra ones, and in my imagination those should be for step dir connection. Could that be more easy?

well, it is not.

Wen i start measuring things i notice that the fist blue (Lets call it A) it was some type of ground, and the second blue (Lets call it B) was +5.

- If i connect A to B the motor runs clockwise
- If i connect A to ground the motor runs...again, clockwise (wen i do this wile measuring B, this drops voltage to zero)
- If i connect B to anything, noting happens.
If i connect A and B to ground the motor runs clockwise.

Im starting to think that may be this motor will not run at all to the other side.
Maybe they make it that way.
But at the same time im thinking "May they put this, for clockwise rotation only, instead of a simple dc motor?"
"They spend more on this fancy servo, so i should be thinking that is able to run both directions? "
Any suggestions?

Oh, wen the motor run, it is about 3-5 turns per second, and because of the lovely torque and gear reduction, it became almost unstoppable i may say.
So , if the factory make it to run both directions, im strongly tempted to use this two fellas for my project

[PBr]

Hi,

I think you won't be able to use this with cnc. The SLA chip is a transistor array, it just drives the 3 coils in the motor.
That chip in DIP30 package is the brain of the motor, probably a microcontroller, or some special ic.
You said it's from a copy machine, i think it can run only at constant speed, and very likely just in ine direction. you coul try to apply +5V at inputs through a 1k resistor to see if it changes the direction.
I think there are some hall sensors mounted too, they are needed to keep constant rpm.
The only one option that i'm aware of is to build your own controller (replace
the KA60228 chip).

PB

[patriciooholegu]

Originally Posted by PBr Hi, I think you won't be able to use this with cnc. The SLA chip is a transistor array, it just drives the 3 coils in the motor. That chip in DIP30 package is the brain of the motor, probably a microcontroller, or some special ic. You said it's from a copy machine, i think it can run only at constant speed, and very likely just in ine direction. you coul try to apply +5V at inputs through a 1k resistor to see if it changes the direction. I think there are some hall sensors mounted too, they are needed to keep constant rpm. The only one option that i'm aware of is to build your own controller (replace the KA60228 chip). PB

Thanks for the answer dude. Fast and clear.
Sadly, i want to think it runs like i want (Meaning like a suitable servo for CNC use), but im starting to believe that it doesn't.
Wen you suggest to apply +5 and 1k resistor you are talking about active low signals?
well, may be the fact that it runs wen connected to ground is confirming that.

but the question it is logical: Do this guys will use this more expensive motor for the simple task to run on one direction only?
Should i stuck on my hope that if there is a 3 phase servo is not ONLY to play the same job that any cheap dc motor will do just fine?

[patriciooholegu]

Control device for brushless motor and control method therefor

Dude, check this out.
It is some kind of explanation about a system driving for 3 phase motors specially made it for Kokusan Denky.
This is the second time i ended up reading something about patents web sites!
It suggest something like "Rotation angle" and all things like that.
i will read it this night and see what happens.
No matter which is the answer (It is able to run both directions or not, it is able to run at variable speeds or not) i will post the results to make a first statement about the subject.
Chears.

[PBr]

Originally Posted by patriciooholegu Control device for brushless motor and control method therefor Dude, check this out. It is some kind of explanation about a system driving for 3 phase motors specially made it for Kokusan Denky. This is the second time i ended up reading something about patents web sites! It suggest something like "Rotation angle" and all things like that. i will read it this night and see what happens. No matter which is the answer (It is able to run both directions or not, it is able to run at variable speeds or not) i will post the results to make a first statement about the subject. Chears.

Thanks for the document, interresting reading.
I think, that in aspect of reliability are the brushless motors the best option. And they are really easy to control if you have some know-how
The possibility to cotrol the speed is minimal, but there's a chance to change the direction. It depends on what was this motor mounted on.

[navyfalcon]

Ever think about changing the chip ?
Check with chip manufactures, they may be able to solve the problem
Tell them the motor information and see if they can get it to go both directions and vary the speed. One chip is the controller and the other is for power or driver. You may need to do some minor wiring changes. Use a chip socket to ease the changes.
hope this helps
falcon