resolver mechanical phasing

Hi.

I have a 1326AB servo motor and its resolver is out of tune.
How is the procedure of mechanical manual phasing in Allen Bradley?
Is that V+ W- and sine wave null? Or what?

Regards.

welcome to the forum.

please explain what you mean by out of tune?

does the servo home when you tell it to?
when you tell the servo to go forward, does it go forward?
does it go in reverse when you tell it to?

in my opinion,
if it homes, goes forward, and goes reverse when you tell it to, the servo is working, you have mechanical issues. that's been my experience.

james

Thanks for replying James
No, I mean it does not go any direction.
This mechanical adjustment of phase alignment I read about it in some forums.
I think it is different from brand to brand or from encoder to encoder, or even one kind of resolver to other kind, did you heard about it?
Regards
James

This is a problem we solved years ago. We just added a rotational offset.

Dear Peter
What do you mean exactly by adding a rotational offset?
Regards
James

To the best of my knowledge AB has never published this information. At least I have never seen it floating around out there.

What drive are you using the motor with?

Keith

Keith
It is a kinetix drive.
Does it make any difference? And how?
Isn't a right documentation of the motor (you say before replacing the unhealthy resolver) enough for gaining of this kind of information?
Regard
James

An instance

For your information here is what Kollmorgen manual on "AKM® Servo Motor Selection Guide" (page 54) states:

"Resolver Alignment
With positive DC current into phase W and out of phase V (U floats)
the resolver is aligned to electrical ±5 counts. ie. Voltage S1-S3
set to null voltage S2-S4 max in phase with reference (R1-R2)."

Regards
James

Originally posted by James Ross:

Does it make any difference? And how?

Click to expand...

It can. Some drives are designed to automatically determine the feedback device offset, much like what Peter Nachtwey indicated. If the drive had that capability you wouldn't need to specifically phase the resolver. The drive would calculate the offset and move on with live. Resolver phasing was only really a physical requirement with analog drives. Once you have a digital drive requiring mechanical resolver phasing is just laziness. Depending on the Kinetix drive (300 / 350 / 6500 / 5700) there may be a function in the commissioning section that will calculate an offset for you.

Originally posted by James Ross:

Isn't a right documentation of the motor (you say before replacing the unhealthy resolver) enough for gaining of this kind of information?

Click to expand...

I'm not sure what you are saying here. I can take it two ways. If you are saying that you could have powered the motor yourself and measured the resolver feedback independent of the drive, yes you could. That would be a way to do it. If you are saying that the motor manual should contain the information on resolver mechanical phasing, that is only true if the motor manufacturer doesn't want to profit from your pain. Rockwell is basically requiring you to return the motor if the resolver fails. They generally run pretty closed. To be fair, there are ways to incorrectly mechanically phase a resolver that will cause the motor to take off at ludicrous speed. So it may also have an element of CYA.

Keith

Yes I mean I powering the motor by myself and measuring the resolver feedback independent of the drive. In my case, I have't access to drive for factorial reasons. what I said was that if you force to replace the feedback for some reason (not only defectivness). You have to document it by one of the six combination of U, V, W phases and positive/negative DC current. Wouldn't be helpful?
Regards
James

You are correct, especially in the case of AB motors where there is no mechanical phasing information available. You would have to take a known good motor, apply a voltage to some phase combination and measure the resolver feedback. In the case of doing it on your own, you could experiment with phase combinations until you get the one that provides the easiest to repeat resolver signal. But that really doesn't help you now.

Keith

Dear Kaite
The benefit of these forums is to share the experiences.
Maybe someone has this experience, or even someone find a document regard to AB motors and put it here.
Regards
James