uncertainty of speed regulation

[jrddjr]

I'm going to drive an spindel by a Dc motor and speed servo controller.I need uncertainty of speed regulation in one turn of motor shaft at the steady state running.I heard that it is function of the motor, not of the speed controller.Is this true? If it is true where I found a report?

Thank you

 

[DickDV]

The drive and the motor together form a system that can regulate speed. It takes both.

Varying levels of speed error detection and response time will determine just how closely the motor shaft speed is regulated.

Generally, the shaft speed will need to be measured with an encoder or tachometer with the actual speed signal sent back to the drive for processing.

 

[ScottyUK]

Are you considering the changes in angular velocity which within one revolution? Torque ripple of the motor may be a consideration, as will the nature of the load itself. It is a tricky parameter to measure - why do you need this?

Could you clarify what you are trying to measure or predict?


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I don't suffer from insanity. I enjoy it...

 

[jrddjr]

Exactly, I want to calculate the measurment uncertainty of a measuring device. So I need the amount of angular velocity ripple in one turn revelution of motor shaft. the running Torque is about Max. 40Nmm and the load variation during running speed only is due to variation of frictional forces of a pair small radial ball bearing and forces due to misalignment of cuplled shaft (by a fexible cupling).

Also some speed controller manufacture wrote some statements as below:

"phase locked loop techniques yield 0.001% accuracy and regulation" or "0.05 per cent speed regulation"

I want to know the exactly defination of such statements.
Thank you

 

[IRstuff]

Still not clear what you are trying to do. If you're trying to calibrate a measurement system, you should be comparing against another instrument with higher accuracy.

You can't possibly "calculate" the angular velocity ripple, since you have, apparently, zero data about the motor you're trying to characterize. Any unaccounted for drag will drastically alter the ripple.

TTFN

 

[jrddjr]

Thanks to DickDV, ScottyUK, TTFN & nbucska for replies.

A better description of my problem is followed:
I want to predict the erorr probablity of a measuring device.
An reasonable estimation of angular velocity ripple in one turn revelution of typical motor shaft which reported in literature is sufficient.

Thank you

 

[ScottyUK]

I wonder if you can adapt a wow-&-flutter meter to make a direct measurement? The motor shaft would need some means of providing a signal input - maybe from a tacho generator? Those instruments are getting hard to find but are cheap because no one wants them in this digital age.

If you haven't met the term before, the link will give a little background:

http://en.wikipedia.org/wiki/Wow_and_flutter_measurement

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I don't suffer from insanity. I enjoy it...