Why dimples on watr hour meters using aluminum damping disks?

Oct 07, 2010 10 Replies

All the aluminum disks used for a shaded pole motor and damper in energy meters that I have ever seen are dimplied instead of having smooth and flat surfaces. Why is that?



Bill


So you can see that it's turning.

It has something to do with the Eddie currents induced into it but I cannot remember the reason. Long way back in my training.

Bill

It is the last operation during their manufacture that work hardens the media, and flattens the surface to the die shape). The work hardening can change the hysteresis based heating of the disc, so it tends toward it homogenizing the forces placed across the disc.

It keeps them flat without requiring anodizing the soft alloy that gets used, which would screw up the magnetic properties.

It is like a network mesh of hard to toggle, easy to toggle lattice structures.

Stop being a goddamned full quoting, top posting retard, boy.

I was thinking along those lines, but have no knowledge that such thoughts are based upon reality.

The dimpling would cause dislocations in the aluminum to increase its resistivity. But the same can be achieved by alloys. At best, aluminum is slightly paramagnetic. I do not think work hardening will affect that much. It is the conductivity that is utilized to produce eddy currents to drive the disk and to damp its rotation.

Bill

Might be just that simple, but one cannot help but think that anyone needing it for that purpose has a few missing marbles. Mainly the two situated in the front of his skull.

"Eddie currents"?

And this top posting, inconsiderate idiot "plonks" us?

Bwuahahahahah!

Yeah... it was a long way back in something, dipshit.

Is it possible you could stick to the topic or does your ADHD medication need increasing, again?

And this top posting, inconsiderate idiot "plonks" us?

Bwuahahahahah!

Yeah... it was a long way back in something, dipshit.

Please explain why top posting is bad. I usually do not, but this time I am driven to be ornery.

Bill

Lattice defects, such as dislocations from cold working or impurities from impurities from alloying, will increase resistivity. To first order, the resistivity of the disk material is irrelevant as long as the resistivity is uniform. A high resistivity will lower the torque produced by the coils driving the disk. The higher resistivity will also reduce the damping torque from the damping magnet.

For me, all this is speculation. I do not KNOW why the dimpling is used.

Bill

Bottom posting confusion.

I did not write any of the following.

Lattice defects, such as dislocations from cold working or impurities from impurities from alloying, will increase resistivity. To first order, the resistivity of the disk material is irrelevant as long as the resistivity is uniform. A high resistivity will lower the torque produced by the coils driving the disk. The higher resistivity will also reduce the damping torque from the damping magnet.

For me, all this is speculation. I do not KNOW why the dimpling is used.

Bill

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