# What is it? CXCII

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• posted on August 12, 2007, 1:51 am

You first tune it for maximum sensitivity to the fequency in question, then you shift the angles and compare the maximum swing of the reed. This lets you determine in which axis the vibration at that frequency is at a maximum, and thus what is the likely componenet contributing to the vibration, so you can work on balancing it.
Enjoy,         DoN.
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• posted on August 12, 2007, 6:25 pm

That is an inertial balance. Its for the purpose of measuring the inertial mass of an object.
http://www.physics.umd.edu/lecdem/services/demos/demosg1/g1-55.htm
The large brass screw near the bottom changes the pendulum arm length. The weight at the top can be altered to increase the weight (hence the numbered slots in the box).
What it's measuring - I don't know.
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• posted on August 13, 2007, 3:46 am

I had agreed in another branch of this thread that it was not for measuring electrical frequency -- but the mechanical frequencies will be related to the electrical power frequency assuming an induction motor instead of a series or parallel wound DC or universal motor.

That is a rather different device -- for demonstrating principles in a physics lab. This device which we are discussing looks more like something to use in the field.

It is measuring the amount of vibration at a selected frequency along a selected axis -- for the purpose of identifying the sources of the vibration and eliminating or at least minimizing them, one at a time. You select a frequency, determine along which axis it is strongest, and work on balancing a device rotating at the proper RPM to produce that frequency and oriented to produce the vibration along that particular axis (that is -- perpedicular to the axis of rotation).
Not sure how much we will be able to follow this newsgroup for a while, given that it appears to be under attack by massive cross-posting to/from sci.crypt. I've set my killfile to eliminate those, but there is bound to be a lot of discussion about that -- plus probably cross-posting attacks from elsewhere as well.
Enjoy,         DoN.
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Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
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• posted on August 13, 2007, 9:02 pm

Sounds like a good description of it, I went ahead and put this on the answer page, I like it better than what I had there.

To everyone at RCM: feel free to join us on one of the other groups on Thursday if you want to post some answers or read some comments on next week's post. Hopefully things will clear up soon.
Rob
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• posted on August 14, 2007, 1:53 am
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I agree with the functional description. My questions are: 1. Why was the Edison screw base used as an interface?, and 2. Are there any other known uses of the Edison screw base for anything other than light bulbs, heaters, and other electrical connections? We may never know, but it is sure interesting.
Don Young
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• posted on August 14, 2007, 10:21 pm
E Z Peaces wrote:

Ft. Rucker, Al. in the early '70s: They found a dashboard for a '66 GTO, a case of motor oil, a propane torch and other car parts along with two tool boxes. They just looked at each other, then at me. One started to say something, then shook his head and walked out, followed buy the other inspector. One of them muttered, Damn Weathervision section! as he walked down the hall to the next room. ;) Another inspection was a group from the Pentagon, inspecting command companies. he told my captain that i had the cleanest and neatest room he'd seen on over a dozen bases and asked who's room it was. When he heard I was just an E2 with a private room he got upset, then changed his mind. "Anyone who can keep a room like this deserves to keep it". I didn't argue. I was on call at odd hours, on separate rations, and the idiots I had shared a four man room with were slobs, and at least one thief. I was the only one in that barracks with Cable TV in my room, too. :)
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