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#127521 - 08/13/01 01:47 PM Audible Hertz
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
I have a new term " Hertz Vibration" that referes to the hum , noise, or other audible vibration heard from electrical gear.

note previuous thread; http://electrical-contractor.net/ubb/Forum2/HTML/000235.html

I don't know if the term is valid, or if so, the noise measurable ( I beleive ballasts have a sound rating) or how this side effect is produced or anything else....
cranium firmly imbeded in large intestine here...please feel free to call in the jaws of life if needed..

I have had the opportunity to be working in a panel yes, live and hear breakers buzzing under a load, some i have held my finger on and altered the noise level
were's that dutch boy when ya need im'

If this is indeed a bona-fide phenomenon, i am curious as to the details, if i have just been gulible i'll go buy more lottery tickets...


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#127522 - 08/13/01 04:41 PM Re: Audible Hertz
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
All kidding aside...

Are the CB's loose? (Like the old GE, they had problems) Even with a tight connection on the buss, older GE type breakers were loose enough to buzz under load... Got a bad rep from 'em, but have improved their product dramatically, in my opinion.

Is the vibration at 60 hertz?

The reason I ask, the Xformer for the music festval had a buzz at 120 hertz without any load (for those that don't know me, I'm a musician, trust me) which would be the first harmonic (wouldn't it?) I found that odd, and there was some hum on the sound system too, but at 60 hertz. (all sound was on one buss)

Most 60 cycle related vibration I've run into is usually at the 60 hertz fundamental frequency, the usual fluoros, dimmers, Xformers, etc.

I've heard breakers buzz under overcurrent situations right before they trip. Always when exceeding the rating of the OCPD, not under normal operation other than the GE's mentioned before, and they were giving 80%+ of their rated ampacity.

I think Bill has the right idea about it being similar to the whipping effect the filament in a bulb may experience.

Am I close?
_________________________
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#127523 - 08/14/01 05:18 AM Re: Audible Hertz
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Sparky,

I passed the Question along to a Product Safety Engineering Newsgroup I belong to.

I'll post any relavant responses.

So far:
 Quote:

>>sounds like a bad rental car experience<<
(I just got that one!)

>>It's likely a term used to describe the mechanical vibrations that you hear in a magnetic circuit breaker as the current it is carrying increases past its trip current. I've heard this noise, but not the term "Hertz vibration". However the name makes sense - the vibration would be at line frequency.<<

>>Must be something like "line buzz".
Happened at a place where we used a lot
of transfomers. If the transformer wasn't enamalled correctly, there'd be a loose winding that would buzz with the line frequncy.<<

>>The problem with overheard remarks is that you don't know if what is reported is a complete phrase or not. In this case, for example, there would be no mystery if the word 'sixty' occurred before the reported phrase.<<

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#127524 - 08/14/01 04:59 PM Re: Audible Hertz
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
hmm;
The notion that the sound created could be realted to physical movement make me nervous..
That would mean something is loose right?

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#127525 - 08/14/01 05:24 PM Re: Audible Hertz
gpowellpec Offline
Member

Registered: 12/06/00
Posts: 128
Loc: Irving, Tx USA
I did a Google search on "hertz vibration" and got sites where the term is used in reference to magnetic vibrations of the earth and vibrations of towers. Maybe the guy was getting his terminology crossed if he was talking about electrical.

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#127526 - 08/14/01 05:37 PM Re: Audible Hertz
Anonymous
Unregistered


>The notion that the sound created could be related to physical movement
Sound is a physical movement created by physical movement.

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#127527 - 08/15/01 03:37 PM Re: Audible Hertz
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Another Response on the subject:

 Quote:
I found quite a lot of references via Google, to 'Hertzian Vibration.' A lot of them made reference to contact closure types of equipment. By inference, it seems to be used in relation to low-frequency mechanical vibration.


Still sounds like a stupid bit of pseudo jargon to me. Like 'Hourly time' or 'Gallonic volume.' It's just wrong.


Sparky,

Can you think of a way to make sound without vibration?

Bill

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#127528 - 08/15/01 06:12 PM Re: Audible Hertz
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
no, not really

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