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HI Sound Level of Dry Type Transformer

04/29/2013 3:48 PM

Possible cause, reasons of suddenly increased the sound leval as measured 135db in Dry type distribution transformer 11kv/380v, 2500KVA that is in service since couple of years & it was working well, sound level was normal- less then 80db as per log book record shows.

While the Incoming line voltage,Load & ambient temperature are in allowable or normal condition.

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#1

Re: HI Sound level of Dry type transformer.

04/29/2013 4:06 PM

135 db? That "sounds" a little much.

Check it again. What is the loading on the secondary?

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#2

Re: HI Sound level of Dry type transformer.

04/29/2013 4:10 PM

That sounds like an insane increase in the SPL.

I'd say a power quality analysis is due in short order...as in, ASAP!

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#3

Re: HI Sound level of Dry type transformer.

04/29/2013 4:18 PM

135 dB is jet aircraft loud.

I'd say it's a sure sign of impending boom for the transformer.

It takes a LOT of energy to produce 135 dB. You must have been wearing hearing protection, right?

Something's broken loose inside.

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#4

Re: HI Sound level of Dry type transformer.

04/29/2013 4:32 PM

Providing a SPL (Sound Pressure Level) reading without the distance from the source and the weighting scale/frequency band, doesn't give enough information.

Take the output of the meter and run it through a spectrum analyzer, if it's not the fundamental or some harmonic of the line frequency then there's something loose somewhere that's vibrating against the core, windings, or enclosure.

If it's the fundamental then a winding may be loose, an even harmonic then look at the core for a loose clamp or mounting structure, odd harmonic look at the load it's feeding, especially if it is terribly unbalanced and/or highly non-linear.

Has the physical environment around the enclosure changed? If so it's possible to set up a resonant condition and/or standing waves in the area which will greatly magnify the perceived sound. Moving the mike/meter around will allow you to see if this is the case.

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#5
In reply to #4

Re: HI Sound level of Dry type transformer.

04/29/2013 5:10 PM

Yeah...and like Lyn said...is there an F/A-18 nearby? They usually register about 110 dB in my driveway.

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#6
In reply to #4

Re: HI Sound level of Dry type transformer.

04/29/2013 5:38 PM

SPL is measured with a sound intensity probe, at the source.

But a db meter and an analyzer should give some indication. Your point is well taken about distance. Knowing the frequency would help, for sure.

Sound decays 3 dB for each doubling of the distance, I think, so the closer, the better.

Less reflected energy to deal with.

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#7

Re: HI Sound Level of Dry Type Transformer

04/29/2013 8:48 PM

Is this aluminum or copper winding transformer?

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#13
In reply to #7

Re: HI Sound Level of Dry Type Transformer

04/30/2013 9:56 AM

CU/CU

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#8

Re: HI Sound Level of Dry Type Transformer

04/29/2013 11:34 PM

Did you contact the manufacturer?.

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#15
In reply to #8

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:15 AM

Yes: but,they did't respond!!

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#22
In reply to #15

Re: HI Sound Level of Dry Type Transformer

04/30/2013 11:07 AM

<...respond...>

Make some telephone calls, then, and stop wasting time!

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#9

Re: HI Sound Level of Dry Type Transformer

04/29/2013 11:39 PM

Are the laminations loose? vibrating?

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#14
In reply to #9

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:00 AM

No sifnificant for core/lamination loose. Torqueing varification have been done but, not find any thing loose.

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#10

Re: HI Sound Level of Dry Type Transformer

04/30/2013 2:39 AM

If the increase in sound level has not been accompanied by some mechanical action, . . . then the sound level increase is due to the LOAD.

Most likely someone stuck a rectifier load on the transformer - drawing DC from the secondary. This will case saturation of the core and magetostriction will cause the excessive noise.

Measure the sound level withe the transformer unloaded - is it high as well? Return the loads , . . one-by-one and see which one causes the noise.

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#21
In reply to #10

Re: HI Sound Level of Dry Type Transformer

04/30/2013 11:04 AM

We will check for the second part of your ( rectifier load) & comeback.

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#11

Re: HI Sound Level of Dry Type Transformer

04/30/2013 3:04 AM

...and if it is one of the loads, then disconnecting each one in turn will identify which one it is. Has this been tried yet, and if not, why not?

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#12

Re: HI Sound Level of Dry Type Transformer

04/30/2013 8:41 AM

Can you safely check the amperage on the transformer input on all three phases? The transformer may have lost a phase internally on the primary. If the transformer is single phased, that could be the source of the noise.

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#16
In reply to #12

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:22 AM

As, earlier discussed that, Input & out put Voltage measurement P/P & P/N are Ok as per name plate Voltage rating.

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#17

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:42 AM

Dear Mr.Progressive,

My doubt is damaged/broken core. Pl. check this.

DHAYANANDHAN.S

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#19
In reply to #17

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:54 AM

Mr, Dhay.

We are have made a complete Physical Inspection for it ,but did not observed for any damagedor broken core.

Is there any specific test that can help us to trace the fault exactly? ?

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#24
In reply to #19

Re: HI Sound Level of Dry Type Transformer

04/30/2013 8:20 PM

One non-contact test would be an infra-red scan with a good camera, done by a qualified operator.

--JMM

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#18

Re: HI Sound Level of Dry Type Transformer

04/30/2013 10:45 AM

Has there been a recent significant decrease in load on the transformer, to the point that it has almost no load on it? Is the primary fed by underground cables that cover a long distance from the source? It could be ferroresonance, which can produce some pretty awful sounding noises from a transformer.

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#20
In reply to #18

Re: HI Sound Level of Dry Type Transformer

04/30/2013 11:01 AM

Yes,few days back there was very low load on it.

Yes, Primary fed by Underground cable but, short distance (around 50-Fts)

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#23

Re: HI Sound Level of Dry Type Transformer

04/30/2013 3:45 PM

If you haven't anything broken loose inside like lyn said, then revise feeding primary loose connetion to dicard ferrorresonance effect which produce high sound level in transformer

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cuba_pete (2); dhayanandhan (1); Grand Poobah (1); jmueller (1); juan J. Isdray (1); lyn (2); NAMINI (1); North of 60 (1); olehwi (1); PeterT (1); pnaban (1); Progressive (7); PWSlack (2); RAMConsult (1); WAWAUS (1)

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