HI Sound Level of Dry Type Transformer

135 db? That "sounds" a little much.

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

That sounds like an insane increase in the SPL.

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

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.

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.

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

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.

Is this aluminum or copper winding transformer?

CU/CU

Did you contact the manufacturer?.

Yes: but,they did't respond!!

<...respond...>

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

Are the laminations loose? vibrating?

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

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.

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

...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?

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.

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

Dear Mr.Progressive,

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

DHAYANANDHAN.S

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? ?

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

--JMM

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.

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

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

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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