# LOUDLY buzzing transformers



## ssandoval

Has anyone had any experience with pad mtd transformers suddenly starting to buzz LOUDLY?; so loud in fact that two people can not hear each other speak in the same room.

I have had three XMFR's ( two 112.5 KVA and a 150KVA ) go bad in the last two years and another with the same symptoms about ten years ago.

They work fine; all measurements are good, everything has been tightened and checked, and the shipping bolts checked for proper post-install tightness per manufacturer spec. One key common factor; all are GE transformers. The previous dept supervisor's fix for these three was just to replace them but I can't believe that's the only alternative. Any thougnts anyone?


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## nakulak

get some earplugs and replace it when it blows up ?


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## ssandoval

Not an option... seven teachers, twenty kids each. I am the elect. supvr. for a large school school district with 47 campuses. I would rather try to figure out why these xfmr's are failing (why they start this loud constant buzzing to begin with). Anyone else with a real idea???


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## goose134

We had a similar problem on an existing transformer and it was recommended that we install isolation pads on the transformer feet. Didn't help much. If the only solution is to replace it, maybe try another brand? Our shop pretty much uses Square D exclusively, unless otherwise specified. I would be interested to find why some transformers are WAY louder than others.


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## ssandoval

10-4. So would I. With rergards to the pads, both the pads it rest on and the interior frame pads look fine. It almost seems like the core plates are causing this noise but the varnish looks great. I had two of my electricians open for me today; we turned it back on (covers off). Buzzing like crazy from somewhere inside the windings or core. All frame pinch bolts are tight. Just don't get it... At $3000 a pop I hate to keep replacing them just to get them to quit but I may not have a choice. It's driving the teachers/ kids nuts. Thanks for the input.


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## ampman

transformers hum because they dont know the words i know , iknow that bad


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## paul d.

take the top off and see if there are some kind of shipping brackets inside. maybe LOOSEN some bolts on the frame and see if the buzz changes. or call a REAL electrical contractor to come take a look at it. good luck. but it dont look good.


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## MDShunk

a motor shop can cook it and drench the windings in new varnish and quiet it right down. Works like a charm.


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## drsparky

Most of the noise comes from the plates vibrating. Are all the shipping bolts loose? Did you shim it with a level?


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## ssandoval

paul d. said:


> take the top off and see if there are some kind of shipping brackets inside. maybe LOOSEN some bolts on the frame and see if the buzz changes. or call a REAL electrical contractor to come take a look at it. good luck. but it dont look good.


 
Did you not READ my original post?? We did take the covers off ad first thing we checked were the shipping bolts. As for a "REAL" electrical contractor, none of our ILA's have a clue. Their fix is always the same, "change it out". I have engineers and designers at my disposal as well. I thought I would try here because I thought surely someone had run across this before. FYI, I am a union electrician with a Texas master license that I actually tested for, with 30 years in industrial, commercial and residential experience so I have been around the block at least twice... THANKS TO ALL who have posted real advice.


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## drsparky

Sorry for giving you any advice, I've been told "yes I loosend the all the shipping bolts" before and found they had missed the back ones. No need to get angry, we are here to help each other not get bitched at.


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## ssandoval

Dr. Sparky,

Actually my response was directed at Paul D, more so due to his comment with regards to getting a "real contractor". That's why I included his quote. My apologies to you. I considered your advice as a real attempt to help....

Also, great idea MDShunk, if it makes it to summer I might try that this time around.


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## paul d.

ssandoval said:


> Dr. Sparky,
> 
> Actually my response was directed at Paul D, more so due to his comment with regards to getting a "real contractor". That's why I included his quote. My apologies to you. I considered your advice as a real attempt to help....
> 
> Also, great idea MDShunk, if it makes it to summer I might try that this time around.


 i apologize for my wording. i meant the " real " to mean for you to consult someone with the right kind of expierence with those size x-fmrs. as in, not a residential electrician. anyways, PLEASE let us know how you handle th problem. again, GOOD LUCK!!!!!  PAUL


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## Mike_586

Have you tried contacting GE and getting on their case about it? I've never had to deal with GE, but I've had plenty of direct dealings with a few manufacturers over issues with their products over the years. Its a wasted exercise trying to deal with some companies, but most of them are usually pretty good about trying to solve problems with their products, once you figure out who you should be dealing with that is.


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## Zog

You said all measurements are good but what did you measure? Did you do a TTR test? Winding resistance and excitation test? What was you polarization index result?

There has not been any real info about this unit posted yet so there is no way to give you any real advice. I suggest you call a certified testing company that specializes in transformer testing beyond the "take off the covers and tighten the bolts" You can find a company that does this type of work and has the right test equipment at www.netaworld.org


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## nick

ssandoval said:


> Has anyone had any experience with pad mtd transformers suddenly starting to buzz LOUDLY?; so loud in fact that two people can not hear each other speak in the same room.
> 
> I have had three XMFR's ( two 112.5 KVA and a 150KVA ) go bad in the last two years and another with the same symptoms
> 
> Well yes we have !! Heres what we found GE has aluminum windings in transformers are your windings aluminum ? we had one job that had your 112.5 kva same issue when she was at a certain load she started to vibrate its your windings internal heat and lots of load current and poor windings meaning manufactured junk . The aluminum is rapped in parfin and polyurthane covering and insulation between coils but if its not percise in manufacture its going to be a vibrating nitemare and it will happen with copper also its more so with alu . these burn up due to insulation break down .
> 
> They should not make alu windings!!!
> 
> 
> 
> Heres one more that will effect transformers make them vibrate we do lots of new work and lots of transformers each year . paralled secondarys if when a electrician installs let say 500 mcm large wire and brings the secondarys in with no slack in connections meaning a tight or sloppy install you need play in termination to lug and transformer just as that rubber vibration pad give a little and shell not vibrate tight fit she makes sounds 60 cycle hum gets real loud when it becomes a tuning fork . take care We done a few but this is not a everyday thing  just once or twice in 35 years http://i611.photobucket.com/albums/tt195/stringking/IMG_0660.jpg


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## ce2two

I know a rewind shop that dips there motors in varnish 3 times no matter who the customer is , try to find a company, SQ.D or who ever that possibly dips there transformers multiple times more the the competition ...quality or quanity ....I believe varnish is an issue :thumbup:


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## micromind

I've had good luck with motor shops as well. If I can, I'll remove the core & coils from the case, but be careful. They're heavy, and easy to damage. 

To a motor shop, a 150 KVA transformer is not all that big. They heat it up, then dip it in varnish several times, and you have basically a new transformer. And much quieter!

Rob

P.S. If you're going to replace it, find out the load on it. Most likely, it can be replaced with a smaller (and quieter) unit.


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## Zog

Dont you guys ever test anything? Is this trrade to the point where we just replace things without any troubleshooting?


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## nick

Zog said:


> Dont you guys ever test anything? Is this trrade to the point where we just replace things without any troubleshooting?


 Well yes our company test every piece of equipment we install ?take care


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## Buddha In Babylon

hhhmmmm....sounds to me like you need to achieve the 88 miles per hour to generate the 1.21 gigawatts. Everytime my flux capacitor fails, i have the same problem with my hoverboard.
???


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## paul d.

Zog said:


> Dont you guys ever test anything? Is this trrade to the point where we just replace things without any troubleshooting?


 how do you " troubleshoot " a noisy x-fmr ? :001_huh: every noisy one i ever had we eventually replaced.


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## nick

Well Paul when you test for a living like Zog you kinda say test alot . But if ya install work everyday like us you call up GE and tell them to replace it they need to fix it not us . Its not making sound unless you turn it on ! megging is not going to tell you that winding packing and support insulators are not tight or not installed correctly .
Ratio check is not going to tell you nothing about sound problems .

But put a load on it and it might or might not it depends if its GE junk . 

Is there anyother test that i missed ? comments take care how do you test for noise before you install a transformer ? take care


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## Zog

OP said he has replaced 3 of these in 2 years and your advice is replace this one too. No one here thinks there is something causing these transformers to fail so quickly??


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## acmax

*If you know everything you need HELP*

Noise : Vibration : Torque :when there's noise level changes related to load you always check your install on the secondary.Also there are pad mats . Never used one but have seen them in schools.Can't say that will solve the problem but replacement is very expensive.30yrs never replaced one for noise........112.5 shouldn't be loader than blender running on medium making a good old fashioned milk shake.


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## nick

Well personally no i dont think anyone can burn up that many transformers in 2 years on one job . Not in my life time !

Only way i see burning up a transformer is load to breaker size meaning overloading the transformer . 

Like i said its real rare and its a factory issue guess i only look at things one sided as we only do new work so we never see repair or service work ever . 

But the op says hes a electrician so ya think he has looked at the normal process of the load and connections to that transformer . like balance load , voltage checks ,current study , ??? kinda thought he might have done that ? 


If its a school most transformer secondarys have a [200% neutral ]in the last 10 years or so that maybe a engineer who forgot that a school has lots of computers didnt calculate the feeders or lets say the proper size for the load . But if ones asking what we would do on a normal job yes i do a load study on that trans and find out why . 

But were not there and just given what input we have seen normally in our time its a bad transformer as our jobs are engineer by plans and specs only way its going bad is the transformer right from the factory in our scope of work . Take care be safe and call a electrician !


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## hogsmoss

my experience with GE has always been bad. last job I used GE service equipment, had 2 bad 1200 amp breakers that were shipped months apart from each other. also had a very loud 500kva xfmr. GE reps came out to deliver the new breakers and took a look at the xfmr, said they couldn't find any problems with the xfmr. the noise problem was ok since it was installed in a parking garage but the next week one of the new 1200amp breakers went bad and we also had 2 125A and 1 250A breaker go bad on the same service. GE was more than happy to replace them ,again, but man was it annoying.


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## davis9

Zog said:


> Dont you guys ever test anything? Is this trrade to the point where we just replace things without any troubleshooting?



How much would it cost to have your company come out and "test" for a possible problem with say a 112.5KVA x-former?

Tom


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## Pierre Belarge

ssandoval
I see you have not posted to this thread recently, hopefully you are still lurking, as there has been some good advice.

I of course, will add my 2cents.

1. contact the manufacturer for any help, they have a lot of experience from field calls and may have an answer for you, or at least a direction to go in.
2. have there been any changes to the loads since the last episode?
3. What is the temperature of the room they are in?
4. have you checked the running temperature over a period of time?
5. I am sure you have cleaned them during the PM. Is the environment they are in different than the standard location for Transformers - dust/dirt/cautics/ moisture/temperature, etc...
6. As Zog has mentioned, a testing company. If this has been a persistant issue, maybe it is time to find a company with experience in transformers for testing. Test equipment can find issues that our senses cannot.
7. Size of conductors - as mentioned, do the conductor allow for vibration?
8. is there other equipment in the location that may affect the transformers?
9. Again, as mentioned, is there a need for K-rated transformers?
10. have there been any faults or large short circuits in the secondary of the transformers? These events can warp windings and equipment, which may contribute towards the noise.

and
I like the idea of possibly dipping the windings, as heat/dust/overloads/faults can really shorten the life of the windings.


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## Zog

davis9 said:


> How much would it cost to have your company come out and "test" for a possible problem with say a 112.5KVA x-former?
> 
> Tom


Too much, based on travel. But call these guys, NETA certifed, very good group, as old friends of mine. A small unit like that wont take long but most testing companies have a minimum 4 hour service call, they could test several in that time, but if you only have 1 you will be stuck paying for 4 hours. If you have any ground grids, breakers, GFi's, or anything else have them test that also to fill in the time. 

*American Electrical Testing Co.
*PO Box 267
Canton, MA 02021-0267
Phone: (781) 821-0121
Fax: (781) 821-0771
Website: *www.99aetco.com*


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## paul d.

any of you guys ever bot a x-fmr off e-bay? they got LOTS o em there. surprised at the prices. and yes i know about shipping charges. maybe thats an option for the OP.


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## MDShunk

Zog said:


> Too much, based on travel. But call these guys, NETA certifed, very good group, as old friends of mine. A small unit like that wont take long but most testing companies have a minimum 4 hour service call, they could test several in that time, but if you only have 1 you will be stuck paying for 4 hours. If you have any ground grids, breakers, GFi's, or anything else have them test that also to fill in the time.
> 
> *American Electrical Testing Co.
> *PO Box 267
> Canton, MA 02021-0267
> Phone: (781) 821-0121
> Fax: (781) 821-0771
> Website: *www.99aetco.com*


I see that NETA has become a paid advertiser on this site. Pretty neat, I think. Of course, nobody likes advertising, but that's sorta how they keep the lights on here.


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## Zog

paul d. said:


> any of you guys ever bot a x-fmr off e-bay? they got LOTS o em there. surprised at the prices. and yes i know about shipping charges. maybe thats an option for the OP.


Be very careful, Ebay is a breeding ground form counterfit products, I was at a conference last week and UL's head anti counterfiting guy gave a seminar, EBAY was thier #1 concern for elctrical products. 

Also, rarely will your equipment be tested from an EBAY seller.


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## MDShunk

Zog said:


> Also, rarely will your equipment be tested from an EBAY seller.


Sometimes, this is not even a concern. I recently bought a few HMI's for such a good deal that I didn't really care if they were tested or not. If they didn't work, I could essentially **** can them and I wouldn't have lost much. I've bought NIB (new, in box) breakers that I could tell were actually never installed. I don't mind much that they were not tested. They were a smoking good deal. 

I used to have an office girl who's main job was to trawl eBay for stuff I use. She ended up quitting, but she saved me a ton of money (way more than she was paid). I have feelers out now for a replacement for that same job.


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## paul d.

Zog said:


> Be very careful, Ebay is a breeding ground form counterfit products, I was at a conference last week and UL's head anti counterfiting guy gave a seminar, EBAY was thier #1 concern for elctrical products.
> 
> Also, rarely will your equipment be tested from an EBAY seller.


 good point zog. most of those x-fmr's looked to be from used equipment dealers. i know we installed some used MCC few years ago from a co. that only dealt in re-cond stuff. it was owner supplied. it was good installation .


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## bobelectric

drsparky said:


> Most of the noise comes from the plates vibrating. Are all the shipping bolts loose? Did you shim it with a level?


 They all start squawking after a while.


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## bobelectric

Hit it with a hammer!


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## wildleg

what tests did get performed on the transformer, anyway ? (I'm guessing you amprobed it, but did you check the power quality or did you at least get someone to IR it ?) there's something fishy about losing that many


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## Zog

MDShunk said:


> Sometimes, this is not even a concern. I recently bought a few HMI's for such a good deal that I didn't really care if they were tested or not. If they didn't work, I could essentially **** can them and I wouldn't have lost much. I've bought NIB (new, in box) breakers that I could tell were actually never installed. I don't mind much that they were not tested. They were a smoking good deal.
> 
> I used to have an office girl who's main job was to trawl eBay for stuff I use. She ended up quitting, but she saved me a ton of money (way more than she was paid). I have feelers out now for a replacement for that same job.


Some day. one of those breakers will fail, and you will be liable for all damages and injuries. I have been involved in many court cases as an expert witness in equipment certification and testing. As the installeer you are the one who has the legal resposnibility to install safe, working equipment. You dont need to test a breaker you put in a home, but you do need to be buying from a reliable source like a major OEM for new or a PEARL member company for reconditioned. Buying off EBAY sets you up for recieving untested or counterfit equipment. You are rolling the dice with your EBAY games.


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## paul d.

sent a pm to the OP. he replied that the primary was tapped up on 460v at the factory 20 yrs. ago. he changed it to 480v tap. he said it solved MOST of the noise problem. paul


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## Magnettica

ampman said:


> transformers hum because they dont know the words i know , iknow that bad


That's a good one! :laughing:


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## electricalperson

he should probably hook up a PQA to the transformer to see what the electricity looks like. the transformer could be overloaded with harmonics and isnt Krated. an averaging clamp meter wont show harmonic loads


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## MMiller

I mainly deal with the size range of 20 MVA to 1200 MVA units but we just replace several PAs in some autotransformers due to a defect in their core. In short, bad design in the clamping frame which lead to loose core steel and reduced force on the pressure plates which apply clamping force to the windings. 

The ear mark to the problem was excessive noise and vibration under load while on the "odd" taps of the LTC (PA in series with the tap winding). This issue didn't show up at the factory tests due to the lack of load current in the test bay. This has since been resolved.

I don't know if they do a sound test on the pad mount units or not to be honest. Might be worth asking GE about...factory test reports should have come with the new unit. Doubt you'll see SFRA or Leakage Reactance in among them. Doble will come to site and run excitation for you but they are expensive to use.

to sum it up. I'd venture a guess at loose core steel and or windings. You may find someone to repress the windings but the cost may be that of a replacement unit.

just my two cents worth of guessing.

Mike


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## Voltech

Hate to dig up old posts but I didnt want to start a new topic on something that has already been discussed. If I need to start a new topic just let me know.

I have read every post on this thread and have tried everything other then getting someone who test x-formers out there.

Mine is a 75kva GE. WE have yet to put it under a load yet. The panel if feeds is for A/C units that have not been hooked up. I have already spoke with GE and they sent me another one and it makes the same noise. 

I also have a 45 kva right next to it that does not make any noise at all. I had to put my ear on it to see if it was on.


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## 10492

If I'm not mistaken, I think you can order a transformer with lower DB rating, they are just more little more expensive.


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## Zog

Voltech said:


> Mine is a 75kva GE. WE have yet to put it under a load yet. The panel if feeds is for A/C units that have not been hooked up. I have already spoke with GE and they sent me another one and it makes the same noise.
> 
> I also have a 45 kva right next to it that does not make any noise at all. I had to put my ear on it to see if it was on.


Shipping bolts removed? That is by far the most common thing. 



Voltech said:


> I have read every post on this thread and have tried everything other then getting someone who test x-formers out there.


That should have been the first thing you did.


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## Voltech

Zog said:


> That should have been the first thing you did.


I think that would be a waste of money without a load on it. GE sent me another one and covered cost and labor after my 1st call to them. Per my scope of work, everything is correct. I want this to be corrected and will work with my customers to correct it. Im just not going to dig very deep into my pocket for doing something per the plan. Here is what I have.


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## Zog

Again, shipping bolts/braces and loosening hardware on the isolation pad are the prime suspect here. Have you read the book that came with it?

*5.4 Audible Sound Sources​*The audible sound produced by transformers is due to the energizing of the core by the alternating voltage applied to the windings. This creates vibrations whose fundamental frequency is twice the frequency of the applied voltage. The audible sound will be present even under no load conditions. The vibrations producing audible sound can occur in the core, coil, mounting, housing, and in the conduit. The transmission of sound from the transformer can be by various media such as air, metal, concrete, wood or any
combination​​​​_. Amplification of audible sound can occur in a given area due to the presence of reflecting surfaces._​_
_​*CONTROL OF AUDIBLE SOUND SOURCES:​*​​​​Commercially available vibration isolators can be installed between the transformer and its mounting surface. This will reduce case vibration and compensate for slight unevenness of the mount. They should be sized for the appropriate loading at twice the fundamental frequency. To eliminate possible sound generation, the enclosure panel screws of the transformer housing must be tight and the housing must be securely fastened to the mounting surface. Care must be taken to ensure proper and tight installation of conduit. Flexible conduit is recommended.​
*
CONTROL OF AUDIBLE SOUND TRANSMISSION:​*​​​​Acoustical-absorbing material should be mounted on reflecting surfaces to reduce sound reflection and possible amplification. Transformers should be mounted on a firm support having as great a mass as possible. Vibration pads or properly designed isolation mounts under the transformer will reduce transmittal of sound. On generalpurpose transformers, neoprene rubber isolation pads isolate the core and coil assembly from the transformer enclosure. The isolation pads are located between the bottom core clamps and the base assembly. The isolation pads are tightened at the factory for shipment and must be loosened to allow the pad to expand prior to the unit being energized. Refer to enclosure assembly picture on last page for details.​
*​*​​​​Some circumstances that can cause high field readings are:​
·​​​​Higher than rated voltage being applied to transformer windings. Must be measured with a true RMS meter.​
·​​​​Isolation pad hardware was not adjusted to allow the pads to re-expand and/or shipping braces were not removed.​
·​​​​Transformer enclosure panels not properly tightened.​
·​​​​Improper installation of conduit.​
·​​​​Improper location of transformer. Mount the transformer as far away as possible from corners, walls or ceilings. Installing transformers near hard surfaces such as concrete walls will amplify the sound and may require the use of sound absorbing materials.​


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## RIVETER

Has anyone noticed that in the first page of this thread, pauld posted a few responses? All I am saying is that none of us know when we are moving on. Respect others as you would want them to respect you. That way, at least, you would be a GOOD memory.


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## Voltech

Zog said:


> Again, shipping bolts/braces and loosening hardware on the isolation pad are the prime suspect here. Have you read the book that came with it?


As for reading the book, No I didnt. But Im sure that I have removed all the shipping bolts and braces. We installed 3 like units that were all braced the same. Its just odd that this one unit is so loud. I will put card board on the walls and floor in the morning. My dad was a studio musician, I kinda understand an acoustical effect . GE sending out a tech sometime next week. I will reply his answer when I get it. Thanks for the advise


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## Zog

Voltech said:


> As for reading the book, No I didnt. But Im sure that I have removed all the shipping bolts and braces. We installed 3 like units that were all braced the same. Its just odd that this one unit is so loud. I will put card board on the walls and floor in the morning. My dad was a studio musician, I kinda understand an acoustical effect . GE sending out a tech sometime next week. I will reply his answer when I get it. Thanks for the advise


Loosen the hardware on the isolation pad?


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## Electric_Light

Zog said:


> Higher than rated voltage being applied to transformer windings. Must be measured with a true RMS meter.​


If an average response meter and a true-RMS meter reads the voltage differently enough to matter, you have too much harmonics that must be dealt with.


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## Voltech

GE came out today with a DB meter. It was just below spec. At least its off me. Change order coming :thumbsup: to RR with one that has a lower DB. Which is about 2 times as much money.

To me, it still seems loud


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## Zog

Voltech said:


> GE came out today with a DB meter. It was just below spec. At least its off me. Change order coming :thumbsup: to RR with one that has a lower DB. Which is about 2 times as much money.
> 
> To me, it still seems loud


What was the reading? Or did we just let GE say it was fine and if you want a quiter one they will sell you one? I have the specs of acceptable DB for different size transformers, I will double check it for you.


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## Voltech

Zog said:


> What was the reading? Or did we just let GE say it was fine and if you want a quiter one they will sell you one? I have the specs of acceptable DB for different size transformers, I will double check it for you.



The reading was 45 db, I was told that 50 was the max.

Here is that Catalog # GE 9T83B3874G13 its a 3 phase 75 kva


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