NOISY INVERTER !

[Hugh Conway]

 Hope some of you can advise on this one. I have recently replaced my inverter with a new one of the same make and model. Magnum MS4024PAE.
This new unit seems to produce far more noise than the one it replaced. The noise in question is not RF noise, but a very audible hum. Sounds like 60Hz transformer hum, and occurs at all times when the inverter is operating. I realize that transformer hum is normal, but this seems excessive. Magnum has not been all that helpful in resolving the issue.
Is there anyone who knows what an acceptable Db level for this unit would be? Is there a "bench test" Db range for this unit?
Magnum will have a look at it if I send it back under warantee, but If they say nothing is amiss, I will have to pay freight both ways, which is quite expensive as I am in a remote area........and additional pay for the testing. If Magnum says this is normal, I will still have to listen to this crazy making buzz which can be heard nearly everywhere in the house.
Cheers,
Hugh

[Thob]

It would seem to me that if you replaced the inverter with the same make/model and it makes lots of noise, then there is something wrong with the new inverter.  Often noise in a transformer device is something loose - the transformer mounting, the case rubbing against the transformer, etc.  If it doesn't void the warranty, I'd open up the case (power off first) and take a look - you might compare to the old one and see if anything is missing or loose.  Look for rubber mounting feet, loose bolts, missing "goop" (if it's a toroid transformer).

If you do take the case off, be sure you're safe first.

[BruceM]

A poorly made transformer itself can cause this type of noise.  Welcome to the new world of no customer service, or idiotic service.

[Hugh Conway]

I had the loan of a Db meter and read 60db got this inverter. 60Db buzz is sure a pain in the ear! A meter purchased on ebay is on its way, so I will be able to compare the sound levels of this new inverter with the older quieter one. Magnum will not say what they consider to be an acceptable range for Db level, so I really have no comparison with what would be a warantee level problem.
Anyone have a similar inverter and can say what their Db level is?
Any info/assistance is appreciated.
Cheers,
Hugh

[Carlb]

Hugh,

If you have a smart phone you can download any number of decent db meter apps for free.

[Hugh Conway]

@ Carib......We are out here on the edge, no cell service at this location, so we don't have/need smart phone. The borrowed Db meter was actually a visitor with smart phone and Db app.
thanks for the tip though
Cheers,
Hugh

[mobile_bob]

others have mentioned things like loose transformer mounts and the like... and i concur

if you can take the cover off,  and not void your warranty, you might just do that and carefully with a wooden dowel
prob around the transformer to see if you can determine if it is mounted tightly and securely, also check things like the plate it mounts too and anything else that might cause the issue... just gently push around with the dowel to see if the noise shifts in level to get an idea where the problem might be.

it also might be a loose laminate in the transformer core. so push around on the laminates where you can.

it also might be a loose bobbin, the core the wire is wound on. push around on that to to see if you can hear a difference.  sometimes you can have a loose bobbin that will raise all sort of heck,  if that is the case you may have to cut some wooden wedges to shove in between the bobbin core and the laminate stack to secure things.  they also make some sort of epoxy to secure things too.

if it were me i would be checking things out, and see if i could locate the offending culprit, then make the necessary repairs or alterations to quiet the thing down.  the thing is if something is loose, it will only get worse over time, and in some cases lead to early failure of a component such as the transformer itself.

one last thought, you might find a larger piece of flat sheet metal that is amplifying the problem, or telegraphing the noise and making it louder.... if that is the case  i would be tempted to stick on a big hunk of modeling clay as a temporary fix to see if i could deaden the offending panel... then if that helped maybe look into some other more permanent stuff to replace the clay with like maybe a wad of rtv silicone.

when one replaces a unit with an identical unit and finds the new one to be significantly noisier than the first one, that to me is a red flag that something is amiss and needs attention.

bob g

[Hugh Conway]

@Mobile Bob
Thanks for your suggestions Bob. On your suggestion, I did poke around in there. Found that if I loosened the 4 transformer mounting screws, the noise is much reduced. I think it may not be possible to eliminate it entirely, but there has been a reduction to a tolerable level. Still produces a louder hum than the original, but at least it is improved to the point that it is no longer heard all over the house!
Thanks.
Cheers,
Hugh

[BruceM]

That does point strongly to a poorly made transformer. Glad you were able to get some relief with isolating it a bit.

[Hugh Conway]

@BruceM....
Thanks for that info, I know you are well versed in electronic stuff. Now if I could just get Magnum to acknowledge that as well!

Cheers,
Hugh

[mike90045]

Maybe using a piece of linoleum tile or some cork gasket material as a vibration isolator would be helpful.  leaving mounting bolts loose, invites them to eventually fall off.