weressl
Esteemed Member
i posted a thread here a few days ago, about a VERY noisy
300 kva xfmr, actually several of them...... nema 1's,
in electrical rooms.
now, this sunday, i'm downing them for PM, megger,
torquing, vibration pad inspection, etc.
assuming there is nothing mechanically or electrically
wrong with these xfmr's, and the noise is just lamination's
fluttering, and that is not something that is solvable without
replacing the xfmr's.... here is my idea....
there is a product called mass loaded vinyl, that is a nonconductive
rubber sheet weighing about 1 lb per sq. ft. it comes with a 1/4"
foam backing, and you attach it to a surface by the foam, so the
vinyl is floating 1/4" above the surface, and not mechanically coupled
to it except by the foam.....
cover the exterior of the transformer case with this, leaving all air
vents, slots, and whatnot uncovered, so that the sheet metal case
and front and back covers are covered with this product, to dampen
sound.....
this stuff has a greater sound isolation than lead sheets of the same
thickness, and is nonconductive, and i'm wondering if, as it is outside
of the enclosure, it would compromise the UL listing of the xfmr?
you still will have airborne sound coming out the vents, but i'm guessing
a huge amount of it would be dampened....
whatchoo guys think?
the stuff is NOT cheap, but it sure does work.... i used it in a sound
studio, and it rocks. nothing much goes thru it.
Couple of thoughts:
- you are modifying the equipment and potentiall violating it's listing, so NEC may frown on that.
- the transformers are tested and the conductive case also acts as a heat-shink, so it contributes to the heat removal even though the majority of the heat removal by air-convection via the vent holes largely remains as designed.
- the insulating material that you intend to use as a sound buffer has temperature limitation and as it ages and deteriorates it COULD fall on the core and winding, causing it to overheat and could be a fire hazard.