The "tube" machine that I was in at our local hospital made a lot of
noise. It did make banging noises, as if large internal components were
moving and stopping rapidly. It wasn't a highly repetitive noise but
happened every minute or so, in between all the various hums and so
forth. I'm not sure why sudden reversal of polarity would cause
displacement of air, unless the mechanical parts were moving along with it.
> As I understand it, the noise comes from the reversing of the polarity of the
> magnet. It is not really any physical movement, just a sudden reversal of the
> polarity causes a rapid displacement of the air inside, causing a shock wave,
> also known as sound. I may be off in that analysis, but it is pretty close.
|