"bud--" wrote in message
...
Robert Green wrote:

Today I'll go "sound mapping" again so I can report back
which frequencies are the worst offenders.


The frequencies may change as you load the motor - go from sucking air
to pulling a vacuum.

Interesting observation. The whining noise does change considerably when
something large enough to block the nozzle gets stuck without getting sucked
in. In that case, it's a good thing to be able to hear the increase in
noise and remove the blockage before the motor goes into thermal overload.
Lots of things to consider when boxing this bugger up!

--
Bobby G.