Thanks for the reply regarding noise from the gear box. I'm planning on going down the same road, using a gear box in lieu of a belt driven reduction gear.
Bob
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On Wed, 9/21/16, king_of_neworleans <no_reply@yahoogroups.com> wrote:
Subject: [Electric Boats] Re: Decibels
To: electricboats@yahoogroups.com
Date: Wednesday, September 21, 2016, 8:25 AM
I forgot to mention, my
noise is negligible at very low speeds but also at very high
speeds. Above 70 amps, it quiets down a lot. I am thinking
this has to do with the shortened dwell time per pole in
relation to the pulse width, and that the midrange noise
would quiet down with a sine wave input. I am going to try
to borrow a sinewave controller from someone when I get back
from my next job, and rig some way for measuring noise
level, and compare the two. I might also try a gearbox with
a higher reduction ratio, to get motor RPM up into that
silent zone. Could be the load on the motor contributes to
the noise. I know my shaft is not as true as I would like it
to be, though it is pretty close. It is a bronze shaft and I
am considering going stainless on my next haulout. So far, I
have resisted installing any U-joints in my shafting,
because my motor mount is very finely adjustable, and I just
don't trust them enough to put them in without a
demonstrable need.
In my
limited experience and possibly flawed perception, BLDC
motor noise has a strong "click" component, as the
rotor gets micro-flexed to coin a phrase, with each pole
passage. Since accelleration is not an issue, it seems that
more rotor mass and rigidity might make for a quieter motor
without significant performance degradation.
Has anyone done any noise
comparisons between axial flux and radial flux motors?
Well I have to fly to Cyprus
and catch a ship tomorrow so I may not be on this board as
much as I would like, for the next few months. If I
don't chime in it's because I am at sea with no or
little internet access.
Posted by: bob jennings <sabre281@yahoo.com>
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