[Dprglist] Motor Noise Level

[Karim Virani]

We've switched entirely to the REV ultraplanetary system
<https://www.revrobotics.com/rev-41-1600/>. You didn't really describe the
power/torque envelopes you are looking for but our robots are typically 30
to 40 lbs and are fairly zippy even on just two motors. Some teams use up
to 4 of these, usually because they have a mecanum drive train, but some
might double up motors for maximum acceleration. Here's a video of our
differential drive robot on 2 of them <https://youtu.be/BsG_3AO7zN0?t=21>.
Much of the noise in that video actually comes from the turret.

The $36 motors are pretty quiet and very versatile. The output can be
geared from 1:1 all the way to 143:1 (with the purchase of alternate gear
stages). You can stack from 0 to 3 gearbox cartridges (stages) to come up
with a 28 different final gear ratios.

Of the 15 or so of these we have, one has had a bad gearbox. I don't know
if it was a bad cartridge or one of my students over torquing the gearbox
assembly. They are pretty resistant to burn out under stall conditions.

The output shaft is 5mm hex which is compatible with 6mm round bearings.
Even better, you can mount your driven component without a shaft to the
face of the gearbox with M3 bolts where it is supported by a good ball
bearing. I still never recommend direct drive for any wheel on a heavy
robot, but these can sustain pretty solid axial and transverse loading
created by your drive train. They also have a 1/2" hex shaft adapter.

These are 12 volts. The encoder is shaft mounted, 28 counts per revolution,
6,000 rpm no load. Max power is 15W, stall torque is .105Nm, stall current
8.5A.

If you want to pay extra for really long life, quieter operation and higher
performance at speed, they have a brushless motor option, but that changes
your drive electronics substantially. It also doesn't support higher loads,
but I'm not sure why. We've used their larger brushless motors but have not
used the smaller one compatible with this gear system.

product page: https://www.revrobotics.com/rev-41-1600/
video: https://www.youtube.com/watch?v=tmB8c-cCHd8
manual: https://docs.revrobotics.com/ultraplanetary/

-karim

On Fri, Jan 22, 2021 at 9:49 AM Pat Caron via DPRGlist <
dprglist at lists.dprg.org> wrote:

> Hi all, at the last RBNV, there were several comments on how much noise
> the "Wood Monster" made.  My wife agrees that it is quite noisy.
> Can anyone recommend a quieter gear motor c/w encoder capable of moving
> the 30lbs robot?  Presently the motors are powered by a 12V SLA battery and
> speed at full load is 120 RPM with a ~6 inch wheel.
>
> Thanks,
> ...Pat
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