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Bad tidings! I'm experiencing a rather high failure rate with the new type 9V
geared motor (#43362). This motor has been discussed before
(http://news.lugnet.com/robotics/?n=19204&t=i&v=a)
This motor can be easily recognised: when you twirl the shaft it turns very
little and quickly comes to a halt. And it is lousy for doing the Magic Motor
Test - connect an electric wire from one motor to the other. Twirl the shaft of
one motor, the other motor should turn at almost the same speed.
Out of 20 of these motors from 10 brand new RIS 2.0 sets, 6 motors have failed
on me within less than a year. Some failed within just a couple of weeks. The
common pattern of failure was that the motors will begin to turn slowly with a
grinding sound, stiffened up and eventually will get jammed.
A possible cause for this behaviour was given at
http://news.lugnet.com/robotics/?n=19212
I'm beginning to suspect that there is a design and/or manufacturing fault in
these new type motors that should be drawn to TLC's attention. Or are they
already aware of this? If so, why are they still putting them out?
Would appreciate to know what is the experience of others just to be sure I'm
not jinxed!
C S Soh
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In lugnet.robotics, Chio Siong Soh wrote:
> Bad tidings! I'm experiencing a rather high failure rate with the new type 9V
> geared motor (#43362). This motor has been discussed before
> (http://news.lugnet.com/robotics/?n=19204&t=i&v=a)
>
> This motor can be easily recognised: when you twirl the shaft it turns very
> little and quickly comes to a halt. And it is lousy for doing the Magic Motor
> Test - connect an electric wire from one motor to the other. Twirl the shaft of
> one motor, the other motor should turn at almost the same speed.
>
> Out of 20 of these motors from 10 brand new RIS 2.0 sets, 6 motors have failed
> on me within less than a year. Some failed within just a couple of weeks. The
> common pattern of failure was that the motors will begin to turn slowly with a
> grinding sound, stiffened up and eventually will get jammed.
>
> A possible cause for this behaviour was given at
> http://news.lugnet.com/robotics/?n=19212
>
> I'm beginning to suspect that there is a design and/or manufacturing fault in
> these new type motors that should be drawn to TLC's attention. Or are they
> already aware of this? If so, why are they still putting them out?
>
> Would appreciate to know what is the experience of others just to be sure I'm
> not jinxed!
>
> C S Soh
I had the same problem with one of mine. Using them in a fast RC car might do
this if it gets slammed into something. I will inform Nathanael Kuipers of the
problem since he works at TLC and can tell the proper person.
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In lugnet.robotics, Nathan Bell wrote:
> In lugnet.robotics, Chio Siong Soh wrote:
> > Bad tidings! I'm experiencing a rather high failure rate with the new type 9V
> > geared motor (#43362). This motor has been discussed before
> > (http://news.lugnet.com/robotics/?n=19204&t=i&v=a)
>
> I had the same problem with one of mine. Using them in a fast RC car might do
> this if it gets slammed into something. I will inform Nathanael Kuipers of the
> problem since he works at TLC and can tell the proper person.
Thanks!
No, these motors were only used for FLL type challenges, not in fast RC cars.
I can submit the bad motors for *CSI* and 'autopsy' if need be.
C S Soh
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In lugnet.robotics, Chio Siong Soh wrote:
> In lugnet.robotics, Nathan Bell wrote:
> > In lugnet.robotics, Chio Siong Soh wrote:
> > > Bad tidings! I'm experiencing a rather high failure rate with the new type 9V
> > > geared motor (#43362). This motor has been discussed before
> > > (http://news.lugnet.com/robotics/?n=19204&t=i&v=a)
> >
> > I had the same problem with one of mine. Using them in a fast RC car might do
> > this if it gets slammed into something. I will inform Nathanael Kuipers of the
> > problem since he works at TLC and can tell the proper person.
>
> Thanks!
> No, these motors were only used for FLL type challenges, not in fast RC cars.
>
> I can submit the bad motors for *CSI* and 'autopsy' if need be.
>
> C S Soh
I sent Nathanael Kuipers an email regarding the motors and asked him to forward
it to the proper person.
Do you think it is excessive torque, excessive use, or just a bad piece design
that causes this problem?
Nathan
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In lugnet.robotics, Nathan Bell wrote:
> Do you think it is excessive torque, excessive use, or just a bad piece design
> that causes this problem?
I suspect it's bad design. Perhaps the way the brushes rub on the PCB as pointed
out by Philo (http://www.philohome.com/motors/motor.htm). "This higher friction
explains why 43362 stops faster when you give the shaft a twirl, and why its
no-load current is higher (9mA vs. 3.5mA)".
Its performance is degraded compared to the earlier motor (#71427). The only
advantage seems to be its lighter weight.
In previous posts misgivings have been expresed about this new motor which I am
now re-voicing:
http://news.lugnet.com/robotics/?n=19204
http://news.lugnet.com/technic/?n=8601
C S Soh
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In lugnet.robotics, Chio Siong Soh wrote:
>
> Its performance is degraded compared to the earlier motor (#71427). The only
> advantage seems to be its lighter weight.
I'm guessing it may also be cheaper / easier to manufacture.
ROSCO
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In lugnet.robotics, Ross Crawford wrote:
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In lugnet.robotics, Chio Siong Soh wrote:
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Its performance is degraded compared to the earlier motor (#71427). The only
advantage seems to be its lighter weight.
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Im guessing it may also be cheaper / easier to manufacture.
ROSCO
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I burned out two of these motors in a high-torque situation (my Great Ball
Contraption module prototype) which I posted about
here and
here.
I dont like them for their friction, their louder sound, and that they feel
cheaper than the originals (weight, mostly).
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In lugnet.robotics, Jordan Bradford wrote:
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I burned out two of these motors in a high-torque situation (my Great Ball
Contraption module prototype) which I posted about
here and
here.
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What a relief to know Im not jinxed after all.
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I dont like them for their friction, their louder sound, and that they
feel cheaper than the originals (weight, mostly).
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And their high mortality rate.
I hope the proper person at TLC is looking into it.
C S Soh
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