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Re: [RoboMower] Ames??? - melting gears?

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  • Rick Gard
    The Roomba has a visual tachometer to compare current through motors versus actual motion; it initiates escape routines when this error state is triggered.
    Message 1 of 31 , Sep 3, 2007
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      The Roomba has a visual tachometer to compare current
      through motors versus actual motion; it initiates
      escape routines when this error state is triggered.
      Couldn't Robomower do that too?

      Richard


      --- IGGYandSvetlana <iggyandsvetlana@...>
      wrote:

      > Ames, STC and FR of Israel, are you people
      > listening?
      >
      >
      >
      > Ames, this would be a good time for you to chime in.
      >
      >
      >
      > IGGY
      >
      >
      >
      > _____
      >
      > From: RoboMower@yahoogroups.com
      > [mailto:RoboMower@yahoogroups.com] On Behalf
      > Of tbaka3
      > Sent: Sunday, September 02, 2007 9:59 PM
      > To: RoboMower@yahoogroups.com
      > Subject: [RoboMower] Re: Spare parts needed for my
      > RL 1000
      >
      >
      >
      > --- In RoboMower@yahoogrou
      > <mailto:RoboMower%40yahoogroups.com> ps.com,
      > "doodieb2001" <doodieb@...> wrote:
      > >
      > > Well, if I look it up in the service manual, which
      > I found on the
      > > net, the it shows on page 11, that there are only
      > 2 thermistors;
      > one
      > > for the right drive motor and 1 for the right
      > mowing motor, period.
      > I
      > > don't think it is a manufacturing mistake it is a
      > design mistake.
      > BTW
      > > the plug on the mainboard only allows 2
      > thermistors also. So when I
      > > have the mower fixed, I will add 3 Bimetal
      > thermoswitches, for 4$ a
      > > piece and this problem is gone.
      > >
      > > --- In RoboMower@yahoogrou
      > <mailto:RoboMower%40yahoogroups.com> ps.com,
      > "wild_bill_howell"
      > > <ALLAMERICANARC@> wrote:
      > > >
      > > > <Friendly saved on Thermistors; the right
      > > > > hand motor was protected whereas the left hand
      > motor got too
      > hot
      > > and
      > > > > damaged the gearcase.>
      > > > -------------------------
      > > > That, sir, if accurate, is a defect in
      > manufacturing and should be
      > > > covered by warranty, no matter how old your unit
      > is....
      > > > you didn't pay for partial thermal protection.
      > > >
      > > > Raise holy hell until you get it fixed at no
      > cost to you.
      > > > If your retailer or STC or Friendly Robotics
      > don't provide
      > > > satisfaction, complain to your State, the Feds,
      > including the
      > import
      > > > agencies.
      > > > Alert the media.
      > > >
      > > > I wonder how many other defective 1000s are out
      > there?
      > > >
      > > > I'd push for a recall on every one of them if
      > just one more was
      > > > reported...
      > > > Such egregious lack of quality control is
      > outrageous!
      > > > Sic'em!!!!!
      > > >
      > > > Also, this is another problem which could be
      > avoided if the mower
      > > > didn't get stuck-on-stupid. <shaking head>
      > <shaking fist>
      > > >
      > > >
      > > > WB
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > --- In RoboMower@yahoogrou
      > <mailto:RoboMower%40yahoogroups.com> ps.com,
      > "doodieb2001" <doodieb@> wrote:
      > > > >
      > > > > My Robomower RL 1000 died, because it got
      > stuck on a root. The
      > > drive on
      > > > > the left hand side is broken. Who knows where
      > I can get an
      > empty
      > > gear
      > > > > frame, a pinion which mounts to the drive
      > motor and a large
      > > sprocket
      > > > > (with the ball bearing). BTW: Friendly saved
      > on Thermistors;
      > the
      > > right
      > > > > hand motor was protected whereas the left hand
      > motor got too
      > hot
      > > and
      > > > > damaged the gearcase.
      > > > >
      > > > > Thank you very much!
      > > > >
      > > >
      > >
      >
      > My Robomower trail is littered with gear cases.
      > 1st gear case repaired under warranty. Pinion gear
      > melted. (Paid
      > shipping both ways.) Mower got stuck in soft soil
      > near palm tree.
      > 2nd gear case replaced out-of-warranty with new
      > "improved material"
      > pinion gear which...melted. Stuck on a tree root.
      > 3rd gear case... Yup! pinion gear.
      > 4th gear case just replaced.
      >
      > Will Robomower add a thermistor to the other
      > unprotected drive motor?
      > Add thermistors to the two unprotected cutter
      > motors?
      > Modify the program to sense drive wheels turning but
      > compass readings
      > not changing?
      > Change pinion gear material to carbon graphite or a
      > more durable
      > material?
      > Modify drive motor attachment to gear case to
      > dissipate plastic
      > melting motor heat?
      >
      > Nope...there is no design problem with the current
      > gear case!
      >
      >
      >
      >
      >
      > [Non-text portions of this message have been
      > removed]
      >
      >



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    • wild_bill_howell
      ... They will be if air is forced through them as I suggested. WB ... rotor, ... really the ... could ... even ... melting out
      Message 31 of 31 , Sep 6, 2007
      • 0 Attachment
        > They have some small slots on the ends but they're not cooling slots.>
        -------------------------------
        They will be if air is forced through them as I suggested.

        WB

        --- In RoboMower@yahoogroups.com, Danny Miller <dannym@...> wrote:
        >
        > They have some small slots on the ends but they're not cooling slots.
        > The big cooling slots are on the sides of the motor.
        >
        > Danny
        >
        > wild_bill_howell wrote:
        >
        > >>Still I am unsure if the shroud temp is even a good indicator of the
        > >>problem.>
        > >>
        > >>
        > >-------------------------
        > >May not be.
        > >
        > >Perhaps a 24VDC blower attached to a shroud to surround the ends of
        > >both drive motors, a simple rubber material held by hose clamps, with
        > >a duct/hose connected to a squirrel cage blower might do the trick.
        > >The drive morors have cooling slots on both ends, so just blow air
        > >down the center of the motor to cool the rotor.
        > >That oughtta work.
        > >
        > >WB
        > >
        > >
        > >--- In RoboMower@yahoogroups.com, dannym@ wrote:
        > >
        > >
        > >>That might do it.
        > >>
        > >>Still I am unsure if the shroud temp is even a good indicator of the
        > >>problem.
        > >>
        > >>Cooling would also not help much, because the outer housing temp is
        > >>generally not the issue at all. The wiring is all on the motor's
        rotor,
        > >>the rotor heat conducts down the shaft and end bearings. So
        really the
        > >>rotor's getting about all the cooling that is possible. The shaft
        could
        > >>be cooled, the steel shaft isn't even a good heat conductor so really
        > >>not a whole lot of cooling would be needed to keep the pinion's temp
        > >>
        > >>
        > >down.
        > >
        > >
        > >>Really, all-brass pinions wouldn't be a bad idea. Would be very
        > >>difficult to mount aftermarket though and I don't know where you'd
        even
        > >>get them made. Nor would it resolve the issue of the motor
        melting out
        > >>of the gear frame.
        > >>
        > >>I honestly think it all comes down to the Robomower needing a wheel
        > >>tach, one NOT on the powered wheel that's spinning.
        > >>
        > >>Danny
        > >>
        > >>----- Original Message -----
        > >>From: wild_bill_howell <ALLAMERICANARC@>
        > >>Date: Sunday, September 2, 2007 11:18 pm
        > >>Subject: [RoboMower] Re: Spare parts needed for my RL 1000
        > >>To: RoboMower@yahoogroups.com
        > >>
        > >>
        > >>
        > >>>>Where are you going to find a bimetal thermoswitch with the required
        > >>>>
        > >>>>
        > >>>DC rating?>
        > >>>------------------
        > >>>A work-around is to use a NC thermoswitch, wired in series with the
        > >>>the bumper wire connected to the "grid" part of the bumper.
        > >>>When the switch opens that circuit, the mower will stop and
        > >>>indicate a
        > >>>bumper fault.
        > >>>It should be easy to determine if such a fault is really a
        > >>>loose/broken bumper wire, or whether the thermoswitch has interrupred
        > >>>the circuit.
        > >>>
        > >>>Perhaps someone will develop an aluminum heat sink for the motors, or
        > >>>perhaps just wire some DC fans to force-cool the motors..
        > >>>such low current draw for fans should have a minimum lessening of
        > >>>mower run-time.
        > >>>
        > >>>WB
        > >>> --- In RoboMower@yahoogroups.com, dannym@ wrote:
        > >>>
        > >>>
        > >>>>Where are you going to find a bimetal thermoswitch with the
        > >>>>
        > >>>>
        > >>>required DC
        > >>>
        > >>>
        > >>>>rating? That's a good number of amps on a hill and DC ratings are
        > >>>>significantly lower than AC.
        > >>>>
        > >>>>I suspect the difference between normal temps and overheating may be
        > >>>>touchy. There is a also a problem in that higher temps at the
        > >>>>
        > >>>>
        > >>>shroud,> where the thermistor can measure them, may not accurately
        > >>>correspond> with elevated rotor temps inside the motor. I had the
        > >>>right side melt
        > >>>
        > >>>
        > >>>>down on an RL500 with the "early" revision of the gear frame even
        > >>>>thought there was a thermistor on that side.
        > >>>>
        > >>>>I must point out that regrettably the pinion (little gear mounted
        > >>>>
        > >>>>
        > >>>on the
        > >>>
        > >>>
        > >>>>motor shaft itself) is NOT replaceable, it's permanently mounted
        > >>>>
        > >>>>
        > >>>on the
        > >>>
        > >>>
        > >>>>motor shaft. You will need a whole new motor.
        > >>>>
        > >>>>Danny
        > >>>>
        > >>>>----- Original Message -----
        > >>>>From: doodieb2001 <doodieb@>
        > >>>>Date: Sunday, September 2, 2007 8:19 pm
        > >>>>Subject: [RoboMower] Re: Spare parts needed for my RL 1000
        > >>>>To: RoboMower@yahoogroups.com
        > >>>>
        > >>>>
        > >>>>
        > >>>>>Well, if I look it up in the service manual, which I found on
        > >>>>>
        > >>>>>
        > >>>the
        > >>>
        > >>>
        > >>>>>net, the it shows on page 11, that there are only 2
        > >>>>>
        > >>>>>
        > >>>thermistors;
        > >>>
        > >>>
        > >>>>>one
        > >>>>>for the right drive motor and 1 for the right mowing motor,
        > >>>>>
        > >>>>>
        > >>>period.
        > >>>
        > >>>
        > >>>>>I
        > >>>>>don't think it is a manufacturing mistake it is a design
        > >>>>>
        > >>>>>
        > >>>mistake.
        > >>>
        > >>>
        > >>>>>BTW
        > >>>>>the plug on the mainboard only allows 2 thermistors also. So
        > >>>>>
        > >>>>>
        > >>>when I
        > >>>
        > >>>
        > >>>>>have the mower fixed, I will add 3 Bimetal thermoswitches, for
        > >>>>>
        > >>>>>
        > >>>4$ a
        > >>>
        > >>>
        > >>>>>piece and this problem is gone.
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>
        > >>>
        > >>>
        > >>>Yahoo! Groups Links
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >
        > >
        > >
        > >
        > >
        > >Yahoo! Groups Links
        > >
        > >
        > >
        > >
        > >
        > >
        >
        >
        > [Non-text portions of this message have been removed]
        >
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