Question to the BR team:
We are experiencing a bit of sand in one of our thrusters. See photos. Should this amount of sand be able to enter the thruster? We also found some in the electronics enclosure. Did not fully pass the o-rings, but was not a good feeling seeing this.
Also a question about the bigger holes in the rotor, what is their purpose? Cooling? Friction?
Am I just being paranoid, or is this something to worry about?
Hi @Erlingns95 !
That much sand is definitely something to be concerned about!
Sand is the mortal enemy of the innovative flooded Blue Robotics brushless motors - especially sand or sediment with small ferrous (magnetic) particles! When you drive your vehicle into the ground, especially if it is hard enough to push sand partially into the enclosure, you are in effect sandblasting the coatings used on the rotor and stator. Once these coatings wear away, materials can be exposed that will corrode! Even after a good fresh water rinse, rust can form and eventually cause the motor to lock-up and not operate. This is unfortunately a fundamental limitation to this motor design in some ways - the T500 has an additional shield on the rotor and so can be a bit more robust.
If you encounter sediment in a big way, it is good practice to disassemble and flush each thruster. If magnetic particles are found, they often have to be wiped away (a towel and o-ring pick are a good tool for this.) If you find areas where the coating has clearly been damaged, you may want to attempt recoating them - we’ve not tested this but perhaps clear nail polish or other epoxy coatings would be well suited - however this may only slightly extend the components lifespan after this initial wound.
The larger holes in the rotor are indeed for cooling, to allow more water to pass by the stator (where most of the heat is coming from.)
Can you say something about the dynamics of the water-flow through the thruster? Will the direction of the cooling-water change depending on the thrusters´ rotation? This might not be your biggest focus-point but a member of our team was quite curious.
Does it by any chance exist some drawings of the estimated cooling-flow?
Wow that is a lot of sand Erling - thanks for uploading. Apologies in advance if a silly question but wondering if the correct locking cord was installed on the electronics enclosure cap? I wouldnt think there is enough space for that much material to accumulate unless the shorter locking cord for the 3 inch enclosure was used?
Thanks for the maintenance/repair tips Tony - interesting to see the updates for these motors (inner metal sleeve and overlapping impeller collar). Just wondering if the current M200s also have these design features?
Hi @BillyBudd -
Those features are not present in the M200 or T200, but are planned to be incorporated eventually!
Hi @XYZEng -
I believe the upcoming updates are adding an alternative, single fastener mounting solution to the thruster nozzles - no change to the stator or rotor (yet…)
The previous mounting method will be preserved, not to worry!
