Running Brushless DC in Water
Posted: Nov 11th, 2012, 11:44 am
Hello All,
Over the weekend I wanted to do some proof of concept tests to prove to myself that running a brushless motor submerged in water would not have any adverse affects on the motor itself.
I am happy to say the tests were successful. (If you don't count the small tsunami that occurred on the first test BEFORE I learned that putting a cover on the "water tank" is vital for indoor testing!)
For this test, the key components I used were the following:
-Arduino Uno
-PS2 Controller
-Turnigy Brushless ESC 18A w/ Reverse
(http://www.hobbyking.com/hobbyking/stor ... oduct=7189)
-Turnigy D2836/11 750KV Brushless Outrunner Motor
(http://www.hobbyking.com/hobbyking/stor ... duct=12922)
I have included some links the videos of each test here:
Dry Test: http://youtu.be/seqx2J-JsHM
Fresh Water: http://youtu.be/J7mG_En5uRs
Salt Water: http://youtu.be/qOzl1l4YX6E
Some key points from this test:
1.) There is a significant difference in the current draw in a dry vs wet test.
2.) There is a difference in the current draw in fresh vs salt water.
3.) The motor i used in this testing has a fan shaped housing that creates a difference in air flow (and water flow) depending on the rotational direction. This caused a difference in the current draw depending on the rotational direction.
4.) For the test, I filled my tupperware container completely full, then put the cover on. This reduced/ eliminated any cavitation caused by the vortex in the water drawing air into the water flow around the motor. On initial testing, this cavitation caused erratic current readings. In my opinion, using a sealed container better simulates a submerged thruster.
5.) After the salt water test, I thoroughly rinsed out the motor with fresh water and placed near a radiator to speed up the dring process. I have not applied any lubricant or other oils to this motor. At this time, I do not plan on applying any lubricants to the motor. My goal is to evaluate how the motor will cope with this.
If you have any follow up questions, please feel free to ask!
Ryan "KR2_Diving"
Over the weekend I wanted to do some proof of concept tests to prove to myself that running a brushless motor submerged in water would not have any adverse affects on the motor itself.
I am happy to say the tests were successful. (If you don't count the small tsunami that occurred on the first test BEFORE I learned that putting a cover on the "water tank" is vital for indoor testing!)
For this test, the key components I used were the following:
- Thruster Test layout
- Thruster Test layout.jpg (443.41 KiB) Viewed 5220 times
-PS2 Controller
-Turnigy Brushless ESC 18A w/ Reverse
(http://www.hobbyking.com/hobbyking/stor ... oduct=7189)
-Turnigy D2836/11 750KV Brushless Outrunner Motor
(http://www.hobbyking.com/hobbyking/stor ... duct=12922)
I have included some links the videos of each test here:
Dry Test: http://youtu.be/seqx2J-JsHM
Fresh Water: http://youtu.be/J7mG_En5uRs
Salt Water: http://youtu.be/qOzl1l4YX6E
- Test Results
- thruster test result.jpg (30.05 KiB) Viewed 5220 times
1.) There is a significant difference in the current draw in a dry vs wet test.
2.) There is a difference in the current draw in fresh vs salt water.
3.) The motor i used in this testing has a fan shaped housing that creates a difference in air flow (and water flow) depending on the rotational direction. This caused a difference in the current draw depending on the rotational direction.
4.) For the test, I filled my tupperware container completely full, then put the cover on. This reduced/ eliminated any cavitation caused by the vortex in the water drawing air into the water flow around the motor. On initial testing, this cavitation caused erratic current readings. In my opinion, using a sealed container better simulates a submerged thruster.
5.) After the salt water test, I thoroughly rinsed out the motor with fresh water and placed near a radiator to speed up the dring process. I have not applied any lubricant or other oils to this motor. At this time, I do not plan on applying any lubricants to the motor. My goal is to evaluate how the motor will cope with this.
If you have any follow up questions, please feel free to ask!
Ryan "KR2_Diving"