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Brushless DC Motors suitable for Underwater?

  1. Nov 19, 2008 #1
    Hi people,

    im new to this forum. I'm currently working on a underwater ROV for my school project. We did a experiment recently on the performance of our ROV. We met up with some problems on the motor & the propeller for the thrusting. The motor stalls just after 5secs. So im thinking is there any wrong with our motor? Cuz im afraid that our brushless DC motor might not be suitable for underwater usage. The motor we bought is "Oriental motor Brushless DC motor" model BLM5100k-A. Is there anyone had tried making a ROV using those motors? Pls advise. Any help will be very much appreciated!

    Thank you
  2. jcsd
  3. Nov 20, 2008 #2


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    Staff: Mentor

    The motor is sealed in a water-tight enclosure, right? The motor doesn't know it's underwater, or at least it shouldn't. What do you mean by "stalls"?
  4. Nov 21, 2008 #3
    Yup it in seal in a high density plastic material called delrin with O rings & rubber seals at the opening. It is already a water proof seal so im sure there wun be any water that could leaks into the motor. I did a experiment on the motor & driver mounted wif a marine propeller in the water. Everytime i on the power supply, the propellers starts to spin smoothly for the first 5secs. After that it will stop automatically. Im suspecting is it whether the motor couldnt run at consistent pressure in the water. Cuz when i tested the motor & propeller on air, it works perfectly fine. Or is it becuz there is not enough current or is there other extra components to make this work. Eg, like a potential meter. Pls advise......
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