Science Buddies: "Ask an Expert"

Motor specifications:

Shell length: 50mm

Total length: approx. 76mm

Diameter: 31mm

Operating voltage: 3–10V

Current at 6V: 0.8A

Current at 9V: 1A

No-load speed at 7.4V: 16,800 RPM

Propeller diameter: approx. 39mm

Waterproof, designed for micro ROV/model boats

Could you please let me know:

1. Whether this motor is suitable for your ROV design.

2. What additional components (motor driver, frame materials, power supply, etc.) I would need to use this motor in your build.

3. If any changes to your design would be required to support this motor.

Hello.

Thanks for sharing the motor specs, this looks like a solid option for a micro ROV. With a 7.4V no-load speed of 16,800 RPM and a current draw of 0.8–1A, it should provide decent thrust, assuming your ROV isn’t too heavy. To use it, you’d need a motor driver that supports up to 10V and 1A continuous current, a waterproof frame or housing, and a compatible 2S LiPo battery. Depending on your existing design, you might need to adjust the motor mount or propeller clearance slightly, but overall, it seems like a good fit.

Just a follow-up to the expert's suggestions ... here's a link that shows several fascinating Science Buddies science/engineering projects involving ROVs.

Be sure to let us know if you are considering any of these projects or if you have more questions.

Good luck!

https://www.sciencebuddies.org/science- ... ects?s=ROV

This question is specifically about this project: https://www.sciencebuddies.org/science- ... rwater-ROV

Hi,

What you need to do in this case is look up the current/voltage capabilities of the motor driver, which for this project is the L293D H-bridge. You can find that info by googling "L293D datasheet":

https://www.digikey.in/en/htmldatasheet ... 0/1/l293dd

where we see that the L293D is designed for a maximum continuous current of 600mA per channel. From your specs, your motor will draw more current than that even at 6V, however in my experience this is unlikely to instantaneously burn out the H-bridge. It may run hot or have a shorter lifespan if you plan long-term use, but if you just need a working demonstration for a science project and will only use it for short periods of time, it should be fine. If you need to use it for longer periods then I would look into a motor driver board or shield for the Arduino that can handle more current.