Dynamometer for ROV motors?


#1

Hello,

I am doing some research on ROV motors and propellers. Full disclamer: I am a recent M.Sc. Mech. Eng. graduate, and a colleague and I designed and sell a [ dynamometer][1]. The beta units are available since the end of August.

I’d like to know a few things…

  1. How important is range and power for ROVs? Is there any use in improving efficiency of the prop/motor? Is overheating a problem?
  2. A lot of hobbyist for quads are building thrust test rigs. Have you seen any of that before for ROV?
  3. How well are underwater props characterized? If you know the relative waterspeed and rpm of the prop, is the torque information available? With the RPM and torque, it is possible to find the optimal motor for the task.

I know quite a lot about motor testing, and I will be available to answer questions here.
Thanks,
[1]: https://store.rcbenchmark.com/


#2

Hi Charles:

Interesting link. I didn’t see a price on the website- can you tell us how much this costs?

Optimizing the propeller/motor/ESC combination is very important on the ROVs. Here at OpenROV, we have two different test rigs that we use. One is a propeller test rig that sits in our test tank and measures propeller thrust at various throttle settings, recording voltage and current as well. The second is a dyno that is used for ESC/motor development. That one is still in an early development phase, and a pre-made dyno, similar to what you have, might be useful, or even just using your instrumentation/software on the existing dyno that we have.

I’m going to be at OpenROV later today, I’ll see if I can’t take a photo or two of our current motor/ESC dyno.

-Walt


#3

I would love to see pictures of your dynos! Do you mesure torque, to obtain efficiency data? We started with a custom dyno too, when we were developping a micro-drone.

Right now, our tool is 495 USD. We have 1 or 2 beta units left.
You can use your own load cells with our data acquisition board and software. It would require small modifications to the safety limits.


#4

Hi Charles:

No, we don’t measure torque, as we haven’t found an easy way of doing so. So while we don’t have absolute efficiency numbers, we are able to measure relative efficiency changes.

On our in-water thrust test rig, we record throttle setting (PWM length), voltage, current, prop RPM, and prop thrust.

-W


#5

Thanks for your help.