One Thruster (T200) not getting power / working properly

I have a BlueROV2 R1. One of the T200 thrusters jerks through its rotation rather than spin at speed. I have replaced the thruster and have the same issue. I have checked continuity of all three phases/lines to the motor and everything seems okay (but my knowledge beyond checking continuity for how these work is limited). Everything seems to be the same as it is for the other thrusters.

Any suggestions on next steps?

This seems the most relevant troubleshooting, but I have eliminated these problems:

The propeller tries to move but does not spin correctly.

  • All three thruster wires may not be connected to the ESC motor wires correctly. Check that there is a good connection between the three ESC motor wires and the thruster wires.
  • There may be a broken thruster wire or a short between thruster wires. Check the resistance of each thruster wire pair (blue wire/green wire, blue wire/white wire, green wire/white wire) using a multimeter. Each thruster wire pair should have the same resistance within 0.1-0.2ohms or so. If there is no continuity between a pair, or one pair has significantly higher resistance, the thruster is defective.
  • Try to rotate the propeller by hand, it should spin freely. If it is difficult to rotate, disassemble the thruster and check for damage or blockage.

If there is anyone out there - I am sure this is a simple “you need to replace your X” problem… can you help?

Hi Folks, sorry to beg, but I have some outreach I am doing with kids on Tuesday and would really like to have this running. I am a little concerned about really tearing the thing apart without some confidence in the problem. If anyone had some time to troubleshoot with me over the weekend I could compensate for it?

I have a space ESC, but I think it is unlikely to be the problem?

I am as new as you are to bluerov, but I have 9 custom drones ESC when bad can do odd things I had an quad that would flip out the sky, found that throttle over x% shutdown the esc. Had another quad hit a tree the motor wouldn’t arm esc. Trust my I know its kind of a pain to open the WTC if you look at my post you will see I stuggled with a user error and had to open mine many times, but if you have an esc why not test and see or of you dont want to rip out the esc simply swap a motor from one esc to the other remembering which one and retest.

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Hi @mdares,

Apologies for the delay on getting to this - it’s a challenge to get through all the forum posts at the moment. In general I’d recommend reaching out to if you need support on something that’s broken or not working as expected, especially if it’s time-sensitive and the community and I aren’t responding quickly.

This makes it seem unlikely to be a thruster issue, in which case it’s presumably an ESC issue, but could also conceivably be an issue with the connections to and from the ESC, or with the signal being sent to the ESC (e.g. the output pin could be malfunctioning).

Given you know your other ESCs and thrusters are working I’d recommend swapping the signal wires from one working ESC and the one that’s not working. If the previously working ESC stops working and the poorly performing one gets fixed then it’s most likely a flight controller output/pin problem. If instead the behaviour is the same just with a different motor order then it’s definitely an ESC or wiring issue.

If you’re running a standard firmware then an output problem doesn’t make much sense, in which case it’s likely worth connecting to a different pin and assigning the corresponding SERVOn_FUNCTION parameter to the MotorN value of the one that’s not working.

If you’ve discounted an output issue, and end up trying this out and it doesn’t help, then there’s some kind of wiring issue between the ESC and the thruster - likely due to a loose connection that’s intermittently dropping out or something.

Thank you Eliot - that was the shove I needed. Switching the pins still had the same motor misfiring. I replaced the ESC and everything looks good now. Interesting to see that the motor with the new ESC responds differently than the ones with the original R1 ESC’s.

Great to hear! :slight_smile:

Odd - the changeover was well before my time at BR, but as far as I’m aware they should be a drop in replacement (unless by “responds” you just mean the startup sounds):

I can confirm new ESC is NOT compatible with old version.
Doing an upgrade to heavy using a mix of old and new ESC’s did not go well.
The new was spinning with half the speed.
Had to swap all ESC’s.

Interesting - I only noticed that it is actively breaking the on turbine with the ESC on it and a bit of a difference in the way they spin up. If I am seeing a power issue - good to know. Wonder if I will be able to account for it in the motor settings in QGroundControl.