BROV2 Heavy thruster not spinning freely

Performed a pre-mission system check today and had a thruster malfunction. It wouldn’t turn at first when using the controller, it was very difficult to turn by hand also. I assumed that I had some string or fishing line jamming the thruster but after disassembling and reassembling the thruster there wasn’t anything, it started working intermittently but still wont free-spin like the others. There didn’t seem to be much salt build-up on the bearings or anything else. I don’t imagine it is a motor controller issue since it was physically difficult to turn at first but now isn’t…
I will email a video if you like.
Update: tore into the electronics pressure vessel and noticed the MCU terminal block for this thruster is melted. Not sure if it happened before this morning or if I overloaded it while trouble shooting this morning…

@AlaskaSubmarine We have a troubleshooting guide for the T200 here. Let us know what you find.

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Update: tore into the electronics pressure vessel and noticed the ESC terminal block for this thruster is melted. Not sure if it happened before this morning or if I overloaded it while trouble shooting this morning…

Here’s where to get replacement 3 position terminal blocks: WECO 302-HDS/03

Thanks, I just bought 10 of them. Unfortunately they aren’t going to be here for a week or two. I’m going to have to butt solder or splice them with heat shrink…so I can get this working today.
Incidentally, all the phases on the motor core tested at 0.4 ohms.

@AlaskaSubmarine This was probably caused by a weak electrical connection between the terminal block and the wire (loose terminal), leading to higher resistance in the connection and increased heat. When you do use the terminal blocks again, make sure to get a secure connection, and watch your draw. These things are not rated for continuous use with the ROV at full output power.

Fixing the connection at the terminal block resolved the issue. I have more blocks inbound from the source you posted.
I didn’t want to crimp or solder butt splices in because I don’t want to lose any wire length so I cut apart the melted terminal block and just used the internal metal section individually. I will be insulating this quick fix and putting it to bed until the new blocks arrive and I have to open the pressure vessel again for something. Thanks!

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