Bowthruster not thrusting

I had the exact problem on my BTR 185 stern thruster. Broken brushes and a twisted bracket. I had to remove the rear assembly from the motor refurbish the bracket and new brushes. I never knew what caused it but it happened mid season so was not from sitting idle. I believe over current caused the problem so I now limit use. I will say that my 8.0 kW bow thruster has never had this problem even after periods of extended use. The 4.3 kW motor is simply not up to par. 

Yes there is a thermal switch but it won’t protect the brushes and and the commutator pads from repeatedly arcing. Thermal overload takes a bit of time. Over current can do damage quite quickly. 

Mine was in worse shape and is now running well. The pads can be resurfaced with 500 grit paper and the rest is just carbon build up from arcing. However, since yours is at the the bow, it will to never be up to the task. The 6.3 kW motor is a drop in upgrade if you can get it. My advice is refurbish the existing motor and concede to minimal use, or spend your money on the 6.3 kW unit. SVB Germany is your best source.

Two 80Ah batteries store about 2kWh of energy (assuming you connect them in series to get 24V) so you are looking at about 20 min of continuous run of 6.3 kW motor, not much difference from 4.3kW motor which will discharge them all the way to 0 after 30 min of continuous run. If you want to keep 50% reserve capacity, then its 10 and 15 min respectively 

Very timely thread. I have a bow thruster on my new to me Hanse 385. It is showing the same kind of issue that was on the video in the first post. I have taken out the motor. Pics of the motor below.