Dolphin s200 Carbon Brushes

[Foosman]

It has nothing to do with the magnets.

You connected the wires wrong. In these types of DC motor, the current flow direction determines which way the motor will spin. Usually you’ll see a bit of colored nail polish or marking somewhere on the end cap where the brushes connected to the external wiring. That denotes (+) or (-) voltage. When you disassemble these motors, you need to be mindful of how the wires are connected, they are not interchangeable.

Swap the wire connections and it will spin the right way.

It is not possible to swap the positive and negative polarity on the motor due to miss wiring, but it is possible if you do not put the brush cap back on correctly...see my response below.

 

[Foosman]

Hi Foosman, I also changed the carbon brushes a couple of weeks ago but recently realized that the impeller is turning backwards. How do you put the magnents in the correct position?. Sorry but I am not familiar with the "permanent magnets in the motor housing 180 degrees rotated" concept. Could you please explain?.
Thanks for your help!

You need to disassemble the motor assembly just like you did when you replaced the brushes (remove the 2 screws) and you need to rotate the end cap that's holding the brushes 180 degrees and reassemble.

Below is a photo I got off eBay. Notice the silver sticker on the motor case. Let's call this the top of the motor. Note the orientation of the red/black cable on the end cap is to the right. Now if you disassembled and rotated the end cap 180 degrees and reassembled then the red/black cable would now be on the left side. This is what I mean by rotating the end cap 180 degrees.



The reason it is spinning backwards is that inside the motor housing (the round black case) are magnets, a north pole on one side and a south pole on the other side. The brushes you replaced are providing power and one brush is positive (+) and the other negative (-) polarity. The orientation of the brushes relative to the magnets is important. If you assemble it rotated 180 degrees, the current changes relative to the magnets and it will spin the other direction as the force from the electric field changes direction.

 

[JoyfulNoise]

It is not possible to swap the positive and negative polarity on the motor due to miss wiring, but it is possible if you do not put the brush cap back on correctly...see my response below.

You can on the impeller motor. On my old S300, the wiring can be swapped and if you do that you’ll get the otor spinning in the wrong direction. Perhaps they’ve updated the motors since my 2016 model and do the wiring differently. Either way, polarity and orientation matter with these motors.

 

[JoEuGro]

You need to disassemble the motor assembly just like you did when you replaced the brushes (remove the 2 screws) and you need to rotate the end cap that's holding the brushes 180 degrees and reassemble.

Below is a photo I got off eBay. Notice the silver sticker on the motor case. Let's call this the top of the motor. Note the orientation of the red/black cable on the end cap is to the right. Now if you disassembled and rotated the end cap 180 degrees and reassembled then the red/black cable would now be on the left side. This is what I mean by rotating the end cap 180 degrees.

View attachment 603751

The reason it is spinning backwards is that inside the motor housing (the round black case) are magnets, a north pole on one side and a south pole on the other side. The brushes you replaced are providing power and one brush is positive (+) and the other negative (-) polarity. The orientation of the brushes relative to the magnets is important. If you assemble it rotated 180 degrees, the current changes relative to the magnets and it will spin the other direction as the force from the electric field changes direction.

View attachment 603746

Very clear Foosman!!. Thanks a lot for the explanation. I will do the changes today and let you know the results.
Regards!