Prop running backwards
- Thread starter cncreef
- Start date
The basic issue is that this style of motor is what is termed synchronous and it uses a mechanical system to correct direction, this is why they don't handle repeated off and on cycles well like on wave makers. Almost all AC pumps work this way but with an impeller the direction is not an issue, they can and do start spinning either way and it has no effect. With a prop pump, if the prop spins backwards a stop has to stop it and correct the direction. The stop system seems to not be working so it has to be one of these 3 things and I list them in order of probability. What should happen in a backward spin is the prop lies forward, breaks contact with the electromagnetic field, hits a pair of stops and falls back and like a falling maple seed, it picks up the correct direction and then syncs back up with the coil.
1) The titanium shaft is calcified or the hole in the propeller/magnet so the prop cannot smoothly move back and forth to hit the stops. Only cleaning by soaking in vinegar is needed, it should be disassembled first.
2) The ends of the propeller are worn or broken so it can clear the stops. A new drive unit is needed. This will usually be due to a higher frequency of off and on cycles.
3) The stop tabs are broken, this is pretty rare but on the inside of the crosshatch on the output you will see inward facing tabs to stop the propeller. It is fairly extreme for these to break and usually is limited to damage caused by modifying the front housing.
1) The titanium shaft is calcified or the hole in the propeller/magnet so the prop cannot smoothly move back and forth to hit the stops. Only cleaning by soaking in vinegar is needed, it should be disassembled first.
2) The ends of the propeller are worn or broken so it can clear the stops. A new drive unit is needed. This will usually be due to a higher frequency of off and on cycles.
3) The stop tabs are broken, this is pretty rare but on the inside of the crosshatch on the output you will see inward facing tabs to stop the propeller. It is fairly extreme for these to break and usually is limited to damage caused by modifying the front housing.
