stratohunter
10 mW
- Joined
- Apr 12, 2022
- Messages
- 34
So I ran into some very rare issues with my 52V TSDZ2 and OSF 1.1.0 after 6 months and 1200km on it. Last time when I was riding up a small hill, the engine started to give horrible scratching and colliding noises all of a sudden. Although it did not quit working, I switched it off immediately and pedaled home. Initially I thought it was the blue gear, until I opened it up and found it in perfect shape. There was even no obvious sign of wear on it. Then after two days of debugging I finally narrowed it down to the BLDC motor. I took the BLDC motor apart and to my surprise the culprit was a displaced magnet, which had slid so much axially and radially, that it was rubbing against the stator.
I also discovered at least half of the 16 magnets were more or less moved. You can see it in the first image below, notice the gap between some of the magnets and the iron rim. When I was pulling the rotor out, one magnet slid off the rim right away, being the one shown in the second image below. I glued it back with epoxy and put everything back for the engine, problem solved. My engine was back to working, for the next 20 miles, until probably another magnet had just slid far enough to touch the stator. Now the engine is making scratching noises again, though not as severe as the first time, and no noticeable loss of power output. It's still ridable but who knows what will happen after another 20 miles.
I can glue all magnets onto the rotor rim firmly if I want, but I'm a bit curious why I keep running into this issue. I had only exceeded 700 watts once, in a test ride 2 months ago in freezing weather. For most of the time I stayed under 600w (I set 12A for motor current in my trips), and the weather had almost never exceeded 10 degC or 50 degF here. I saw brownish stuff on the rotor but doubt whether I really had the chance to overheat it? Afterall, the weakest blue gear was in perfect condition at the moment the BLDC motor failed. Also, I often pedal beyond 90 rpm, could this overrev the motor and throw the magnets out?
I really hope this little engine can come back to work again, like in the past 6 months. It was a joy to ride, when not making troubles.
I also discovered at least half of the 16 magnets were more or less moved. You can see it in the first image below, notice the gap between some of the magnets and the iron rim. When I was pulling the rotor out, one magnet slid off the rim right away, being the one shown in the second image below. I glued it back with epoxy and put everything back for the engine, problem solved. My engine was back to working, for the next 20 miles, until probably another magnet had just slid far enough to touch the stator. Now the engine is making scratching noises again, though not as severe as the first time, and no noticeable loss of power output. It's still ridable but who knows what will happen after another 20 miles.
I can glue all magnets onto the rotor rim firmly if I want, but I'm a bit curious why I keep running into this issue. I had only exceeded 700 watts once, in a test ride 2 months ago in freezing weather. For most of the time I stayed under 600w (I set 12A for motor current in my trips), and the weather had almost never exceeded 10 degC or 50 degF here. I saw brownish stuff on the rotor but doubt whether I really had the chance to overheat it? Afterall, the weakest blue gear was in perfect condition at the moment the BLDC motor failed. Also, I often pedal beyond 90 rpm, could this overrev the motor and throw the magnets out?
I really hope this little engine can come back to work again, like in the past 6 months. It was a joy to ride, when not making troubles.