eblc1388
Active Member
I think the biggest problem with designing the motor controller is controlling the speed when there is a large "lump" of washing in there. The drum needs a hefty push with a load of water and wet washing in the bottom to get going then you need to reduce the speed otherwise the washing won't tumble and will just stick to the sides.
The "universal motor + speed control feedback" excels in this case, regardless of how many washing there is. No difference in performance observed between drum empty and fully loaded.
Likewise with the spin cycle, if you spin the washing up too fast, the washing clumps and the machine shakes itself to bits. You need an algorithm which will try and spread the washing evenly around the drum before spinning - if there is too much vibration, try again and again and again .......
Exactly. That was called the "distribution" phase where clothing is distributed evenly around the drum before the drum speed actually rams up. It's about several rpm per second and holds there for a about 15 seconds to also let some of the water to spin/drain off. My washing machine did not have vibration sensor and it will not retry if vibration is excessive. The phase angle control using the universal motor+speed feedback is normally very smooth.
However, it is a big problem if the washing load is small and in this case vibration is excessive during spin dry.