Quote:
Originally Posted by mid_life_crisis
I find myself wondering about gearboxes, but I don't see anything capable of spinning at the rpm we need as being reliable or affordable. If you were to try simply offsetting the motor and using a couple of gears to increase the speed, I worry that the side load forces would make the turbine unstable. Could this be overcome by using three smaller motors as the points of a triangle with the turbine shaft in the center? The appropriate sized gears would ramp up the turbine rpm and the three driving gears might support the driven gear of the turbine and help keep it stable while three smaller motors added together could supply the necessary power to spin the thing.
Going further, a plate at each end of the assembly sandwiching the three motors could support a center shaft with a high rpm bearing at each end, allowing you to build it with the drive shaft diameter of your choice in the center. The output speed of the drive shaft would be established by the ratio of the gears. The design is simple and should be fairly rugged.
|
What you described is called a planetary gear. By passing the drive shaft between the motors you have essentially created a quill shaft, which would aid in flexibility to help protect the load and motor from shock loads. An elegant design but I don't think the efficiency losses would make it worth the effort. A 1:2 ratio that gave ~90K rpm would be awesome though. With a motor controller to ramp up motor rpm as engine rpm ramped up the average draw wouldn't be as bad and the connecting rods would stand a chance vs 20 psi at 1500 rpm.