I have been working on a project to test for gravitational anomalies. It is a magnetically levitating motorized ring, within a ring shaped frame. It has taken some months for me to develop a robust electronic drive for what is in fact a 2500mm diameter BLDC electric motor with no bearings and no output shaft.
While testing the coils and microcomputer controlled steps for the motor it occurred to me that it may be possible to accomplish my aim of high speed magnetic field rotation with the coils alone. A virtual motor.
The circumferential rotational rate I have been aiming for is about 500 meters per second, hence the large diameter of my levitating rotor. A small diameter of 250mm would require a speed of 33,000 RPM and for me would be an engineering impossibility.
I am using a F & P Smartdrive washing machine motor stator
for this "virtual motor". It is about 250mm diameter, and has 42 coils arranged around the circumference. There are 3 circuits switched consecutively in a loop. The first test has each circuit connecting every 4th coil. The coils simply magnetize and demagnetize in a virtual rotating sequence. Perhaps trapping the BEMF with diodes will be beneficial.
This virtual motor should be able to easily achieve far more than 33,000 RPM.
Initial testing has produced no useful results. The machine runs on 36vdc, and each switching creates a spike of 120vdc. I was adapting the electronics from my main motor, but the mosfets are only rated to 100v and some failed. I have since made a new board with 400v mosfets, but so far have not found time to resume tests.
The new board is much simpler, as it does not require a bridge arrangement. Just one mosfet switches each bank of coils.
This concept may also prove ideal for directional or lateral control of the full size machine I am building. It is possible to mount 2 of these stator units one on top of the other and have the switching counter rotating. It could also be arranged on a single unit, so that half rotate one way and the other half in the opposite direction. There are many variations possible.