I have repaired the drive circuits for what could be called a diigital motor".
It used DC pulses to produce a rotating magnetic field to operate an induction motor by switching the pulses to successive windings situated
in a circular pattern surrounding the rotor.
Initially,the drive circuit set up the rotating field at an arbitrary rate,but when it was running,it received feedback from Hall Effect
sensors,indicating the rotor position. This information was then used to stabilise the motor speed.
Although this device used Op Amps & a switchmode regulator IC to perform its marvels,it could be done with virtually all of the circuitry
in the digital domain.
These motors rotated at very high speeds ,& were used to drive "Turbo vacuum pumps" in a Chemistry lab.
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