There have been a number of news reports recently about a startup in Bengaluru called Vimag Labs that has reportedly replaced rare-earth magnets in motors with so-called “virtual” magnets.One such report quoted Manish Seth, the start-up’s CEO, as saying: “We remove permanent magnets, replace them with copper coils, and then through software, we generate magnetic fields inside the motor.”To understand this claim, it helps to first see how electric motors produce magnetic fields and why they use permanent magnets in the first place.Rotor and statorA motor needs a magnetic field to operate. One way to create it is using a permanent magnet. Another is to pass current through copper coils that have been wound around a ferromagnet, temporarily turning it into a magnet. This is called an electromagnet — and it is this approach that the startup has used, instead of permanent magnets.When an electrical machine converts electricity into mechanical motion, it is called a motor. On the other hand, a machine that converts mechanical movement into electricity is called a generator. In both cases, the conversion happens via a magnetic field.
A rotor (left) and stator (right) of an electric motor.
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