What connection is there between the rotor and armature in a permanent magnet inverter?

The connection between the rotor and armature in a permanent magnet inverter is that they are mounted on the same shaft. In this type of system, the rotor contains permanent magnets, and as it spins, it creates a magnetic field. The armature, typically consisting of windings, is positioned in close proximity to this rotating magnetic field.

This configuration allows the system to effectively convert mechanical energy into electrical energy and vice versa. The synchronous nature of the arrangement means that the armature reacts directly to the rotor's magnetic field without the need for brushes, leading to higher efficiency and reduced maintenance needs.

In contrast, if they were completely separate, additional mechanisms would be required to transfer energy, which would decrease efficiency. Being powered directly from the AC supply does not accurately describe their operational relationship, and although they may use a brushless design, this doesn't encompass the fundamental connection described by the mounting on the same shaft.