Resolvers offer an inexpensive way to measure axis rotation or for example the rotation of the motor in conveyor lines. In an electric motor the frequency converter can adjust the engine speed using the measurement data of the rotary encoder. The rotation speed can additionally be measured with a contacless resolver or a DC tachogenerator, the voltage produced by which is proportional to the rpm.
Resolvers are widely used in the automotive industry, especially in hybrid cars containing both electric and combustion engine.