Because the power supplied to the resolvers produces no actual work, the voltages used are usually low (<24 VAC) for all resolvers. Resolvers designed for terrestrial use tend to be driven at 50–60 Hz (utility frequency), while those for marine or aviation use tend to operate at 400 Hz (the frequency of the on-board generator driven by the engines). Aerospace applications utilize 2,930 Hz to 10 kHz at voltages ranging from 4 VRMS to 10 VRMS. Many of the aerospace applications are used to determine the position of an actuator or torque motor position. Control systems tend to use higher frequencies (5 kHz).