Like power supplies, they are used for test systems and test benches or wherever a power supply at a frequency other than the one available is required (e.g., for powering 60Hz devices where the network is 50Hz or vice versa).
![convertitore di frequenza sidial](https://www.sidial.it/wp-content/uploads/2018/02/convertitori_di_frequenza_sidial_0.jpg)
Like power supplies, they are used for test systems and test benches or wherever a power supply at a frequency other than the one available is required (e.g., for powering 60Hz devices where the network is 50Hz or vice versa).