What is a station service throw-over switch used for?

A station service throw-over switch is specifically designed to allow operators to switch between different power sources for a station. This functionality is crucial in ensuring an uninterrupted power supply for essential equipment when one source may be undergoing maintenance, experiencing issues, or is otherwise unavailable. By enabling this source change, the throw-over switch enhances the reliability and flexibility of the station's power supply, ensuring that operations can continue smoothly without significant downtime.

In contrast, the other options do not accurately represent the primary function of a throw-over switch. Monitoring voltage levels involves measuring and assessing electrical parameters, which is not a role performed by a throw-over switch. Disconnecting equipment for maintenance is typically managed by circuit breakers or disconnect switches designed specifically for that purpose. Controlling emergency power supplies often relates to backup generators or UPS systems rather than the switching mechanism of a throw-over switch. Thus, the primary and correct purpose of a station service throw-over switch is indeed to facilitate source changes at the station.