Which load bank control is used to check voltage between phases of generator output during three-phase operation?

The volts select switch is specifically designed to monitor and measure the voltage between phases of the generator output during three-phase operation. This control allows operators to select and display the voltage on each phase individually, which is essential for ensuring the generator is functioning correctly and that the voltage levels are balanced across all phases.

In three-phase systems, it is critical to verify that all phases are operating within the desired voltage range, as any imbalance can lead to issues such as increased wear on equipment, decreased efficiency, or even failure. By using the volts select switch, operators can gain insight into the performance of the generator and make necessary adjustments or decisions based on the readings observed.

The other options relate to different functions or controls that do not directly serve the purpose of measuring phase voltage during operation. Consequently, they do not fulfill the specific requirement of checking voltage between phases effectively.