Load Bus Synchronization (LBS) is designed to improve the redundancy and reliability for N+1 redundant system. In normal situation, UPS1 and UPS2 work equally with its own load, when one UPS goes failure, the system transfer to another UPS without interruption. And the LBS is used to synchronize the output phase of two UPS.

LBS is applied in three mode: LBS mode, parallel LBS mode and slave LBS mode.