The N+1 UPS configuration is mainly designed for computer servers used in businesses. This configuration ensures a backup UPS is available in case the primary UPS fails to function properly during a power outage. The three main types of N+1 configuration are as follows:
Isolated Redundant Configuration
While an isolated redundant configuration is considered as an N+1 system, it does not have a paralleling bus and the UPS modules may have different capacities. Power goes through primary UPS device in this setup while the secondary or the isolation UPS is connected to the main UPS to act as backup in case the primary UPS does not work. When the main UPS fails to function properly, the secondary of isolation UPS devices takes over and provides backup power when the main source of power goes out.
The parallel redundant configuration features UPS devices positioned parallel to each other. The UPS devices in this configuration should have the same capacity and share an output bus. In addition, it is advisable to have UPS devices with the same brand for this configuration. When one UPS device in this configuration does work as it should, power will be transferred to the other UPS devices.
Internally “Modular” Redundant Configuration
An internally “modular” redundant configuration features a battery that is connected to each UPS device. This configuration features a battery system connected to all UPS devices. The UPS devices are connected to a common output bus. When one UPS device in this setup does not work properly, the other UPS devices ensure the battery system continues to function. But, the entire system may be affected if the battery needs to be replaced in this configuration.