Uninterruptible Power Supply - Automatic And Static Transfer Switches
December 10th, 2009 | by switch |
Robin Koffler asked:
Automatic Transfer Switches (ATS) are designed to provide resilience in power continuity planning and uninterruptible power supply (UPS) implementations below 10kVA, where UPS cannot be operated in parallel.
Static Transfer Switches are relay-based and can be used in place of PDUs (Power Distribution Units) for plug-and-play loads. Care has to be taken with such devices to ensure a single-point-of-failure is not introduced on the output side of the uninterruptible power supply. Each device is fused or protected by a circuit-breaker and should it open or rupture the load could potentially be dropped.
Automatic Transfer Switches contain two ac input power sources (A) and (B). One possible mode of operation is that Power source (A) can be supplied from the output of a UPS and (B) from a mains power supply. Another is that both (A) and (B) are supplied from two separate uninterruptible power supply outputs. Another alternative is that both are supplied from two separate mains power supplies.
When one of the power supplies fails, the load/s are automatically transferred to the second. When the two supplies are in phase with one another, the transfer is instantaneous.
In addition, an Automatic Transfer Switch can provide protection against load short—circuits, the ability to switch its output power connections on and off remotely (over a network) and load measurement locally via an LCD or built-in sub-D type communications port. ATS can also be hardwired for higher operating power.
This article was compiled using information available in The Power Protection Guide – the design, installation and operation of uninterruptible power supplies (ISBN: 9 780955 442803). By Robin Koffler and Jason Yates of Riello UPS.
network profile switch
Automatic Transfer Switches (ATS) are designed to provide resilience in power continuity planning and uninterruptible power supply (UPS) implementations below 10kVA, where UPS cannot be operated in parallel.
Static Transfer Switches are relay-based and can be used in place of PDUs (Power Distribution Units) for plug-and-play loads. Care has to be taken with such devices to ensure a single-point-of-failure is not introduced on the output side of the uninterruptible power supply. Each device is fused or protected by a circuit-breaker and should it open or rupture the load could potentially be dropped.
Automatic Transfer Switches contain two ac input power sources (A) and (B). One possible mode of operation is that Power source (A) can be supplied from the output of a UPS and (B) from a mains power supply. Another is that both (A) and (B) are supplied from two separate uninterruptible power supply outputs. Another alternative is that both are supplied from two separate mains power supplies.
When one of the power supplies fails, the load/s are automatically transferred to the second. When the two supplies are in phase with one another, the transfer is instantaneous.
In addition, an Automatic Transfer Switch can provide protection against load short—circuits, the ability to switch its output power connections on and off remotely (over a network) and load measurement locally via an LCD or built-in sub-D type communications port. ATS can also be hardwired for higher operating power.
This article was compiled using information available in The Power Protection Guide – the design, installation and operation of uninterruptible power supplies (ISBN: 9 780955 442803). By Robin Koffler and Jason Yates of Riello UPS.
network profile switch
