LayerZero Granted Neutral Switching Patent

Aurora, Ohio (March 18, 2014) LayerZero Power Systems, Inc. has been awarded U.S. Patent 8,674,555, "Neutral Switching High Speed AC Transfer Switch". The patent invention relates to the transfer of an electrical load from one power source to another power source incorporating a hybrid solid state/mechanical transfer switch. The invention provides the advantages of both a solid state transfer switch and a mechanical transfer switch while simultaneously eliminating the disadvantages of each type of switch.

A hybrid neutral transfer switch in an electrical system is designed to transfer a load between multiple AC power sources. A power source, which includes a neutral connection, may be desirable in certain circumstances to provide voltage and current stability and to support single phase loads connected from one of the three phases to the neutral conductor.

A hybrid neutral transfer switch includes a neutral gate controlled device connected to a neutral input of each of the multiple power sources and a mechanical transfer switch that switches between the neutral input of each of the power sources. During the transfer of power from one power source to another power source, the neutral gate controlled devices are activated and/or deactivated in conjunction with the switching of the mechanical transfer switch from one neutral input to another neutral input.

An STS comprised of solid state phase switches combined with a hybrid solid state/mechanical neutral transfer switch described above eliminates the shortcomings of both the solid state neutral transfer switch and the mechanical neutral transfer switch but has the advantages of each switch. For example, the hybrid switch maintains continuity of the neutral current during the transfer of power. Further, the hybrid switch creates a negligible voltage between neutral and ground at the load location and, thus, essentially eliminating the ground current associated with the solid state switch.

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About LayerZero Power Systems, Inc.: 

LayerZero Power Systems is one of the leading manufacturers of power reliability solutions, providing data centers with Static Transfer Switches, Power Distribution Units, and Remote Power Panels, with an emphasis on safety, reliability, connectivity, and power quality monitoring.  For more information, visit


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