This paper identifies benefits that custom engineering services can bring to power transfer switches. It also provides examples of custom-engineered features commonly added to power transfer equipment.
INTRODUCTION
Across the critical power equipment industry, manufacturers offer automatic transfer switches in a wide-range of designs and ampacities. Nevertheless, facilities can require functions and features exceeding those offered by standard transfer switch models. In addition, many facilities can benefit by combining features, accessories, and even systems in ways that are unavailable through standard transfer switch offerings. In these instances, custom transfer switch engineering and manufacturing can integrate additional equipment to optimize functionality and deliver power systems at lower overall installed cost.
PRIMARY BENEFITS
Custom-engineered transfer switches fall chiefly into two categories. The first category adds functions, features, and components that may not be available on standard transfer switches. The second adds value by integrating other source and distribution equipment into a transfer switch enclosure or equipment lineup. The benefits of each category are explained as follows.
Added Features
In normal applications, features, components, and accessories are added to standard transfer switches to meet specific needs. However, when customers require capabilities and features beyond those on a manufacturer’s option list, custom engineering services can produce solutions that meet project specifications. For instance, a customer may request a specific manufacturer’s power meter to match meters used elsewhere in its existing facilities. Likewise, transfer switch lineups can be engineered to provide functions and capabilities beyond those found in standard offerings, such as integrated distribution breakers.
Consolidated Equipment
Transfer switches and lineups can be engineered to consolidate equipment that would otherwise be separately installed. For instance, a standard, full-functioning, Automatic Transfer Switch (ATS) can be provisioned with a separate, breaker equipped, service entrance compartment and additional equipment sections for distribution circuit breakers. When compared to separately engineered and installed equipment, integrated solutions typically reduce the space, time, and overall cost of critical power systems, as follows:
Space: Integrated equipment can be set in adjoining equipment sections or even integrated into different compartments within the same section. Doing so can minimize floor area, wall space, and total volume of the equipment to reduce real estate requirements or facilitate the location of other equipment and systems.
Time: By integrating equipment into a single deliverable product, the design, procurement, manufacture, and shipment of normally separate devices becomes more efficient.
Labor: With separate equipment, devices are installed in different locations and require custom wiring and conduit to be furnished and installed. With an integrated solution, the equipment is deployed with factorydesigned and furnished bus, cable, and control wiring to reduce both procurement errors and installation time. Installation and commissioning is streamlined because the integrated product is assembled and tested before it leaves the factory.
Cost: In ASCO’s experience, the cost of equipment on smaller projects can be variable, with some customengineered equipment exceeding the cost of stand-alone equipment, and some projects realizing savings via integration. On larger projects, there is almost always a savings in direct capital equipment costs. In either instance, the overall cost of specifying, designing, manufacturing, shipping, installing, commissioning, and housing integrated power equipment is typically lower for custom-engineered equipment than for solutions that utilize stand-alone devices.
EXAMPLES OF VALUE-ADDED FEATURES
A variety of features can be incorporated into transfer switches and equipment lineups through custom engineering. Some of the most common are described as follows.
Source Fusing
Transfer switch withstand and close-on ratings are a function of both current and time. If overcurrent protection devices can clear faults more quickly, transfer switches can withstand higher amounts of power before the fault is cleared. Because fuses typically open more quickly than circuit breakers, fuse-equipped transfer switches can provide the highest withstand ratings. The table below compares ratings for representative ASCO transfer switches and shows higher ratings for fused models. (Always refer to directly to the manufacturers most recent transfer switch ratings. Ratings for ASCO Transfer switches can be found in ASCO Publication 1128 - Withstand and Closing Ratings For Transfer Switch Equipment.)
INTRODUCTION
Across the critical power equipment industry, manufacturers offer automatic transfer switches in a wide-range of designs and ampacities. Nevertheless, facilities can require functions and features exceeding those offered by standard transfer switch models. In addition, many facilities can benefit by combining features, accessories, and even systems in ways that are unavailable through standard transfer switch offerings. In these instances, custom transfer switch engineering and manufacturing can integrate additional equipment to optimize functionality and deliver power systems at lower overall installed cost.
PRIMARY BENEFITS
Custom-engineered transfer switches fall chiefly into two categories. The first category adds functions, features, and components that may not be available on standard transfer switches. The second adds value by integrating other source and distribution equipment into a transfer switch enclosure or equipment lineup. The benefits of each category are explained as follows.
Added Features
In normal applications, features, components, and accessories are added to standard transfer switches to meet specific needs. However, when customers require capabilities and features beyond those on a manufacturer’s option list, custom engineering services can produce solutions that meet project specifications. For instance, a customer may request a specific manufacturer’s power meter to match meters used elsewhere in its existing facilities. Likewise, transfer switch lineups can be engineered to provide functions and capabilities beyond those found in standard offerings, such as integrated distribution breakers.
Consolidated Equipment
Transfer switches and lineups can be engineered to consolidate equipment that would otherwise be separately installed. For instance, a standard, full-functioning, Automatic Transfer Switch (ATS) can be provisioned with a separate, breaker equipped, service entrance compartment and additional equipment sections for distribution circuit breakers. When compared to separately engineered and installed equipment, integrated solutions typically reduce the space, time, and overall cost of critical power systems, as follows:
Space: Integrated equipment can be set in adjoining equipment sections or even integrated into different compartments within the same section. Doing so can minimize floor area, wall space, and total volume of the equipment to reduce real estate requirements or facilitate the location of other equipment and systems.
Time: By integrating equipment into a single deliverable product, the design, procurement, manufacture, and shipment of normally separate devices becomes more efficient.
Labor: With separate equipment, devices are installed in different locations and require custom wiring and conduit to be furnished and installed. With an integrated solution, the equipment is deployed with factorydesigned and furnished bus, cable, and control wiring to reduce both procurement errors and installation time. Installation and commissioning is streamlined because the integrated product is assembled and tested before it leaves the factory.
Cost: In ASCO’s experience, the cost of equipment on smaller projects can be variable, with some customengineered equipment exceeding the cost of stand-alone equipment, and some projects realizing savings via integration. On larger projects, there is almost always a savings in direct capital equipment costs. In either instance, the overall cost of specifying, designing, manufacturing, shipping, installing, commissioning, and housing integrated power equipment is typically lower for custom-engineered equipment than for solutions that utilize stand-alone devices.
EXAMPLES OF VALUE-ADDED FEATURES
A variety of features can be incorporated into transfer switches and equipment lineups through custom engineering. Some of the most common are described as follows.
Source Fusing
Transfer switch withstand and close-on ratings are a function of both current and time. If overcurrent protection devices can clear faults more quickly, transfer switches can withstand higher amounts of power before the fault is cleared. Because fuses typically open more quickly than circuit breakers, fuse-equipped transfer switches can provide the highest withstand ratings. The table below compares ratings for representative ASCO transfer switches and shows higher ratings for fused models. (Always refer to directly to the manufacturers most recent transfer switch ratings. Ratings for ASCO Transfer switches can be found in ASCO Publication 1128 - Withstand and Closing Ratings For Transfer Switch Equipment.)
