Shane King is a building automation applications engineer for Yaskawa America Inc. He is a 1999 graduate of Lake Superior State University (BSEE) and has 19 years of experience in the drives industry.

In HVAC VFDs, Is 2-Contactor Bypass Really Better than 3-Contactor Bypass?

Both are safe and reliable, and neither is superior or inferior to the other

Shane King

February 20, 2019

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Since as early as the 1990s, there have been questions, discussions, and application notes on the topic of using a 2-contactor bypass or 3-contactor bypass with variable frequency drive (VFD) configurations.

Another Tool in the Tool Box—How UA Members Are Training and Using 3D Solutions in Piping Projects

In the summer of 2014 the United Association (UA) started a new course to teach their membership the use of laser scanning equipment and related software to create highly accurate three-dimensional point clouds of existing buildings and mechanical systems for the use with BIM applications. Pat Ramirez and Erik Lambrecht were tasked to create the new course which lead to a partnership with FARO.

Ensuring Total Power Backup System Availability – Maintenance and Testing

While the basic concept and need of backup power systems has not changed, the increased likelihood of power outages has put greater reliance on backup power systems, making the their reliability more important than ever. When a utility outage occurs, the backup generator is expected to immediately start and support the load; however, even the best emergency backup power system, utilizing the highest-quality equipment, can be rendered useless if not properly maintained.

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Shane King

ARTICLES

In HVAC VFDs, Is 2-Contactor Bypass Really Better than 3-Contactor Bypass?

Engineered Systems Magazine

2019 September