Where and why is a 277VAC input used in the USA?

The AC power supplied to and used by household and commercial buildings in the USA is primarily 120VAC.  This voltage is suitable for most electrical and electronic equipment in the home or office, but for the higher power requirements of electric driers, air conditioning and electric ovens, 208VAC or 240VAC is also available.

In larger industrial properties, in addition to 208VAC and 120VAC, 480VAC three-phase is supplied to the building in a "WYE" (or Y) configuration.  Using 480VAC three-phase to power larger electrical equipment like fork lift battery chargers and heavy machinery allows less current to be drawn by the load, thus enabling the use of lighter gauge wire.  In addition, the current is balanced equally in each phase.  This power disctribution scheme improves power distribution efficiency.

This blog article from TDK Lambda delves further into this topic, explaining how 277VAC comes about and how it’s used in industrial applications.  The article also highlights a few of TDK Lambda’s power supply solutions that are well-suited for use in 277VAC input applications.  You can read the entire blog post here: Where and why is a 277VAC input used in the USA?

For more information about TDK Lambda’s products, or to discuss your current power design, please contact Cover 2 Sales for assistance!



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