What is DC Power?

Meet the Connector: DC Power

Direct current is gaining wider adoption, driven by the rise of renewable energy sources, energy storage systems, and battery-powered devices.

The race to electrify the world in the late 1800s was essentially a fierce competition between alternating current (AC) and direct current (DC), each with its own supporters among prominent inventors and businessmen of the day, including Nicola Tesla, Thomas Edison, and George Westinghouse. AC won that initial round, but today, the door has opened for DC power transmission.

AC current forms a sine wave. In addition to the curves shown here, it can also form a square wave or a triangle wave.

AC takes the lead

As the names imply, direct current flows in only one direction, while alternating current periodically changes direction. Edison advocated for DC, but it could not easily be converted to the high voltages needed to distribute electrical power over long distances without loss. To account for this, Edison proposed the installation of numerous small power plants that could deliver power to an end user up to one mile away. This system relied on three wires (+110 volts, 0 volts, and -110 volts) to carry the electricity. The input voltage on the receiving end had to be the same as the voltage generated at the plant. If a different voltage was needed, that would require another generator.

Tesla was a proponent of AC and held many patents that Westinghouse used to develop AC distribution. Transformers could inexpensively overcome the resistance in the wires by increasing the voltage, allowing lower current to travel long distances without power loss. Once it reached its destination, the transformers lowered the voltage to safe, usable levels. This meant one large power plant could provide service to more people and buildings located farther away.

A method of creating and transmitting high voltage direct current (HVDC) over long distances, invented in the 1880s by Rene Thury, a Swiss engineer, proved it could be done. However, the high cost and maintenance still made it impractical compared to AC.

Despite Edison’s extreme efforts to scare people away from AC current, which included electrocuting pets and an elephant to prove it was unsafe, both General Electric and Westinghouse embraced AC and invested in the technology. In 1896, Westinghouse began powering Buffalo, New York, with AC using a hydroelectric dam at Niagara Falls. Europe adopted the AC standard of 220-240 volts at 50 Hz, and the North America standard became 120 volts at 60 Hz.

Adam Tech’s DC-DC converters are designed to effectively convert direct current (DC) from one voltage level to another. This makes them ideal for applications that utilize the cooperation of different voltage levels.

The electronics industry embraces DC

In the 1970s, the invention of semiconductor electronics made it possible to transform current from AC to DC and vice versa. Generated economically with specialized equipment, HVDC lines experience less loss compared to equivalent AC lines over very long distances. HVDC can be used to connect, for example, 50 Hz and 60 Hz AC lines. While in parts of Europe, HVDC lines have been used to connect different countries, HVDC systems are still less reliable and more expensive than AC systems. However, each can potentially be used to its advantage for a specific purpose.

Power transmission for the most part remains AC; however, most electronic devices operate on DC, including all battery charging devices. Energy is wasted in the conversion process and the adoption of numerous devices by consumers, IIoT devices, and the proliferation of data centers led to a huge increase in power consumption and wasteful conversion. Today, improvements in switching systems have made this process much more efficient.

Contactors allow for the safe switching in DC microgrids by keeping high voltages under control and reliably switching electric arcs off. Courtesy of Schaltbau GmbH.

DC microgrids are another development that is making DC systems more reliable and energy efficient. “DC microgrids not only boost operational efficiency but also enable manufacturers to manage fluctuating energy demands with agility and resilience,” wrote Guido Bachmann, director of engineering R&D software and electronics at Schaltbau GmbH, in Energized! Where Connectors and Energy Meet. “Additionally, their ability to integrate with renewable energy sources enhances sustainability initiatives and promotes environmentally friendly practices, all while decreasing reliance on conventional power grids.”

By incorporating distributed energy resources such as solar panels and batteries without conversion losses, DC microgrids can significantly reduce energy costs and environmental footprints. Courtesy of Schaltbau GmbH.

What advantages does direct current offer over alternating current?

Renewable energy sources, such as solar farms, generate DC power, making it very efficient for use in electric vehicles (EVs), telecom devices, and other equipment that doesn’t require conversion to AC. In these applications, DC lowers the risk of outages and increases reliability. EVs can enjoy faster charging, longer battery life, and greater efficiency with DC power.

Projects of all sizes can benefit from the ability of DC power to be scaled up or down depending on need. DC power can be easily stored in backup batteries, which don’t require conversion. This makes it accessible for applications that require uninterrupted power or off-grid systems.

Because DC power provides stable, predictable voltages, it is ideal for sensitive equipment like microprocessors.

Bulgin Buccaneer 900 Series AC/DC circular power connectors are IP66, IP67, IP68, and IP69K rated environmentally sealed circular power connectors designed to provide secure, robust and watertight connections in heavy duty, industrial, and harsh environment applications.

DC power jacks from Würth Elektronik designed to supply direct current (DC) power to devices.

To learn more about the companies mentioned in this article, visit the Preferred Supplier pages for Schaltbau, Bulgin, Adam Tech, and Würth Elektronik.

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