Tesla inventions we still use

Keith Wilson - Electrical engineer

Following on our previous features on the life and work of Nikola Tesla, today we’re suggesting a top five of Tesla’s most important inventions. After much debate here at the Megger offices, the team has come up with five inventions that have had a great impact on modern technology.

1. Alternating current
A unanimous decision has been reached regarding Nikola Tesla’s research and contribution to the development of alternating current (AC) technology. Although he did not invent AC, Tesla’s devices made AC applicable for widespread use, helping to electrify the dark world he grew up in.

Image source:wikimedia

Developed as a safer and more reliable alternative to Edison’s direct current, AC has the outstanding advantage that the voltage of the supply can easily be increased or decreased with a device that has no moving parts: the transformer. This made it much more feasible to send large amounts of energy over a large area.

2. Wireless transmission
In 1895 Tesla’s New York lab burned down destroying years’ worth of notes and equipment. Tesla relocated to Colorado Springs for two years, returning to New York in 1900. He secured backing from financier J.P. Morgan and began building a global communications network centered on a giant tower at Wardenclyffe, on Long Island.

Image source: wikimedia

The Wardenclyffe Tower, built in 1901, was an early wireless station designed to transmit messages, telephony and even images across the Atlantic and to ships at sea. The tower’s technology was based on Tesla’s theories of using the magnetic properties of the Earth to conduct the signals. While Tesla only achieved limited success, there’s no doubt that his work provided an important impetus for others active in the field, including Marconi.

3. “A powerhouse in a hat”
Tesla is also credited with developing the disk-turbine rotary engine, which he called a “powerhouse in a hat”. The first version developed 110 h.p. at 5000 RPM and was less than ten inches in diameter. Tesla believed larger turbines could achieve double that power.

Image source: By Ctac (Own work) [CC BY-SA 3.0], via Wikimedia Commons

The disk-turbine rotary engine runs vibration free. It is cheap to manufacture because nothing but the rotor bearings needs to be fitted to close tolerances. If necessary, the rotor can be replaced with ease. Turbines can run on steam, compressed air, water, gasoline, or oil and are used in everything today from jet engines to hydroelectric power plant.

4. ‘The shadowgraph’
German scientist Wilhelm Conrad Röntgen discovered, as early as 1895, a mysterious energy that he called X-rays which allowed him to take a picture of the bones in his wife’s hand. In the first picture he produced using this technique, you can see the bones in her hand and the wedding ring on her finger, which was extremely revolutionary at the time!

Although Röntgen is usually acknowledged as the father of modern radiology, there is some evidence that Tesla knew a little bit about X-rays before Röntgen made his research public. Tesla’s own research was stopped when a fire destroyed his lab in 1895, shortly before Röntgen went public with his discovery.

So when Röntgen published his findings and the picture of his wife’s hand, it helped inspire Tesla to create his own X-ray machine using a vacuum tube, which produced pictures that he called shadowgraphs. Tesla is considered the first person in America to take an X-ray picture, having produced a shadowgraph of a foot with a shoe on it.

He sent it with a letter to Röntgen, congratulating him on the discovery. Röntgen, in return, wrote to Tesla commending him on taking a remarkably clear shadowgraph. Shadowgraphs played an important role in the development of X-ray machines, few of which were, in the early days, able to produce an image as clear as Tesla’s.

5. Tesla’s legacy
But perhaps the most important legacy Tesla has left the world doesn’t come in the form of an electrical device or some clever technology. Tesla’s 700 patents have paved the way for other generations of inventors, enabling them to create and find answers to our life’s most diverse challenges.

One such promising inventor is 13 year-old Max Loughan from the USA who recently came up with a ‘free energy device’ that resembles Tesla’s coil and operates on some of the same principles described by the electric visionary. The device is rather simple, harvesting electromagnetic energy from the atmosphere, then converting it to direct current which can be used to power small electrical devices.

Although the concept of ‘free energy’ may still sound utopic, it is imaginative people like young Max who are leading today’s quest for safer and more effective energy sources. And frankly, we should all be thankful to Tesla for his immense legacy!