A rare Telechron Type A Master Clock resides in a display case at the Columbus Powerhouse. Operators there used the clock to keep the official time for the State of Nebraska until 1950.
The Master Clock was used to control the frequency of the alternating current to an even 60 cycles per second. This regulation facilitated the rise of the electric clock in homes across the country.
By 1941, the Warren Telechron Company produced about 3 million clocks annually.
The Magic of Telechron Clocks
Courtesy of Rick Wilson, swirledshrub.com
It was 1916, and Henry Warren had an interesting problem.
Warren had invented an electric clock powered by a compact, self-starting, synchronous motor. “Synchronous” was the best part—that meant that the motor rotated precisely in step with the 60 cycles per second of the predominant alternating current in the United States. Sixty Hertz, to use the proper units.
In essence, Warren’s motors “knew” that one second equaled sixty oscillations of their power source. The very electricity that powered his clocks defined what one second meant.
Except that in 1916, no power company in the United States provided regulated 60 Hertz power.
That may have been the standard to which power companies aspired, but their product varied considerably. From minute to minute, from second to second, the current frequency varied. It was the generators at the power plants. They ran within a wide range of speeds, not at only one precision maintained speed. For a light bulb, this didn’t matter. A light bulb would glow pretty much the same at 43 Hertz, 67 Hertz, 54 Hertz … the exact frequency of that storied sine wave didn’t make too much difference to a light bulb filament.
But with that kind of frequency variation, one couldn’t make a proper electric vacuum cleaner. Nor an electric clothes washing machine. Nor an electric sewing machine, the most sophisticated consumer product on the planet at that time. Nor precision medical equipment.
Back to Henry Warren’s problem—if the alternating current power supply wasn’t precisely tuned to sixty cycles per second, his theoretically fully functional electric clock design was inaccurate and therefore absolutely useless.
Henry Warren solved this problem by developing a governor, which he called the “Master Clock,” which could control the current delivered by a power company through a feedback mechanism.
Warren Master Clocks were straightforward in their design and use. They were quite beautiful machines, actually. They looked rather like the grandfather clocks of their day, pendulums and all. But instead of a single clock face, they had three, vertically arranged at the top of their tall wooden cases.
The bottom dial, with twelve hours and the traditional hour and minute hands, was driven by a highly accurate mechanical movement, pendulum included. The center dial was divided into five one minute sectors, and had two superimposed hands, one black, the other gold. The black hand was driven by that splendid mechanical movement. The gold hand was driven by a synchronous motor, tied into the power generators of the plant. A synchronous motor that turned at the exact same frequency of the alternating current that powered it.
Both the black and the gold hands of that middle dial moved as second hands, making a complete revolution around the dial in five minutes.The upper dial was a backup, matching that middle dial, with just one gold hand also driven by a second synchronous motor whose hand also moved around a matching 5-minute dial. This backup stood ready in case the main synchronous motor should fail, or for when it needed routine service.
The Warren Master Clock was intuitive. The power plant generators were running at 60 Herz when both the black and gold hands on the main dial were super-imposed upon each other, moving in unison around their dial. Any deviation was easy to see and would let the technicians know how much to adjust the generators in order to keep the line current at 60 Herz.
Warren took his Master Clock to Boston Edison, which at first resisted his idea. There was really no market pressure, clamoring for electric clocks, upon the power company, since such clocks didn’t exist yet outside Warren’s lab. But there was another market pressure developing: radio. Radio more than any other appliance demanded precisely regulated AC current. Radio, plus all the other aforementioned consumer technologies, influenced Boston Edison to give Warren’s Master Clock a try.
And they were delighted with the results.
Top: The nameplate from Loup Power District’s Warren Telechron Master Clock. Bottom: Historical records show that Loup’s clock was initially used at Muscatine Electric Light Company in Muscatine, Iowa. Loup acquired the clock sometime in the late 1930s. Courtesy of Ashland (Mass.) Historical Society.
By the mid-1920s over 400 Warren Master Clocks had been manufactured and installed in power plants around the United States. They sold for $400 apiece, some $9,200 in 2018 dollars. They paved the way for consumer and commercial electric appliances as we know them today. They also paved the way for Henry Warren’s electric clocks.
For his company, at first called the Warren Clock Company, Warren eventually chose the name “Telechron,” from the Greek suggesting “time over a distance.” Appropriate, considering the vast web of electric transmission wires that were woven over most of the U.S. in less than a decade.
As Warren geared up Telechron to manufacture electric clocks in quantity, a battle was being waged between Thomas Edison’s vision of direct current versus General Electric’s method of alternating current. GE and AC won out and, with an obvious desire to maximize the uses to which electric current could be put, expressed an interest in the nascent Telechron brand. Warren sold a 49 percent interest to GE in 1919, maintaining a controlling 51 percent interest and serving as president of the company.
As the U.S. economy boomed after the end of World War I, Telechron really took off. According to Jim Linz’ definitive book, Electrifying Time, sales of Telechron clocks “increased from 87,000 in 1927 to almost 4.3 million in 1937.” Keeping in mind that the Great Depression started with the Crash in October 1929, that is an especially impressive achievement!