Wednesday, January 05, 2011

Percy Spencer - the innovator of the microwave oven and other things

Have you ever heard of Percy Spencer? This is the person who noticed magnetrons generated heat that could be used to cook food. He was standing near a magnetron, when the candy bar in his pocket melted. He then started putting things together and created the first oven, called a Radar Range.

Besides his numerous innovations and inventions, Percy Spencer only had an education until the age of 12. So, what was his secret? Persistence = yes, Innovation = yes, but also curiosity about how things worked. He was basically a self educated man, who through trial and error and reading, created one of the most helpful home appliances in history.

Read on, his story is interesting because he did not get all the "tools" by getting a formal education.

Early in World War II, British scientists developed radar to detect Nazi Luftwaffe planes at night.
The system helped thwart devastating raids. But they couldn't perfect its crucial magnetron, which converts electrons into microwaves. Britain asked America for help, which led to a meeting with Percy Spencer, an engineer at defense manufacturing firm Raytheon. Spencer, a man with only a grade school education, listened as British scientists described their magnetron production, a process he said was awkward and impractical.
The British trusted Spencer to the point they let him take its most valuable secret weapon home.
Smart move. Within days, Spencer came up with radical changes that simplified manufacturing and improved its performance.
"He had a reputation for thinking outside the box," said Rod Spencer, a grandson of the inventor who would develop the microwave oven. "He was totally driven to create new things and had an intuitive sense for how things worked."

Spencer's Keys

  • Designed radar systems in World War II that paved the way for the microwave.
  • "He was totally driven to create new things and had an intuitive sense for how things worked," said grandson Rod Spencer.
The British method of building a magnetron required the machining, drilling and reaming of copper blocks to accurate dimensions. One slight mistake and it was trashed.
Flippin' Genius
The spark for Spencer's reinvention came from his coins.
"While stacking the coins, the idea came to him how to make the magnetron," said Rod Spencer, founder and CEO of, a developer of automation software.
His grandfather wrote in 1960: "I conceived the idea of stamping out sheets of copper, stacking them with silver separators and putting them through a furnace."
He also swapped out electronic parts with more advanced systems, refining them to make radar systems far more effective in combat.
The result: Raytheon produced 2,600 magnetrons a day, up from 17 per week, with Spencer managing hundreds of people. Raytheon radar systems could detect enemy planes, submarines when they surfaced and German warships at long distances for successful destruction. Raytheon accounted for 80% of the magnetrons produced for the war effort.
For his service, Spencer was awarded a Distinguished Service Medal, the U.S. Navy's highest civilian honor.
His best commercial invention, the microwave, was still to come.
Born in Howland, Maine, in 1894, Spencer was just 18 months old when his father died in a sawmill accident. His mother then left Spencer and another son in the care of an impoverished aunt and uncle.
His uncle died when he was 7, and his formal education ended when he was 12. After working at a spool mill, he learned that a local paper mill was going to use electricity.
Even though Spencer knew nothing about electricity, he signed on to install the system. He learned entirely by trial and error and studied textbooks by night. When the project ended, he was a skilled electrician.
The Titanic's SOS failure and sinking in 1912 added up to a turning point. It dramatically popularized wireless telegraphy operators. One of those hooked was Spencer, who joined the Navy to learn the craft.
To make up for his limited schooling, "I just got hold of a lot of textbooks and taught myself while I was standing watch at night," he said. He learned trigonometry, calculus, chemistry, physics and metallurgy.
By the time he joined Raytheon in 1925, Spencer had a reputation as one of the best electric tube designers who "could make a working tube out of a sardine can," said a Massachusetts Institute of Technology physicist.
In The Know
In a 1958 Reader's Digest article, an MIT scientist suggested Spencer's lack of schooling was a plus: "The educated scientist knows many things won't work. Percy doesn't know what can't be done."
Following the end of World War II in 1945, Spencer wrote about his time at Raytheon, saying, "We found ourselves with zero business in the microwave tube field. It was in this period that I got the idea of cooking with microwaves."
The magnetron device used for radar caused a stream of electrons interacting with a magnet to resonate in a specially shaped, high-powered vacuum tube. The result was microwave radiation.
Hot Stuff
Scientists knew that magnetrons generated heat when molecules reacted to microwave frequencies.
As the story goes, Spencer was at a lab where magnetrons were being tested. As he stood close by one, he recognized that a candy bar in his pocket had melted.
He had an itch to find out more.
At the time, Raytheon revenue was plunging and needed to develop products for the civilian market.
CEO Laurence Marshall pulled together his top engineers. Spencer suggested they should build a microwave oven. He had solved some of Raytheon's greatest challenges. Now Marshall told him to go for it.
Spencer built a box with a magnetron in it and put popcorn kernels inside. In short order the kernels popped. An egg was next. Spencer began using it to reheat his lunches.
The development of the microwave grew from these observations, and in 1947 the first microwave oven hit the market.
The primitive unit was 5 1/2 feet tall, 2 feet wide and deep, and had to be water-cooled. It weighed nearly 800 pounds and cost about $3,000.
Raytheon named the monster the Radar Range. It wasn't a big seller, since it was practical only for restaurants, airline companies and other commercial operations.
Spencer needed help to design and build an oven for the home market. His teammate was Marvin Bock, a young Raytheon engineer who contributed plenty to shrink the size.
Other companies were working on a microwave oven as well. The first such device for the home was introduced in 1955 by Tappan Stove Co. under license from Raytheon. It faced similar problems: too big, bulky and expensive, at $1,300.
Raytheon, with Spencer in the hub, developed a new model in 1964, and in 1965 bought Amana, a developer and marketer of brand-name household appliances. Two years later Amana introduced the Radarange, the first countertop microwave oven geared specifically for the consumer market.
By 1975, sales of microwave ovens exceeded those of gas ranges.
Spencer died in 1970 at age 76 with more than 150 patents to his name.
"He passed away before microwave became popular, so he had no idea it would take off the way it did," said his grandson.
A 1992 survey by R&D Magazine listed the microwave oven as one of the top 30 products that changed our lives, rating No. 2, just behind the personal computer.
Spencer entered the National Inventors Hall of Fame in 1999.

No comments: