Transistor Museum Oral History Ralph Greenburg "Electric Runabout" Page 2

EARLY TRANSISTOR HISTORY AT MOTOROLA

“DAVE ADLEY”S ELECTRIC RUNABOUT” by Ralph Greenburg

After test drives around his neighborhood and fiddling with different coat hangers Dave was able to drive at least 10 miles before the batteries ran down. He then wanted to test the car on a regular schedule so he arranged with me to drive to my place each work day (about 6 miles), leave the car in my carport with a charger attached, then he would ride with me to work. And the reverse of the above when we went home. This was done for about a month and on the weekends Dave continue to increase the efficiency of his system, until he was confident he could drive all the way from his house to the 52nd. Street plant, about 12 miles.

We arranged with plant security to allow Dave to park the vehicle next to P building where the Application Lab was (in the basement), and connect to an electrical outlet to charge the batteries. Dave tried to increase the mileage range but about 15 miles was the limit.

There were two problems with the coat hanger speed control, it used up a lot of energy and at certain speeds the wire got red hot. So Dave started thinking about a more efficient speed control. Fortunately other engineers working on Industrial Applications had a solution, a high efficiency switch mode power supply circuit using power transistors. We conjured up a "skunk works" project to let Dave use the Applications team build a speed control using the switch mode principals.

This proved quite successful and the range increased to close to 50 miles and Dave could put his electric contraption in the parking lot, just like all the other employees. Having proved that an electric car was possible, if not practical, Dave lost interest and sold the car to another engineer.

During these years a bunch of Application types had an informal Golf league across the street at Papago Golf course. Although we always walked 9 holes after work there were electric Golf Carts available, with resistor speed controls much like Dave’s coat hangers but a little more sophisticated. One day someone asked the manager of the golf shop how often did they recharge the batteries on the carts. He said too often. The next day the same engineer suggested that Applications borrow a Golf Cart from Papago and install a switch mode speed control, similar to Dave’s', which would increase the amount of times the cart could go out before needing a recharge.

Go To Greenburg “Dave Adley’s Electric Runabout”, Page 3

A Transistor Museum™ History of Transistors Publication

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