Bruce Carsten: Lifetime Achievement Award Winner

Sep 1, 2006 12:00 PM
By David Morrison, Editor, Power Electronics Technology

First Steps in Engineering

Carsten’s entry into engineering had its origins in his childhood where, at a very early age, he discovered his innate interest in all things mechanical. As a teenager, he developed an interest in electronics after reading about Guglielmo Marconi. Just as important was the influence of his father, whose intellectual curiosity and skepticism inspired these same traits in his son (see the “Steam-Powered Inspiration” subhead below for more background on Carsten’s early influences).

Despite his intellectual curiosity, Carsten was not fully at ease in formal academic settings. However, he did attend Sacramento State University, where he earned a BSEE degree in 1966. After graduation, Carsten went to work for Boeing, where he spent the first year and a half in the 737 flight test program designing instrumentation. But as business boom led to bust, Carsten found himself among the thousands of engineers laid off from Boeing in 1969.

Though losing his first job was unpleasant, it eventually led him to opportunities in power electronics. After leaving Boeing, Carsten found work in Vancouver, British Columbia, Canada, at Glenayre Electronics. This presented a great opportunity for him because, as Carsten describes it, his new employer was “a small struggling-to-stay-afloat company that would take on almost any project to help meet the payroll.” That environment gave him a chance to work on a wide variety of projects, such as a Doppler sonar “fish finder” and an inductively coupled transponder analogous to modern RFID tags. In one project (circa 1973), Carsten was initially using CMOS logic, but was forced by management to design it out in favor of LS TTL to reduce cost. Other engineers subsequently designed CMOS back in as its cost dropped and its lower power consumption proved necessary.

When the change back to CMOS occurred, Carsten was asked disparagingly, “Why didn’t you use CMOS in the first place?” This experience taught Carsten to trust his instincts when it came to anticipating trends in technology, and after a few similar experiences, he learned to say, “Let me do it my way or fire me.” Unfortunately, taking that stand put him at odds with management, and thereafter, he says, “I was not considered to be a good team player.”

In spite of such difficulties, Glenayre Electronics gave Carsten his entry into power-supply design. His first power-supply project was bequeathed to Carsten by a departing engineer who was overly optimistic in describing his power-supply design as “90% finished” when he passed it to Carsten.

A 750-W, 120-V to 24-V dc-dc converter, this design consisted of an unregulated silicon-controlled rectifier (SCR)-powered McMurray-Bedford dc-dc converter followed by a switching regulator built using silicon bipolar junction transistors (BJTs). Carsten spent several months solving design problems while the customer screamed for delivery. “This bad experience with SCRs caused me to shun them to this day,” says Carsten.

At Glenayre, Carsten also designed high-power battery charger/battery eliminators using a transformer rectifier with 480-Vac, 3-phase input followed by a transistor-switching regulator. These switchmode-regulated chargers (circa 1972) put out 120 Vdc nominal at 50 A and 75 A, and 24 Vdc nominal at 200 A. Designing these chargers taught Carsten a few lessons that stuck with him. After incorporating cooling fans in some units, he discovered they tended to suck all the dirt out of the environment and deposit it on the circuitry. That experience sold him on the idea of natural convection cooling, which forced Carsten to become fanatical about efficiency.

But even with highly efficient, convection-cooled units, there were still occasional failures in the field. When units failed, Carsten learned that the person expected to maintain and repair his sophisticated equipment was typically an electrician with a multimeter and a leather tool pouch. “That revelation led me to develop hot-swap power modules years later,” says Carsten.

Want to use this article? Click here for options!
© 2007 Penton Media, Inc.