Microwave Power

Discussion in 'General Technical Questions and Answers' started by WA9SVD, Jan 9, 2018.

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  1. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I was an FAE with Semtech at the time.

    Diodes Inc. isn't a manufacturer, they're a "brand" and have stuff labeled for them by many companies, mostly in Taiwan and then China, but some come from Microsemi.

    I first got involved with Magic Chef, I think; they were making microwave ovens for a few different brand names -- memory is a bit hazy as this was back in about 1977-78. They were experiencing a high HV rectifier failure rate, to the point that they had a lot of warranty returns in addition to on-line test failures in the factory. They, and some others, were "fixing" this by upping the number of stacked junctions in the rectifier until they were using 25-30kV rectifiers! Which still failed.

    We developed a high avalanche energy stacked junction device rated 7kV PIV but it could handle a lot of kickback energy, hundreds of mJ. It worked and that was the end of the problem. We used exactly the same technology to make HV rectifiers for X-ray machines, but those used many more diodes and were rated 200kV (but still high energy designs) which solved a lot of problems for G.E., Picker, Siemens and others at about that same time. The 200kV units hardly needed any insulation since they're always operated in a dielectric oil bath, so they were actually pretty small for their rating.
  2. K8ERV

    K8ERV Ham Member QRZ Page

    Paul Heyman?

    TOM K8ERV Montrose Colo
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I knew Paul. I think he's SK by now, he was quite a bit older than me. Nice guy!

    Semtech had hams as regional managers in many places, though. K2ZGB was eastern region, WB6FDR (now W6FDR) was western region, and after Marty K2ZGB retired, I took over the eastern region. Our Chief Engineer was also a ham, as was the co-founder C.T.O.
  4. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I might be wrong, but I think it was actually Paul Heimann. Fuzzy recollection, I haven't seen him since about 1980 or something. He was Central Region manager.
  5. K8ERV

    K8ERV Ham Member QRZ Page

    I show both spellings in my Tappan log, not sure which is right

    TOM K8ERV Montrose Colo
  6. WA9SVD

    WA9SVD Ham Member QRZ Page

    They may have sold it, but I'm SURE they didn't manufacture it themselves! I believe it was produced by Sharp for Monkey Wards, as Sharp was the first with a built-in rotating turntable. (Or so I've been told.) It's still the old, heavy type, not a lightweight with a switching power supply!
  7. N8EKT

    N8EKT Ham Member QRZ Page

    My sister still has a working Amana radar range from the mid 70s and it still has the original magnetron.

    By the mid 80s, the Korean microwaves were king and Samsung was the most common
  8. N8EKT

    N8EKT Ham Member QRZ Page

  9. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I think Raytheon was responsible for the original "Radar Range," although that's also a hazy memory.

    Litton made magnetrons and also made microwave ovens for a while.

    Today, isn't it all Chinese? They seem to have perfected making very cheap magnetrons which are only about $20 each or something.

    I've had many, many microwave ovens over the decades and I don't think a magnetron ever failed in any of them: It was always the power supply, or something mechanical like the door latch.
  10. K8ERV

    K8ERV Ham Member QRZ Page

    Misc: Yes, Sharp had the first turntable, think they called it a Carousel. Did not heat more evenly than the previous
    "stirrer" in the ceiling, but became popular cause it showed something was happening.

    Raytheon was a major developer/supplier of the early Radar equipment in the latter days of the Great War. After that they made radars for boats. Don't know about airplanes. But they wanted to use their expertise and hardware to get into the domestic (home) market, something they were not very good at. They licensed Tappan and together produced the "RadarRange, a large, heavy, powerful, and expensive ($1,300) built-in wall oven. Used 220 volts. We made about
    7 per day. Dick Tappan said it was not a money-maker, but helped to build Tappan's image as being progressive.

    This oven was introduced at a show in NYC in the summer of 1955. I joined Tappan in Jan 1957 to continue the development. Later Raytheon acquired Amana,, primarily a refrigerator company. They developed the first 115-volt
    countertop oven and the rest is history.

    TOM K8ERV Montrose Colo
    tpn R4 intro (Large).jpg
    WB2UAQ likes this.

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