Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  • Users: Skogsgurra
  • Content: Threads
  • Order by date
  1. Skogsgurra

    Induction heating. Low tq thyristors

    Self-commutated H bridge. Running at 400-600 Hz with DC up to 2 kV and output current up to 1 kA. The original design uses three thyristors in each "leg" of the H. The reason is that fast thyristors were not available at 2 kV at the time of its conception and birth. It seems to be time to...
  2. Skogsgurra

    Electrolytic capacitors - low voltage/reduced capacitance

    I am running a column in the Swedish paper Elektronik i Norden http://www.elinor.se/hur-gammal-kan-elektronik-bli.html/ where different topics are covered. A Little like Bob Pease did in Electronic Design. A question about elctrolytic capcitors and how capacitance changes with voltage was...
  3. Skogsgurra

    18 MW synchronous motor - thyristor triggering problems

    The ubiquitous rotating exciter with thyristors shorting the excitation winding to turn it into a starting winding has been used for decades. And mostly done its thing as expected. The trigger units, we have had problems with Siemens and ABB ones, start to show problems. They are sometimes...
  4. Skogsgurra

    HELP!!!

    I never tried that subject line before. But I did add three exclamation marks for clarity and better understanding. Didn't I? The problem: Anyone seen a UUUUUUUUU task card for Dranetz? Or, more realistic: How to proceed? The manual doesn't say. I haven't used this one for more than fifteen...
  5. Skogsgurra

    Phase angle controlled heating results in extreme electric bills

    About ten years ago, customers all over Sweden (and probably also in many other countries) noticed that their electric bills jumped sky-high after "intelligent meters" had been installed. I did tests with three different brands of meters plus an old analog watt-meter (Norma class .5) and also...
  6. Skogsgurra

    Residual charge in 4 kV motor - any limits?

    The phone rang just before midnight. That is usually a bad omen - someone needing immediate help with some critical equipment. I am all for THAT kind of problems. But this was different. One of the electrical guys was replacing a 4 kV motor, probably around a few MW size. The motor was...
  7. Skogsgurra

    Ternary - anyone?

    I don't need the basics of ternary. But I need a reference to a text where it is shown how to add/subtract +1/0/-1, +3/0/-3 etcetera (in Excel would be nice) so I don't have to hand-calculate a zillion combinations. I started to make mistakes at +81/0/-81. Google says a lot about ternary - some...
  8. Skogsgurra

    Simple wireless 1/0 transmitter/receiver

    Need a simple device that can feel a contact closure and transmit the 1/0 state over around 100 m distance. More is better. It shall be used for temporary check out of measurements and there is a demand for low latency, or at least consistent latency. Either less than around 500 us latency or...
  9. Skogsgurra

    IMF wants to know if you really died...

    I receive so many letters from guys that want me involved in sending them money. Or something. But Mr. Braunwalder Garland gets the prize: He asked me "Did you" (die, that is). So, I answered him like this: Thanks a lot for your kind letter, Mr. Braunwalder! Yes, I died last year, not last...
  10. Skogsgurra

    A humble and modest question

    Suddenly this morning, my keyboard or PC or whatever refused putting the same thing on screen as I pressed on the keyboard. A few examples. Paranthesis became * and (. AT in mail addresses became nothing, Exclamation mark works ! and period, too. Our diacritic letters, aa ae and oe, became {@...
  11. Skogsgurra

    Circle closed - Silicon

    There are sometimes minutes of pure joy and beauty. Not so often in engineering - but they do occur. Like yesterday. We live in a very mineral rich part of the World, the Bergslagen in Sweden. Not far from us, to the west, is the Långban mine. One of the mineral-richest mines in the World. If...
  12. Skogsgurra

    Escalator accident in Stockholm subway

    An escalator went amok a few days ago. Started moving backwards with lots of people on it. Speed way above nrmal. Brakes didn't work. Coupling bad, was my first thought. Today, there is a picture in the papers showing the coupling. The press spokesman (yes, a male)said that the accident was...
  13. Skogsgurra

    Capstone units. First generation.

    Hello all! I have been absent for a few weeks. Not dead, not ill. Just a lot of work and no easy internet access. But, just you wait! Back again - with a load of questions. The first one is this: Do Capstone gas turbine generators aged somewhere between 30 and 40 years have CSI inverters to...
  14. Skogsgurra

    PIC24HJ12GP202 DIP!!! ???

    Looking for a bunch of these processors. DIP difficult to find. Any tips? Gunnar Englund www.gke.org -------------------------------------- Half full - Half empty? I don't mind. It's what in it that counts.
  15. Skogsgurra

    Powerful 7-8 kHz ringing. CSI inverters and high capacitance cables

    I found this waveform (measured L1-PE) in a 400 V grid: Fifteen years earlier, I found this: The ringing could also be seen on the MV side of the transformers. The utility guys said there was nothing to see. Their Fluke and Dranetz analyzer didn't show anything. That is understandable as...
  16. Skogsgurra

    Fluke 438-II

    Anyone tested this? Thoughts? Gunnar Englund www.gke.org -------------------------------------- Half full - Half empty? I don't mind. It's what in it that counts.
  17. Skogsgurra

    12 MW refiner motor - Excitation issues

    I did my first measurements on machines like these 15-20 years ago. The exciter shorts out the excitation winding during start (high induced voltage due to high slip makes the control unit gate the thyristors on) and when near synchronous speed, the induced voltage is reduced so the thyristors...
  18. Skogsgurra

    Why do large companies punish relatively innocent EE:s?

    A dominating business magazine (electroics) sent me a link to a book so I could brush up on measurement techniques. The book is sponsored by another company, known for modular instrumentation with a “no programming” programming language – which means that it is graphical instead of text based. I...
  19. Skogsgurra

    Tiny test pins. Stolen from Missus...

    I got soo tired when trying to connect to a little breadboard weighing around ten grammes and using test clips/cables with 1 mm2 Cu cables. The tiny EZE-hooks dont't work very well if you need to attach to female connectors and they can't be used to probe tiny IC pads. So I took a tour around...
  20. Skogsgurra

    What display technology and make?

    Needs: 4 rows 16 or 20 characters. No graphics. Light-emitting or reflective with background light. Light on/off/intensity selectable. Colour OK but not necessary. Mature technology. Constraints: Shall work from -20C to around +50C. Lowest possible (<10 mA) power consumption. Life better than...

Part and Inventory Search

Back
Top