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RE: Terry's DRSSTC - First light ;-))

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>


At 12:12 AM 3/6/2005, you wrote:
Details Terry ;-) What was the power input? Spark length? Off and on time
and all that jazz... Good to see you getting some nice results, and even
better yet, frying some Si!


David Trimmell

The coil seems to almost exactly match the MicroSim model:


For input power:
16 amps max at 120VAC.  I do not know the power factor or real power.

The BPS was varied from 50 to 300 and the pulse width from 10uS to 500uS.

Primary is 37.5nF cap with a 50uH primary coil for about 117.5kHz
Primary coil is 1/4 copper tubing. 11.75 turns with 6.5" dia inside diameter and 16.25 inch outside dia.
The peak primary voltage is about 9kV with a peak current around 250 amps. The primary current limit was set to 300 amps which it never hit.

Secondary is about 1363 turns of #28 on a 6 inch tube 20 inches long on a 1/8 inch poly carbonate tube. 73.63mH which has a resonant frequency of 119.5kHz.

Top load is 6.5 inches (center) above the top winding of the coil. 17 inches outside diameter with a 4 inch cord dia made from dryer duct.

The secondary is about 1/2 higher than the primary for a coupling of 0.165. Even though they are only about 1/2 inch apart, it never arced over. There was never any sign of racing arcs.

The IGBT temperature limit was set to 60C (about 10-15C out temp) and never tripped.

It was a little windy out, but some of the streamers were 3 feet easily. This coil is far from "optimal" for streamer length and such but is super easy to transport.

Cool Terry!!
Congratulations for a good looking and working
Do the IGBT heat up?


They don't seem to. The temperature limit was set to 60C with the air at say 15C and it did not trip. When I get the little Velleman scope I can plot the temperature. Since the switching speed is so fast and the fan directly blasts the directly mounted IGBTs they "should" run pretty cool. So not sure of the temperature, but I had no problem at all with it.

What are IGBT's?


"The Insulated (or sometimes called Isolated) Gate Bipolar Transistor combines the simple gate drive characteristics of the <http://en.wikipedia.org/wiki/MOSFET>MOSFET with the high current and low saturation voltage capability of <http://en.wikipedia.org/wiki/Bipolar_junction_transistor>bipolar transistors by combining an isolated gate <http://en.wikipedia.org/wiki/FET>FET for the control input, and a bipolar power transistor as a switch, in a single device. "

They are basically transistors that are very easy to control like a FET and they can take super high currents. IGBTs like I use have been tested to 750 amps!!

I see the server has been real busy downloading the movie ;-)) Be patient ;-))