Dear All,

Here is the schematic for the circuit under consideration. Note this is a simplified approach and is not as advanced as the original Gunderson circuit, but it is a lot cheaper.

Spokane1

Attached Images

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	IMG_0227 - 800.JPG (149.3 KB, 36 views)
	IMG_0223 - 800.JPG (115.8 KB, 34 views)
	Junk Box Mockup 8-23-2016 Capture.JPG (78.7 KB, 65 views)

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Just found out about this project today... and read all I could... very interesting.

I've been wondering why nobody has suggested using IGBT's, instead of "extreme" SiC MOSFET's. IGBT's are far more "at home" with high voltages, and much cheaper.

The switching "ON" state loss isn't measured in milliOhms as in MOSFETs, but rather in Volts like bipolar transistors (which it is)... but when you consider the SiC MOSFET has 25mOhms RDS(on), if you had 90A pulses going through it, you have 2.25V VDS(on). That's a typical VCE(on) range for high power IGBT's... regardless of the current.

If the H-bridge switching pulses are low current, then the MOSFET can have less power loss... but IGBT's can still handle peak Voltages much easier... and at FAR lower prices, and still have extremely good (fast) switching speeds.

Their Gate drive requirements are very similar to normal MOSFETs... +5 ~ +15V range (nominal).

The NGTB25N120FL3WG (US$4.66 ea.) is 1200V, 100A (@25C), 1.70V VCEsat at 25A @ 25C, rise time 21nsec, turn-on delay 15nsec

I know the first working unit was just that... throw sturdy parts it for safety's sake... but for full-scale replications... it may be a good alternative.

(just sharing some thoughts...)

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Dear 3758,

I'm sure that whoever replicates this device will use the solid state switches they have faith in and those that they can afford. I'm sure the fundamental physics of this process doesn't care how the fast switching speeds are acheived. Dr. Tesla and E.V. Gray employed quenched spark gaps. Paul Babbcock uses a series combination of SCR's, IGBJT's, and a sterring diode.

Until we understand what is going on we just don't know the required rise and fall times of the switching elements or the magnitude of the Vdds ratings that are needed.

Go ahead and use what you have on hand. I'm sure that for every replication built a differet type of switch will be used.

Spokane1

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Dear All,

I have been exploring the performance of the simplified single switch approach in building a Graham Gunderson system.

I have found that even though the primary voltage looks the same under unloaded conditions it becomes distorted when load is applied to the secondary. At maximum loading the second positive swing of the input voltage dissapears. That can't be good for the non-clasical process we are hoping to duplicate.

I am now building a full H-Bridge and am adding the logic necessary to time the second phase.

Spokane1

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...and much slower.

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Graham Gunderson Energy conference High COP demonstration

and here

Graham Gunderson's Energy conference presentation Most impressive and mysterious

respectfully

Chet K

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Dear All:


Here is a simple variation to the logic circuit to generate the Phase B signal for the H-Bridge.

Spokane1

Attached Images

	IMG_0632-800.jpg (144.3 KB, 14 views)
	H-Bridge Logic Variation 9-18-2016.JPG (61.2 KB, 25 views)
	IMG_0633-800.jpg (223.6 KB, 15 views)

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also being discussed here

Graham Gunderson's Energy conference presentation Most impressive and mysterious

Magnetic Compression Study" by Cyril Smith

respectfully

Chet K

Attached Files

The Gunderson Smith Effect.pdf (120.5 KB, 38 views)

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Thanks to a new friend Jim D for sharing today .

https://www.youtube.com/watch?v=aqxFC70wyM0
https://www.youtube.com/watch?v=WvSBVu3c_BE

more info to follow
much gratitude to Graham for Open sourcing

ChetKremens@Gmail.com

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liked videos, nice.

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