[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: New DRSSTC first light and a question

Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Skip,

DigiKey sells nice little CTs right off the shelf:

http://drsstc.com/~terrell/pictures/CTshield.JPG

DK# 237-1097-ND $6.67
120A 10kHz to 200kHz
Saturation, current, frequency response... are all ready "all figured out" for you ;-)

These will easily do 200 amps peak. If you need more current, perhaps you can tap into the MMC cap for a lower current leg (the current thought say 1/4 of the MMC strings). Dan and some others i think used secondary feedback where the currents are far less.

I use a bit of grounded brass tubing for a RFI shield too.

Put the burden resistors way back at the electronics to reject noise:

http://drsstc.com/~terrell/pictures/CTwiringBad.gif

http://drsstc.com/~terrell/pictures/CTwiringGood.gif

http://drsstc.com/~terrell/schematics/CurrentMeasurement.gif

http://drsstc.com/~terrell/schematics/ProtectionCard-1.2.pdf

Be super sure to see this note...

http://drsstc.com/~terrell/notes/TerrysDRSSTCnoiseFIXES.pdf

Happy to see another joining the DRSSTC club :-)

Cheers,

        Terry




At 04:46 PM 9/17/2005, you wrote:
Hi all
Here is a quick spec on the new DRSSTC
I used Dan's full H bridge driver but with primary feedback driving four IRG4PC40W IGBTs
Secondary: Dia: 4.5", 1000 turns #26
Primary: Dia: 6.5", 5 turns #10
Cap: .04
Top load: 2" x 8" toroid
Resonant Freq: 285 khz
Power: DC using a full wave bridge on 115vac input. I expect to go to 240vac input
At 40vac input the output spark is over 6"

To obtain the feedback I run one of the primary leads through a toroid core. The feedback winding is one turn on the core.

Problem: The toroid core get VERY hot running at 40vac input. Too hot to touch. Is there a better way to develop the feedback????

I would appreciate any suggestions.
Skip