Onetesla TS driver board for OWN coil need some help

[donnersm]

I bought a onetesla t’s replacement kit with the idea to use it’s driver board and interrupter for my OWN coil....so far so good.... I got it to arc for about 0.2 seconds after which the driver board died. The IGBT’s are blown, so is the double bridge rectifier, and the Logic Ic’s on the low power side of the board. In order to figure out what went wrong and to fix it...i want to clarify a few things:

1. The DRSSTC basicly finds it own resonance based on the primary coil and capacitor. The interrupter has no part in this.  Correct?
2. Since i use my own secondar coil, the resonance frequency is different from the onetesla original design.. 233 instead of 290Khz. This is fine as long as i adjust the resonance of my primary circuit by adjusting the number of windings ( JAVATC)??
3. The bottom of the secondare coil is connected to the circuitboard ground. ( thats the onetesla design) Maybe this is why i fried my logic Ic’s on the low power side? I could place a metal sheet on the table and connect it to the secondare coil. However, will this not create a field and sparks on the plate because the secondair coil has no +/- up down anymore...??
4. The polarity of the primary coil is not important because it swings the secondary in AC??
5. Same goes for the feedback transformer that is used?

[dexter]

1. A DRSSTC driver always works at the resonance of the primary LC. The intrerupter doesn't change it.
A problem with the onetesla driver is the lack of overcurrent protection. They get around it by having the coil tuned and by controlling the on time with their intrerupter.
If you use their driver for other coils you risk exceeding the current capabilities of the IGBT's and blow them off.
2. Yes you need to adjust the number of primary turns for a different secondary coil. JAVATC is a great tool but tuning still has to be done manually. Given the lack of overcurrent protection of the onetesla driver you risk blowing the IGBT's when tuning the coil.
3. The bottom of the secondary coil must be connected to earth. For small coils the earth pin of the outlet can be used but for bigger and powerful coils a separate earth ground must be used. Or a sheet of metal could be used but it has to be some distance away from the primary coil and i think it should be at least connected to mains earth.  As for the driver it should be shielded (placed inside a metal box) and connected to mains earth.
4. 5. The polarity of primary coil and feedback transformer have to be in phase. If your coil doesn't starts flip the feedback transformer or the primary coil polarity

[Mads Barnkob]

Hi donnersm and welcome to HVF

dexter pretty much hit all the nails right on the head, I also want to chime in on the onetesla driver should be avoided due to their low-component-count-design that for reasons of only selling more replacement kits was made without basic important protective circuits, like the OCD which is crucial for any DRSSTC.

I wrote a long DRSSTC design guide with many different topics, also about grounding: http://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/grounding-circuit-protection-and-emi/

I would advise you to start over with Steve Wards UD1.3 ( https://www.stevehv.4hv.org/new_driver.html ) or UD2.1b ( https://www.stevehv.4hv.org/leadcomp/UD2_1revB/ )

[donnersm]

Thanks guys for the feedback.
Good thing is that I was planning to build a proper driver from the start. Using the oneTesla board was more of a side track because I  was able to get it cheap and I figured the included interrupter will come in handy...considering the learning curve and the working interrupter....it was worth spending a few bucks...( $50). By now I got some good advice and help from another Dutch coiler and I already ordered some PCB's for the UD2.7c along with some components.... And mads...I will read up on that grounding ...thanks.

Anyway, anyone in my area Netherlands/Belgium/Germany in need of some UD2.7c board(pcb withoud components) send me a pm...I ordered 10 so i'll have some extra