DRSSTC trips GFCI outlet

[boom198]

This is a first time post.
I had built a DRSSTC earlier in the year and it was a successful build, however due to remodeling my basement I no longer have any non-GFCI wiring in the house and the coil trips the outlet after .50 seconds of use. In other cases when operating an outlet connected to the relay box there were not operational issues.


I'm wondering if I don't have the circuit properly grounded? I'm guessing some sort of voltage or current spike trips the GFCI

before making the final build, the low voltage and high voltage circuits were separate and were able to function without tripping the GFCI (now they're powered with the same chord)

Any experience with this problem and guidance is much appreciated. I do own a scope.

[davekni]

Any experience with this problem and guidance is much appreciated. I do own a scope.

I've personally never tried running a Tesla coil on GFCI-protected circuit.  Hopefully you will get other responses with actual experience.
My suggestion is to change the secondary bottom connection.  Wire it to safety ground rather than to the two 100nF caps.  Also consider adding a counterpoise connected to the safety ground and secondary ground connection.  This can be a sheet of aluminum foil or aluminum screen or any such conductive layer under your coil, far enough below primary and secondary windings to avoid blocking magnetic field.  At least secondary coil radius spacing.  Coil diameter or more below is better.  The larger the better.  I place aluminum sheets/foil/screen along the floor under my DRSSTC.

[Mads Barnkob]

GFCI or RCDs (Residual Current Detection) as its named know, in Europe at least, only acts on leakage current back into mains supply ground. As Dave says, this indicates that your RF ground is not good or you have part of your circuit that is bad.

I normally start by disconnecting one ground lead at a time until I find the culprit and then investigate on that one part. You should be able to run a coil according to this schematic of Tesla Coil grounding in this part of the DRSSTC design guide: https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/grounding-circuit-protection-and-emi/

I am able to run my coils on 30mA GFCI/RCDs.

Being a base-fed resonator, I must admit that I do not know enough about its grounding paths, as its no longer isolated from the bridge output.

[boom198]

i feel silly throwing this out there, but the "safety" ground from the power chord is taped off to the side. Because of way i got all my components i might have to disassemble to get the safety connected to the secondary.
there is a small chance I could work some magic and connect them up but Im short on time at the moment.
does having the secondary connected to the mains "safety" ground have any negative effect on the driver circuit?
As a hobbyist ive really only had the desire to build HF transformers and sstcs and grounding has always been some what confusing (even though its supposed to be important)

Thank you for the replies

I do have some video of the coil in operation, as well as some crude shots of the wiring.

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[klugesmith]

GFCI devices directly sense the net current in (Hot,neutral) pair, using a current transformer toroid that goes around both conductors.

They might have some nuisance sensitivity to RF power conducted from equipment to the wall wiring.
Are you sure the wall circuit doesn't also have Arc Fault protection feature?
Can you put a commercial or home-made line filter between your TC power unit and its wall plug?

For industrial EMC testing (TUV standards etc.) of conducted RF power, we use a standard box called a LISN
(line impedance stabilization network).    Includes 50 microhenry inductor in series with each phase,
to isolate the system under test from poorly controlled RF impedance in the building's power network.
I once made three 50 uH 50 amp air core inductors, and they are not small.

[Mads Barnkob]

there is a small chance I could work some magic and connect them up but Im short on time at the moment.
does having the secondary connected to the mains "safety" ground have any negative effect on the driver circuit?

I have had arcing from mains ground in a power bar, to phase and neutral. It did not damage any electronics or drivers (I used EMI filters on the inputs to these) but it did burn my power bar

[boom198]

Can you put a commercial or home-made line filter between your TC power unit and its wall plug?

would that resolve any signals that might be causing the GFCI trip? I think I could try that

[Mads Barnkob]

Can you put a commercial or home-made line filter between your TC power unit and its wall plug?

would that resolve any signals that might be causing the GFCI trip? I think I could try that

Yes, EMI filters are widely used in front of variable frequency drives in the industry. They are made to filter noise both ways, so you get less noise back to mains and your electronics gets less noise from mains supply.

Just found this on google, has a few good tips on how to mount it with short wires, position etc. https://www.astrodynetdi.com/blog/emi-filter-installation-best-practices

[boom198]

Thanks for the feedback everyone! I was able to get the coil functioning by using an EM filter. No more GFCI problems and the coil functions just as it did before.

Thanks again