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Guard rail?

PostPosted: Tue Aug 13, 2013 4:38 pm
by stegu
I see the point of keeping this kit simple and skip some expensive, complicated and not absolutely essential protection circuits (thermal protection, an overcurrent breaker fast enough to protect the IGBTs, and some other things that have been suggested). However, I am curious about your decision not to include a guard rail. This is almost always present on the other Tesla coil projects I have seen, and several of the oneTesla builds that have been announced here in the forum add a guard rail to the design. On one hand, a guard rail protects against primary strikes. On the other hand, it makes the assembly more complicated and also gives the spark a target for a ground strike, which is undesirable for a oneTesla.

Your manual does show a primary strike from a well protruded breakout point, so it can clearly happen. Does the circuit typically survive an event like that if it doesn't happen too often?

Re: Guard rail?

PostPosted: Tue Aug 13, 2013 9:20 pm
by Bayley
The circuit is generally fine with primary strikes - guard rails are often used to prevent strikes to the drive electronics, and the insulating chassis we use seems to do a good job of preventing that.

Re: Guard rail?

PostPosted: Wed Aug 14, 2013 3:15 am
by stegu
Good to know. Thanks! Now if I could only bring my coil into tune somehow...

Re: Guard rail?

PostPosted: Fri Aug 23, 2013 4:14 pm
by Heidi
The geometry of the setup is more important than the fact that there is insulation. Also, high voltage arcs track along surfaces (see the powerade bottle picture on the product page of the kit), so in the unlikely event of an arc that curves back towards the chassis, it will track along the surface.