High Voltage Forum

Tesla coils => Spark gap Tesla coils => Topic started by: thedoc298 on October 10, 2019, 06:54:46 PM

Title: safty gap resisitor
Post by: thedoc298 on October 10, 2019, 06:54:46 PM
I was reading back a few months and someone mentioned,"don't forget your safty gap resisitor, few ohms would be good". This would be so your cap is not doing a direct short which make sence. I am going to use a 100watt 4 ohm. The question is are you guys out their doing this and what value are you using. Thanks
Title: Re: safty gap resisitor
Post by: MRMILSTAR on October 10, 2019, 08:38:04 PM
The purpose of the safety gap is to protect the transformer, not the capacitor. If the capacitor is suitably rated in voltage (at least 2.5x) that should be protection enough for it.

Since the safety gap is there to protect the transformer, the safety gap should be connected in parallel with the normal spark gap. Because of this there is no need for a resistor because the discharge is still into the tesla primary coil which will oscillate with the capacitor as with the normal firing.

I have seen a circuit with the safety gap in series with a resistor connected across the capacitor but this makes no sense to me unless it is an attempt to protect an under-rated capacitor.

My safety gap is connected in parallel with my SRSG as with all other RSGTCs I have seen.
Title: Re: safty gap resisitor
Post by: thedoc298 on October 11, 2019, 01:09:18 AM
The purpose of the safety gap is to protect the transformer, not the capacitor. If the capacitor is suitably rated in voltage (at least 2.5x) that should be protection enough for it.

Since the safety gap is there to protect the transformer, the safety gap should be connected in parallel with the normal spark gap. Because of this there is no need for a resistor because the discharge is still into the tesla primary coil which will oscillate with the capacitor as with the normal firing.

I have seen a circuit with the safety gap in series with a resistor connected across the capacitor but this makes no sense to me unless it is an attempt to protect an under-rated capacitor.

My safety gap is connected in parallel with my SRSG as with all other RSGTCs I have seen.
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yea I just looked again and when the safty fires it is not dead shorting the cap which is what I thought. The primary is in series with it with the cap so no short.

When I looked at my papers I kept seeing the safty across the cap dead shorting when it would fire, but it was across the main spark gap. Anyway all is well and you fixed a problem that did not exist. Cant believe how my eyes were playing tricks. The whole problem is i drew the cap and the safty gap the same.

She is about ready to fire, just got to put the terry filter stuff in, kind of forgot that stuff, so a little backtracking. Thanks again I feel better now.