30% power increase

[MRMILSTAR]

I recently increased the power of my big SGTC by about 30%, from 4.8 KVA to 6.5 KVA. This was very simple to do on my equipment. All I had to do was increase the air gap on my ballast very slightly. JAVATC predicted a 9-foot maximum streamer length. A neighbor took the attached picture. If I stretch out all of the kinks, the streamer length does indeed measure to about 9 feet. For reference the coil is 75" tall.

This is the maximum power that I can safely use with my current components. My weak link is my variac which is the largest General Radio variac available. It is rated for 240 volts at 25 amps continuous and up to 32 amps with cooling intervals. My current power level draws 27 amps, with PFC, through the variac. This is the maximum that I am comfortable with unless I want to make major modifications (2 ganged variacs and more capacitance).

[Mads Barnkob]

I was never so bold to "stretch" out the spark for spark length measurements 

Most variacs are rated for 200-300% operation for very short periods, it will however hum violently, just if you wanted to push things a bit

[MRMILSTAR]

The GR variacs also have an internal fuse which I believe is rated for 32 amps, so that is another limitation. I could just bypass the fuse since my control cabinet has a 40 amp breaker. However, going higher than 27 amps would be largely pointless without increasing the size of my primary circuit capacitance. With my 45 nF capacitance, JAVATC says that my capacitors are 95% charged at the start of each bang (240 BPS) with 27 amps. I could increase the capacitance to 60 nF since I do have additional Maxwell energy discharge capacitors. I might do that some day but for now, 9-foot streamers satisfy me.

My ultimate limit though are the 40 amp breakers in my distribution panel.