Do not underestimate the power of the brick. V2

Kizmo, Sun Sept 23 2012, 08:07PM

Just little bit something i wanted to share with you guys.

Inspired to by this thread:


My victim was Semikron SKM150GB128D which i got from German ebay for 20 euros.

Datasheet:


I wanted to see what kind of power levels and general abuse brick like that take. So far it has been very interesting.

Coil spec:

160x500mm secondary, about 1550 turns
100x490mm topload
flat pancake style primary, k=0.16
667nF tank capacitor
370VDC bus, 5600µF bus capacitance
Single phase 32amp feed

Secondary unloaded resonant frequency was measured to be 115kHz, primary was tuned to around 104kHz.

First test setup looked like this. Later i added some more capacitors in series and made nice sealed metal box for driver. (Whole thing was put together from scrap parts in two days, it sort of shows in some places )




First test at my student apartment, seriously limited by 10A breaker, room and noise.


2nd test later at other place where noise, room or power are not problems..


As video title said, i didnt have Over Current Detection in use. I did scope primary current and during air streamers it was around 1.5kApk and during heavy ground arcing it went way past 2kA. Coil seems to be making scariest sparks at around 300-400bps and 100-120µs on time.

Once i chose primary components i knew this thing would need serious amounts of primary current for impressive spark output. Low impedance primary (Zprim 2.22ohm), half bridge and relatively low input voltage made sure i was not wrong. (its hard to get any sparks out of that thing with less than 500Amps in primary!)

Coil ran just fine at 3-4kVA input power from wall for quite some time. Then primary cable that was leaning against bus capacitor mounting strap induction heated that steel strap to a point where cable insulation failed and it shorted primary lead to house ground. And it of course blew rectifier bridge and fuses from electrical panel.

Seems that everything else survived. Maybe next weekend we will see series-parallel bus capacitors for 3 phase power (565Vbus?) Maybe OCD will be added too..