High Energy Testing

[David L. Jones]

A frind of mine recently had fun testing a custom high energy PSU, too cool
not to pass on:

"This photo was taken during routine testing of my 400 joule discharge PSU.

The PSU dumps 4,500V pulses to the load, at a rate of three 400j jolts per
second.

The load resistor is a 10-ohm, 450-watt beastie which gets damn hot during
testing - more than 200degC, despite the fan.

The load resistor consists of maybe 100 turns of resistance wire.
The resistance wire is probably Monel or nichrome.
One turn is only insulated from the next by an oxide coating on the wire.
At each pulse, there's about 45 volts between adjacent turns.
Once the resistor gets hot enough, the insulation starts breaking down.
Spectacularly...

I'm glad I had the camera handy!"

http://www.alternatezone.com/images/Boomer_Testing_400joule.jpg

Dave.

 

[Franc Zabkar]

A frind of mine recently had fun testing a custom high energy PSU, too cool
not to pass on:

"This photo was taken during routine testing of my 400 joule discharge PSU.

The PSU dumps 4,500V pulses to the load, at a rate of three 400j jolts per
second.

That would be 1200J/s which is 1200W.

The load resistor is a 10-ohm, 450-watt beastie which gets damn hot during
testing - more than 200degC, despite the fan.

No wonder. It is trying to dissipate 1200W.

- Franc Zabkar

 

[Phil Allison]

"Franc Zabkar"
"David L. Jones"

That would be 1200J/s which is 1200W.


No wonder. It is trying to dissipate 1200W.

** 4500 volts into 10 ohms equates to a peak dissipation of just over 2 MW

- yep * megawatts * !!!!!

I figure there is a 40uF cap bank charged to 4500 volts somewhere just out
of the pic - the charging rate it at about 1 amp to allow 3 blasts per
second.

Wonder how many discarded microwave ovens were scavenged to make this lethal
set up ?



..... Phil

 

[David L. Jones]

"Franc Zabkar"
"David L. Jones"


** 4500 volts into 10 ohms equates to a peak dissipation of just over 2 MW

- yep * megawatts * !!!!!

I figure there is a 40uF cap bank charged to 4500 volts somewhere just out
of the pic - the charging rate it at about 1 amp to allow 3 blasts per
second.

Yep, two 23uF 5500V caps in parallel.

Wonder how many discarded microwave ovens were scavenged to make this
lethal set up ?

Two 1100W microwave oven transformers, fed by a stepdown autotransformer to
keep the voltage sane and safe (?).
This photo shows an early incarnation of the unit, with two 800W MOTs
fitted.
http://www.alternatezone.com/images/Discharge_PSU_during_assy.jpg

Dave.

 

[David L. Jones]

What will it be used for?

The Australian government doesn't want anyone to know!

Dave.

 

[Jasen Betts]

What will it be used for?

He called it a "boomer"

possibly it's a thumper:

http://www.voncorp.com/products/fault/fault.htm

 

[F Murtz]

A frind of mine recently had fun testing a custom high energy PSU, too cool
not to pass on:

"This photo was taken during routine testing of my 400 joule discharge PSU.

The PSU dumps 4,500V pulses to the load, at a rate of three 400j jolts per
second.

The load resistor is a 10-ohm, 450-watt beastie which gets damn hot during
testing - more than 200degC, despite the fan.

The load resistor consists of maybe 100 turns of resistance wire.
The resistance wire is probably Monel or nichrome.
One turn is only insulated from the next by an oxide coating on the wire.
At each pulse, there's about 45 volts between adjacent turns.
Once the resistor gets hot enough, the insulation starts breaking down.
Spectacularly...

I'm glad I had the camera handy!"

http://www.alternatezone.com/images/Boomer_Testing_400joule.jpg

Dave.

Could we test speed camera electronics with it