Billion Watt Load Bank Build

WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#41
Joined
Aug 10, 2015
Messages
11,643
Location
Minnie-Soda
Tagline
Screw it
#41
wattsabundant said:
Try slowly opening a knife switch with 100 VDC and watch the fire ball. With care you can sustain a very nice arc, right up until it melts down into a puddle.

My bleeder resistor is hard wired to test probes. When you make the connection to the charged cap, jam it on there and leave it for a few seconds. If you pussy foot around with it you can draw a nice arc, especially if there are bus bars in close proximity to each other. The ringing in your ears will help you remember to do it the right way the next time.
Click to expand...
I have big spring loaded clips and they are soldered to some speaker wire and 2 big resistors. Don't remember what value they are but I'll find them and report back. I got shocked.... ONCE.... I was troubleshooting a radar system and I haven't done it since then, 1983. The High Voltage Power Supply got me. The DC blew a hole in my thumb. If you get a Safety Violation during training you fail the module and have to redo it. So, I put the unit in standby, calmly walked out to the smoke pit and then I screamed. Smoked a dozen heaters and went to the enlisted club for a dozen beers. When firing up an amp for the first time, I still use earphones. I hate things that go KaBoom when you when you aint ready for it.
 
WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#42
Joined
Aug 10, 2015
Messages
11,643
Location
Minnie-Soda
Tagline
Screw it
#42
[QUOTE="WOPL Sniffer, post: 359951, member: 737"]I have big spring loaded clips and they are soldered to some speaker wire and 2 big resistors. Don't remember what value they are but I'll find them and report back. I got shocked.... ONCE.... I was troubleshooting a radar system and I haven't done it since then, 1983. The High Voltage Power Supply got me. The DC blew a hole in my thumb. If you get a Safety Violation during training you fail the module and have to redo it. So, I put the unit in standby, calmly walked out to the smoke pit and then I screamed. Smoked a dozen heaters and went to the enlisted club for a dozen beers. When firing up an amp for the first time, I still use earphones. I hate things that go KaBoom when you when you aint ready for it.[/QUOTE]


Shit, I do believe thats Ghetto Cobbling. Damn, next thing ya know, I'll be using buckets of Kentucky Jelly to cool my water heater element or move my bench into the bathroom and just hang it in the toilet. When the bowl is getting hot, I'll just flush a couple times to cool er down.
 
WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#43
Joined
Aug 10, 2015
Messages
11,643
Location
Minnie-Soda
Tagline
Screw it
#43
Gepetto said:
Pretty much any old switch will do Perry...just rate it for the current involved. If you are discharging the 100V caps on a 700 with a 470 ohm resistor, you will need a switch rated for minimum of 1/2A.
Click to expand...
Joe, I've been using the cobbled bleed wire I made years ago, never sparks when using, and it has 2 series resistors which are 5 ohm 50 watt each.... Is that not sufficient? Maybe with the switch in line, I need to go to a 470 Ohm instead of my 10 ohms 100 Watts?? I was going to make my own cement resistor since I have 2 60 lb bags of Portland Cement sitting here. I had 2 bags leftover from when I made the wife a pair of shoes.

Bleed cable for bulk caps.jpg Bleed cable for bulk caps.jpg
 
Gepetto

Gepetto

Administrator
Staff member
#44
Joined
May 15, 2011
Messages
14,138
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#44
wattsabundant said:
Try slowly opening a knife switch with 100 VDC and watch the fire ball. With care you can sustain a very nice arc, right up until it melts down into a puddle.

My bleeder resistor is hard wired to test probes. When you make the connection to the charged cap, jam it on there and leave it for a few seconds. If you pussy foot around with it you can draw a nice arc, especially if there are bus bars in close proximity to each other. The ringing in your ears will help you remember to do it the right way the next time.
Click to expand...
Hi Don
To draw the type of arc you are mentioning, there will need to be a voltage source, a current flowing from that voltage source through the switch you mention into a load along with some relatively significant unquenched inductance in line with that circuit. That is not the case of a capacitor dump switch unless, as I have mentioned, you have very long lengths of wire connecting the capacitors to the dump switch and resistors. Those long wire lengths are responsible for making that inductor in a case like that. And those will have to be very long lengths of wire to do anything like you note. Interrupting a DC current that is flowing through and inductor will produce that very high flyback voltage that can cause the arcing you mention. Lacking an inductor in series, it is just a switch interrupting a current to a resistive load.
 
WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#45
Joined
Aug 10, 2015
Messages
11,643
Location
Minnie-Soda
Tagline
Screw it
#45
Got some more progress done with "The Porcupine" Load Bank. I got to sit on my ass and started laying out how I want the face plate to look. Came up with a plan to get it up and operating soon. I have to order a stencil, or, for a few more bucks I can get a nicer Acrylic sign for the front of it. As for the Porcupine, I'll post a better pic but it is big/heavy/and full of sharp pointy shit and you'll see why I call it that.



View attachment Image_20250330_0001.jpg
 
You must log in or register to reply here.
Top