310V will get your heart racing!

[maynardg]

Wow. For the first time in 10 years I ran afoul of one of my tube amp power supplies. And the amp was off. Despite a drain resistor. Thankfully, just the jolt from not fully drained supply caps. Whoa - lucky me. I'll not be doing that again.

Let's be careful out there!!!

[curt_c]

Re: 310V will get your heart racing!

You adrenaline junky! :D

Nothing straightens you up faster than being the ground path for B+.
I have found from personal experience that this often can result in the 'subject' involuntarily recalling how to levitate. Sadly, the knowledge of levitation seems to be transient in nature, and disappears with the charge.

C

[Paul Carmody]

Re: 310V will get your heart racing!

You adrenaline junky! :D

Nothing straightens you up faster than being the ground path for B+.
I have found from personal experience that this often can result in the 'subject' involuntarily recalling how to levitate. Sadly, the knowledge of levitation seems to be transient in nature, and disappears with the charge.

C

So all I have to do is shoot high voltage through myself, and I'll recall my subconscious ability to levitate?

If I listen to infrasonic frequencies, will I recall telekinesis? Because that's the superpower I really want! ;)

[Æ]

Re: 310V will get your heart racing!

Bah! That was nothing.
How about accidentally discharging the power supply capacitor (1,500 volts) inside a microwave oven? Burned a hole in my finger.
Or how about touching the flyback/high voltage (12,000 volts?) inside a TV?
Fortunately for me it was only a black and white TV!

Wow. For the first time in 10 years I ran afoul of one of my tube amp power supplies. And the amp was off. Despite a drain resistor. Thankfully, just the jolt from not fully drained supply caps. Whoa - lucky me. I'll not be doing that again.

Let's be careful out there!!!

[johnnyrichards]

Re: 310V will get your heart racing!

I grabbed hold of 480 three phase while standing in some water. Long story short, it was the last time I trusted someone else to perform a lockout. It threw me back and gave me some nasty burns on my fingers.

It feels like the biggest cup of coffee in the world, consumed at a very rapid rate. Very strange feeling. Doctor says I was lucky not to go into fibrillation and that the water, while facilitating the current path, probably saved me. I might not have been thrown like that if I had offered more resistance to the juice.

[Æ]

Re: 310V will get your heart racing!

Wow, you were fortunate enough to still be alive!

I grabbed hold of 480 three phase while standing in some water. Long story short, it was the last time I trusted someone else to perform a lockout. It threw me back and gave me some nasty burns on my fingers.

It feels like the biggest cup of coffee in the world, consumed at a very rapid rate. Very strange feeling. Doctor says I was lucky not to go into fibrillation and that the water, while facilitating the current path, probably saved me. I might not have been thrown like that if I had offered more resistance to the juice.

[ctbowman]

Re: 310V will get your heart racing!

Bah! That was nothing.
How about accidentally discharging the power supply capacitor (1,500 volts) inside a microwave oven? Burned a hole on my finger.
Or how about touching the flyback/high voltage (12,000 volts?) inside a TV?
Fortunately for me it was only a black and white TV!

12kv is a lot. I Saw a guy get 18kv once... burned a hole about a quarter inch deep and all the way across his hand. The volts aren't bad... it's the amps that'll kill ya.

[WWWJD]

Re: 310V will get your heart racing!

Oh yea... I've got a few accidental discharges in my resume.. anywhere from 110VAC to 650VDC. Fun stuff. Screwdriver slip put my pinky finger on a 650VDC buss bar in a RF generator once... had to check my head to make sure I didn't split it open on the bench, and then check my crotch to make sure I hadn't evacuated myself.

[Paul Carmody]

Re: 310V will get your heart racing!

Or how about touching the flyback/high voltage (12,000 volts?) inside a TV?
Fortunately for me it was only a black and white TV!

I'm surprised more people haven't walked down that same stupid path. (I have) Back in high school or college, I was noodling with a TV, taking it apart after having watched it. I lift up this suction-cup looking thingy on the top, thinking, "I wonder what's under here?" It actually didn't give me much of a physical mark (my finger just looked like I'd burned it on a hot pan or something), but that was by far the scariest live voltage I've ever touched.

[jonpike]

Re: 310V will get your heart racing!

Hehehe... been there, been zapped by that!!

Actually many different things over the years, 120vac, various tube B+ supplies in old TV's.. slight bite from a 12kv neon sign transformer, that was close... And, a TV flyback oscillator that would do 20kv or so, but it's high frequency AC, more RF burn than major shock. Sure turns clear lightbulbs into nice Plasma globes though..

The real fun one is about 350-400KV from a 4' high Tesla Coil... now that looks like it should kill you, but it's pretty safe... very high voltage, very low current, (despite still having a power level that will set things on fire in your hand) and about 200khz, so what little current stays on the outside of your body. Much safer than the 15KVAC 60Hz "low" voltage on the primary, which is rather likely to kill you if you got across it.

All fun aside, remember and practice keeping one hand in your pocket (or clear of anything else) when poking around on hot HV circuits... to keep current from passing across your chest if you do get bit. And, discharge those power supply caps, (or check them with a meter) even if they "should" be drained. There are better and worse ways to be surprised!!

[Hackomatic]

Re: 310V will get your heart racing!

You adrenaline junky! :D

Nothing straightens you up faster than being the ground path for B+.
I have found from personal experience that this often can result in the 'subject' involuntarily recalling how to levitate.
C

I've experienced the levitation syndrome. But more often, I found an uncontrolled blurting of rarely used vocabulary words. :eek:

I remember back to high school days in electronics class at the vo-tech school charging 450v electrolytics and tossing them to an unsuspecting victim and yelling "CATCH!" :D

[djg]

Re: 310V will get your heart racing!

Even 24 volts discharged from an aircraft battery across your metal wristwatch band to ground will get your attention. Blew the second hand off the old Seiko. Interesting burn pattern on the wrist.

[Hal H]

Re: 310V will get your heart racing!

I'm surprised more people haven't walked down that same stupid path. (I have) Back in high school or college, I was noodling with a TV, taking it apart after having watched it. I lift up this suction-cup looking thingy on the top, thinking, "I wonder what's under here?" It actually didn't give me much of a physical mark (my finger just looked like I'd burned it on a hot pan or something), but that was by far the scariest live voltage I've ever touched.

Yup, me too! Under the suction cup looking thingy is 25kV on a color tube.
I've been bitten more times than I care to think about. There are some pretty nasty monsters hidden inside radar equipment too.

I do a demonstration with my students showing what can happen with charged low voltage caps. That spark makes my point.

[AJ]

Re: 310V will get your heart racing!

I remember back to high school days in electronics class at the vo-tech school charging 450v electrolytics and tossing them to an unsuspecting victim and yelling "CATCH!" :D

Ahh... Yes, good times. It's always a good sign when the vice principal, The principal and both secretary's are on a first name basis with you because of various "accidents" in the shop...

[envisionelec]

Re: 310V will get your heart racing!

I recently ventured into the design of offline power supply conversions with PFC front ends. It's basically a voltage regulator for your switching stage by drawing a purely (or nearly so) sinusoidal current waveform keeping the Power Factor near unity.
You've all seen the "universal input 85-250V" type power supplies - well they do that by converting everything to 350VDC before conversion. Of course, there are varying degrees of capacitive banks right after the PFC and they hold a charge that will throw you across the room. Just one more "whatchout!" [sic] to throw in the mix.

It's the current, stupid. :D