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Safety Practices, General and Ultra-High Voltage
Safety Practices, General and Ultra-High Voltage
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Old 4th January 2019, 06:16 AM   #371
richwalters is offline richwalters
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Quote:
Originally Posted by SY View Post
Thanks for starting this thread. If it develops well, we'll make it permanent.

Just some general comments that I've made before:

When you decide to work on high voltage circuits, spend time around experienced guys. Never work alone. For ultrahigh voltage stuff (high power supplies at 1kV and beyond), all the rules are different and you would be INSANE to the level of suicidal to tackle such a thing without the direct supervision of an experienced guy who wishes you no harm.

Too paranoid is much preferable to not paranoid enough.
Copy that....For some reason I detected luck in survival during my mixed high voltage life, now 60 yrs of it....but once in my earlier days nearly came a cropper when a field engineer asked me out to inspect /opinion on a very high 420 KVolt MW substation transformer which also handled AM signal sensoring for tap changing, and was making peculiar noises..It was huge, bigger than a shipping container. One has to take anything metallic off wedding rings etc due to induction fields, and although I was proficient in the maintenance work, at 50 yds the inconsistent lamination noise made me darned frightened and the case paint was smelling. To me it came across as a fifth sense and I said 'no way' without all being disconnected; and as we both turned around and backed off a hundred yards, it all blew up. Thanks for the visit......There are plenty of transformer exploding videos on YTube.

After that unforgetful event I've always double-eyed those massive installations with the utmost respect considering many are in residental areas!

Those of us HAMer's who have the kudos for high voltage, fine when the personal rules are observed. My rule is don't take on what one cannot handle and worse.... Don't guess. Never have both hands on an active chassis as the link via Cardiacs becomes the perfect last call.

rJ

Last edited by richwalters; 4th January 2019 at 06:19 AM. Reason: correction
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Old 5th February 2019, 08:38 PM   #372
guitarist1977 is offline guitarist1977
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I don't know if this was posted before, but NEVER EVER WORK ON THE AMPLIFIER IF YOU ARE TIRED. Not even soldering.

I remember I was quite tired but really wanted to complete the build that night. Finally I put everything together. Turned it on and bang - bias power capacitor blew up. Of course put it in a wrong polarity. I took another one put it in place. Turned on the amp and bang - same thing. Looked closer and of course I put it the wrong way one more time. Fortunately at this time I was out of capacitors so stopped working on it till the next day.

In this case nothing bad happened, but it could be much worse.
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Old 14th February 2019, 08:10 PM   #373
Funker is offline Funker  Germany
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Hi,

Quote:
When you have to measure at switched-off equipment, ALWAYS ground the HV to chassis, I saw accidents caused by people switching on equuipment not knowing that someone was testing!!
Grounding circuits and locking switches are mandatory here especially when the the switch/fuse is remote and not visible from the eqipment site.
To avoid someone else turn the circuit on while working on site/equipment , I got these professional warnings signs. Written in german saying " Do Not switch ! Danger!"

Here:
Safety Practices, General and Ultra-High Voltage

They stick magnetically to frames of amps /transmitters etc and at the door of the fuse box.

Fiddling in HV circuits is always danger. Working on it need to be always conscious with a clear mind. The best is reduce the work on powered equipment to a minimum. The most of alignment and trouble shooting works with only heaters and drive power while the HV is turned off.

voltages above 1kV are serious danger , every one work with it shoud exactly know what he do. Otherwise...


73
Wolfgang
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Old 19th February 2019, 03:03 AM   #374
trobbins is offline trobbins  Australia
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Wolfgang, often the remote upstream isolation device needs to be locked open, with the person working on downstream equipment holding the lock key.
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Old 19th February 2019, 08:53 AM   #375
Funker is offline Funker  Germany
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Quote:
Originally Posted by trobbins View Post
Wolfgang, often the remote upstream isolation device needs to be locked open, with the person working on downstream equipment holding the lock key.
Hi, that make sense.

73
Wolfgang
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