Solid Fuses: Visible Indicator If Blown?

[The Daring Dufas]

On 9/25/2013 9:09 AM, Ralph Mowery wrote:

I had a 100w, 150w and 200w bulbs that I soldered test leads with alligator clips to when I was working as a bench tech back when appliances and TV sets used a lot more power. In the past 20 years, most of the service work I've done has been mobile and not a good place to have glass bulbs bouncing around in a vehicle. I'm sorry but I keep assuming others would do what I do without thinking. The light bulb in series with a Simpson 260 was SOP when working on two way radios to check the DC current draw. A shunt was needed for AC current tests since those meters would only test up to 10 amps DC. A separate AC ammeter worked for bench testing. I had variable power supplies that indicated voltage and current being drawn by equipment when bench testing plus those power supplies had adjustable current limits that would drop voltage to zero when the limit was reached. The small resettable circuit breakers I used were put in series with the DMM when testing current draw. I repeat, never use a DMM to check current in line if you know it will exceed the safety limits of the meter. Test leads can melt or have the tips burned off. It's not a problem to put a DMM across a fuse when testing a radio being powered by a 12vdc power supply which is rated at 3 amps and has a built in circuit breaker like the small power supplies sold by Radio Shack for many years. It's been a while since I've been in a Radio Shack store to buy discrete components or batteries. If I'm working on a small AC appliance that would draw 5 amps/600 watts,(look at the label). The small circuit breaker in series with with a DMM having a 10 amp range is completely safe unless you are dumb enough (like me) to touch the exposed test clips and get a shock. Even if the small circuit breaker is not used and the appliance has a dead short, the 20 amp breaker supplying power to the outlet you are plugged into will trip. The small circuit breakers I once put together on my own are now sold at supply houses with the pigtails and test clip already on them. When repairing electrical or electronic gear, the best test equipment are your eyes, ears and nose. ^_^

TDD

[DerbyDad03]

re: "...unless you are dumb enough (like me) to touch the exposed test clips and get a shock."

...or the banana plug on the end of a jumper cable.

In my case it was the second week of USCG Electronics School training. On the worktable in front of us, we each had a 400 VDC power supply training device which was plugged into a power strip.

There was a ~4" jumper cable, with a banana plug on each end, that connected two sections of the power supply. The jumper could be pulled out to break the device down into smaller sections for troubleshooting training. Basically you were removing the load. The normal procedure was to shut the power supply down, pull the jumper and then power it back on.

Heck, I don't need to go through all that. I'll just hooked my finger into the loop and pull the cable out. So, with my forearm resting on the chassis, I hooked my finger into the jumper and pulled. Too bad one banana plug (on the output side) was a lot looser then the other one. With input side still plugged in, the loose end flipped up and laid against my thumb. With my arm laying on the chassis (read: ground) I became the new load for the 400 VDC.

My arm spasmed and I couldn't pull it away from the chassis. Instinctively, I reached out my other hand to pushed the chassis away. All that accomplished was to cause the current to flow from one hand to the other through my upper body. I was holding a 30 lb power supply up off the table as if it was weightless, yelling "Turn if off! Turn it off!" as my whole upper body spasmed.

The guy at the table in front of me turned around and grabbed the power cord in an attempt to unplug the device. Unfortunately, the power strip was not secured to the table so it just came up with the cord. The guy next to me reached over and slapped the power strip back onto the table which unplugged the device.

I dropped (actually, threw) the power supply onto the floor and they drove me over to the infirmary for an EKG. Other than the burns on my hand, I was apparently OK.

When I came back to class the next day all of the power strips had been screwed down to the work surfaces and 2 other guys had quit electronics school after witnessing my near demise. They quit ET school and I went on to work on devices that had power supplies in the range of 25KVDC.

Luckily (?) I still have the scars on my hand to remind me of how stupid I was. I've been a lot more careful since then.

[The Daring Dufas]

On 9/25/2013 3:25 PM, DerbyDad03 wrote:

I remember having an arc jump from the anode cap of the horizontal output tube in a TV set to my hand when working on a set in front of a customer at the shop. I excused myself to go to the back room where I yelled @#*&%*%$#@&*%^#!!!!! I then came back into the shop and resumed work on the set in front of the customer who had an odd yet concerned look on her face. I've been shocked, zapped and burned more times than I can count but I never, ever let my guard down around high voltage high current power coming into a building. When I worked as an electrician, my superintendent got a tingle when using an old wooden hot stick while we were connecting some 4,160 volt pad mounted transformers for the underground electrical system we were building. If it had been 13.8kv I doubt he would have gotten just a tingle. All my ladders and push poles are fiberglass because one never knows what you can run into around power systems. I learned long ago to work on everything as though it was energized because it a good habit to get into. One thing I really hate is when I've been working in hot weather and because I sweat like a thunderstorm, I wind up soaking wet with all my clothing soaked and the sweat dripping on the floor. You can tell where I've been by the wet areas on the floor. In this condition, I've had my sweat soaked shirt tail touch a ground while I was working on a panel. Salt water and sweat conduct electricity very, very well. o_O

TDD

[clare]

I believe so. Skin effect is most pronounced at very high frequencies, and virtually non-existent at low frequencies and DC. A hollow conductor has 2 surfaces - not sure if the inner surface comes into play or not.

[clare]

As a kid I had salvaged a power supply out of an ancient TV that didn't use a flyback system - the main power transformer had taps from, IIRC, 3.5 volts to 25000 volts. The high voltage was at the opposite end from the low voltage. I needed the low voltage to test a small motor I was working on, but I grabbed the wires on the wrong end. I must mention the basement ceiling was something like 5 1/2 ft to the floor decking, about 42 inches to the bottom of the joists. I was just under six feet tall at the time. I straightened up fery quickly and my rock-hard skull caught the end of a nail that held the

1/4" unserlay to the sub-floor, and I popped the head of that nail through the linoleum flooring in the living room above.

[krw]

For all reasonable values of voltage and current, yes. At the extremes strange things tend to crop up.

[gregz]

In the 70's working at NASA tracking station, we used loran to track cesium clock drift. There was a special receiver for that. Loran C and D. The only other way to measure cesium clock, was for them to bring in a portable reference.

We also had cooled parametric preamplifier for the best noise performance. The hydrogen maser was for deep space tracking, and there was another simple transistor amplifier backup. Most amplifiers can be cooled to get better noise ratio.

Greg

[The Daring Dufas]

And as you get closer to Absolute Zero. ^_^

TDD

[The Daring Dufas]

OUCH!! How deep was the hole in your skull or have you always had a hard head? ^_^

TDD

[The Daring Dufas]

There was an atomic clock in one room of the mission control center I was involved in building, in another room was a liquid cooled Cray X-MP super computer. That was 1988, I read somewhere a few years back that the university had a Cray X-MP they were trying to give away. ^_^

TDD

[DerbyDad03]

...snip...

Ahh...the circle of life.

The timing equipment that created the Loran signal was controlled by a cesium beam oscillator.

We Loran techs sent out a really, really well timed signal so you could use it to track drift on the same type of clock that was used to create the signal. Cool!

Based on this timeline, Loran D went out of service in the late 60's. Are you sure it was Loran D that you used in the 70?s? Loran C was used before and after that timeline. I never dealt with Loran D, only A and C.

...snip...

[clare]

It bled a bit, but I guess I've always been a bit hard headed. If anyone told be I had rocks in my head, I'd just take it for granite.

[gregz]

I'm pretty sure D, and I think it was an experimental station, and pretty close by. The loran still drifts around. Only long term average was used.

I read D was a short range high accuracy, and portable.

Greg

[Stormin Mormon]

Sounds miserable. I'd not want to hit a nail with my head, in any situation.

. Christ> >

=====================================

20 Items to Hoard Check list When a crisis is brewing, making a comprehensive list of supplies is no easy task? neither is purchasing them. As panic spreads, super market shelves will be stripped bare in a matter of hours. Contrary to popular belief, super markets don?t have tons of excess inventory. What you see on the shelves is what they?ve got in most cases. We see it almost every time a major hurricane targets a populated area. Desperate shoppers buy up every last can of beans, flashlight, and bottled water in a 50-mile radius. If you?re smart, you won?t be standing in line at the grocery store when the SHTF. You?ll already have that taken care of? Because you?ve read through this checklist to make sure you have everything your family needs to survive a crisis. Here are our Top 20 Items to Hoard:

1. Rice ? Dried rice has an incredibly long shelf life, making it ideal for storage. In nutritional terms, rice is rich in starch and carbohydrates. It?s also a good source of Vitamin B, iron, and protein.
2. Beans, Lentils, Black-eyed peas ? Legumes are a great source of protein, iron, and dietary fiber. Like rice, which they?re traditionally served with, dried beans have an exceptionally long shelf life.
3. Candles ? You?ll probably never read a disaster preparedness list that doesn?t include candles, and for good reason. A good stock of slow-burning emergency candles is a survival essential, as well as something to light them with.
4. Cigarette Lighters ? I recommend stashing a combo pack of at least 6 lighters in your stockpile. In a power outage, these guys can become very, very important. The can also be very easy to misplace.
5. Pasta ? Pasta stores well, has a long shelf life, and it?s loaded with carbohydrates. It?s also easy to prepare. Not to mention, pasta pairs well with lots of other items on this list.
6. Peanut Butter ? Hoarded by everyone from college students to doomsday survivalists, and for many of the same reasons, peanut butter is a tasty, shelf stable source of protein that pairs with lots of other items.
7. Can Opener/Multi-Tool ? It?s a good idea to carry a survival knife, but it?s a great idea to carry a quality multi-tool, like a Leatherman. A Leatherman comes in handy almost every day under normal circumstances and could be used as a weapon in a pinch.
8. Dried fruits, such as raisins, apricots, and papaya ? Dried fruits are a great source of nutrients, calories, potassium, and fiber. They can also be added to nuts to make delicious trail mixes.
9. Energy bars ? Since these bars are typically loaded with carbs and protein by design, they?re actually a good choice for your survival storage (maximum nutrition with minimal effort and prep).
10. Canned soups and chili ? Canned soups are easy to prepare and offer a nice variety of ingredients for the effort. Look for low-sodium options. Premium brands may be healthier, but value brands will make your money go further.
11. Gauze/Bandages ? For more serious injuries, you?ll want to keep a supply of dedicated gauze and bandages.
12. Rubbing Alcohol ? Rubbing alcohol burns on an open wound, but it is a great way to sterilize instruments, surfaces, and the skin surrounding a wound.
13. Batteries ? Obviously, you?ll need to coordinate your battery storage plan with any of the flashlights, radios, or other devices you may keep in your emergency stockpile. Batteries will last longest in cool dry conditions, but should be rotated out of your emergency supply on a yearly basis.
14. Toilet Paper ? Running out of toilet paper is annoying in any situation. But you certainly don?t want to run out in a shelter-in-place crisis scenario. My advice is to get more than enough. Life can get messy.
15. Trash Bags ? Trash will still need to be properly disposed of, even in a crisis. In fact, trash bags are even more important in a crisis. If running water is unavailable, trash bags may have to double as a toilet. Don?t skimp here.
16. Firearms ? Last but certainly not least, you?re going to need some type of weapon, just in case. It doesn?t have to be a gun, but then again what else are you willing to risk your family?s safety on, a sword? Pepper spray?
17. Drinking Water ? Most experts recommend a 2-week supply of water in your emergency storage. A 72-hour supply is the bare minimum. A water filter can help you extend you supply by allowing you to reuse cooking water.
18. Hand-Crank Radio ? Hand crank radios offer the ability to listen to important communications when power and cell networks are down. Some hand crank radios even offer a USB charging functionality.
19. Camp Stove ? There are a million options available for this purpose ? everything from handy backpacking stoves to heavy-duty outdoor ranges ? but it?s hard to beat the old self-contained Coleman camp stove.
20. Flashlights ? When it comes to flashlights, I have two recommendations, and neither one is expensive. First, find a comfortable LED headlamp. Second, rather than finding the brightest, most high-tech available, invest in a Maglite that runs on simple AA batteries.

[Stormin Mormon]

I'd not want a free atomic anything... too much hazmat disposal fee.

. Christ> >>> >>>>> Letter Re: Manual Hair Clippers

Permalink | Print

Jim, I enjoy your blog very much, have been following it for years. Keep up the good work.

On the many lists of items preppers are encouraged to obtain, I have never seen hair clippers suggested. An essential item. (By hair clippers I mean manual, not electric.) - Pastor D.

*JWR Replies:* Although they are probably still made in India and China, the best place to find traditional clippers is /used/, via eBay or Craigslist. If they are well-made and aren't rust-pitted, even a century-old pair of clippers will probably last/another /century. Just be sure to keep them well-oiled.

Subject: By The Spirit From: Stormin Mormon Date:

8/15/2013 9:24 AM Newsgroups: alt.survival

The LDS folks have an expression "by the Spirit". When there is a big decision to make, we pray and listen for the guidance of the Spirit.

And sometimes in every day life, we are prompted BTS to do this or that. Yesterday was such a day. It was lunch time, and I was out to buy pure gas if I could find it, and also to get some to eat.

BTS, I was prompted to go to a particular pizza shop. The last time there, the pizza was burnt around the edge, and I didn't much enjoy it. But, so, the Spirit is prompting and there I went.

The TV was on, and the woman was behind the counter. The over head lights were off, plenty of sunshine coming in the windows. I remarked how they were having a cool afternoon with the lights off, and doors open. No, she says, the power is off. For some odd reason the TV and cash register are fine, but the lights and all the refrigeration is down.

Asked if they had any slices, and they did. Cashed out.

As I got back into my truck, I realized why I was here. I have a bunch of promo flashlights with advertising. So, I took a couple back into the store, and gave to the woman at the cash register. She loved it! Said she had a light on her keyring, but no longer has the same keyring.

So, I got a perfectly cooked slice of pizza, she got a keyring light, and she says they have some work for me, coming up. The power is out, and I'm handing out flashlights. What's the odds?

[gregz]

Atomic does not necessarily mean it's radioactive.

Greg

[Dean Hoffman]

The Norwegians have an experimental thorium reactor working. Article here:

I guess there is less waste and it only has to be stored for 300 years in some type of radiation containment structure.

[sam E]

Atomic really means "indivisible".