Home |
Search |
Today's Posts |
|
Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
Â* A few months ago we had a power surge or something , blew out all the
electronic ballasts in my shop fluorescent lights . I've been limping along ... Today I received via the USPS a box containing 10 four foot LED tubes ... six of which are now installed in my fixtures and lighting my shop . Simple changes to the fixtures , hot lead to one end and neutral to the other (both pins) and bang we got light ! A lot brighter and a different color/temperature but that I can get used to . I got the clear tubes , upon reflection I might have gone diffused ... a piece of scotch tape will test that . Bottom line is for under 5 bucks a tube , they don't cost that much more than a fluorescent tube and they'll save me some bucks down the road in lower energy bills . And I used the fixtures I already had . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! |
#2
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On 9/19/2018 3:07 PM, Terry Coombs wrote: A few months ago we had a power surge or something , blew out all the electronic ballasts in my shop fluorescent lights . I've been limping along ... Today I received via the USPS a box containing 10 four foot LED tubes ... six of which are now installed in my fixtures and lighting my shop . Simple changes to the fixtures , hot lead to one end and neutral to the other (both pins) and bang we got light ! A lot brighter and a different color/temperature but that I can get used to . I got the clear tubes , upon reflection I might have gone diffused ... a piece of scotch tape will test that . Bottom line is for under 5 bucks a tube , they don't cost that much more than a fluorescent tube and they'll save me some bucks down the road in lower energy bills . And I used the fixtures I already had . I've got 8 foot dual tube cans in my shop, and the florescent tubes work just fine. However, my last trip over to a local store found me buying what may well be the last case they will ever stock. I expect I'll be forced to replace or rewire all my cans eventually myself, but none of the places I checked had LED tubes at anywhere near the price yours cost. Care to share your source. Also, let us know how they do after a few years. I replaced all the bulbs in my office and machine room with Leeson LED bulbs and the first one died within a few months. I think I've more than half, and I only got them a couple years ago. I originally got a lot more than I would need, and I am down to just one or two spares. Needless to say I'll be looking for another brand of LED bulbs next time. |
#3
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Thursday, September 20, 2018 at 6:12:51 PM UTC-4, Bob La Londe wrote:
I've got 8 foot dual tube cans in my shop, and the florescent tubes work just fine. However, my last trip over to a local store found me buying what may well be the last case they will ever stock. I expect I'll be forced to replace or rewire all my cans eventually myself, but none of the places I checked had LED tubes at anywhere near the price yours cost. Care to share your source. Also, let us know how they do after a few years. I replaced all the bulbs in my office and machine room with Leeson LED bulbs and the first one died within a few months. I think I've more than half, and I only got them a couple years ago. I originally got a lot more than I would need, and I am down to just one or two spares. Needless to say I'll be looking for another brand of LED bulbs next time. I did a quick search on 8 foot LED tubes, and they are available from a number of sources. Did not check prices as I expect they will cost less when you need them. Dan |
#4
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Thu, 20 Sep 2018 15:12:50 -0700, Bob La Londe
wrote: On 9/19/2018 3:07 PM, Terry Coombs wrote: A few months ago we had a power surge or something , blew out all the electronic ballasts in my shop fluorescent lights . I've been limping along ... Today I received via the USPS a box containing 10 four foot LED tubes ... six of which are now installed in my fixtures and lighting my shop . Simple changes to the fixtures , hot lead to one end and neutral to the other (both pins) and bang we got light ! A lot brighter and a different color/temperature but that I can get used to . I got the clear tubes , upon reflection I might have gone diffused ... a piece of scotch tape will test that . Bottom line is for under 5 bucks a tube , they don't cost that much more than a fluorescent tube and they'll save me some bucks down the road in lower energy bills . And I used the fixtures I already had . I've got 8 foot dual tube cans in my shop, and the florescent tubes work just fine. However, my last trip over to a local store found me buying what may well be the last case they will ever stock. I expect I'll be forced to replace or rewire all my cans eventually myself, but none of the places I checked had LED tubes at anywhere near the price yours cost. Care to share your source. Also, let us know how they do after a few years. I replaced all the bulbs in my office and machine room with Leeson LED bulbs and the first one died within a few months. I think I've more than half, and I only got them a couple years ago. I originally got a lot more than I would need, and I am down to just one or two spares. Needless to say I'll be looking for another brand of LED bulbs next time. I replaced the fluorescents in my shop with a case of 20 frosted 6500K 40W 8 footers from this guy last Feb. www.ebay.com/itm/301995907066 One half of one lamp failed within a few weeks, but that's a minor complaint compared to the increased light, decrease in the electric bill, and elimination of the magnetic ballast buzz. The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. It took no more than a couple hours to remove the magnetic ballasts and rewire the 10 fixtures. Took a little longer to get used to the color change. Now the places that still have the CW fluorescents look dingy to me. We replaced the 4 foot T8's in my wife's studio about a year ago with 10 lamps from this ebay seller. No failures to date. https://www.ebay.com/usr/minidavy?_t...72.m2749.l2754 It seem prices have stabilized or gone up a bit since my two purchases. -- Ned Simmons |
#6
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Thursday, September 20, 2018 at 5:32:27 PM UTC-7, Ned Simmons wrote:
The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. Maybe not so stupid. The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. The failure rate for a series string of seven is 0.1 of the rate for a string of 70. And, one string failing doesn't stop the other parallel strings from making light. Best practice for designing LED fixtures is not compatible with reusing the fluorescent fixtures unballasted OR with the original fluorescent ballasts. GE makes LED fluorescent-tube-shaped lamps labeled "Use only with General Electric LED21T8 DR/.... LED driver" |
#7
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd
wrote: On Thursday, September 20, 2018 at 5:32:27 PM UTC-7, Ned Simmons wrote: The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. Maybe not so stupid. The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. That implies about 175V across the 75W lamp once it's running. Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. I'll bet I've spent as much time over the years replacing ballasts as lamps. I'd rather spend the time up-front pulling them out. -- Ned Simmons |
#8
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On 9/21/2018 7:36 PM, Ned Simmons wrote:
On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: On Thursday, September 20, 2018 at 5:32:27 PM UTC-7, Ned Simmons wrote: The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. Maybe not so stupid. The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. That implies about 175V across the 75W lamp once it's running. Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. I'll bet I've spent as much time over the years replacing ballasts as lamps. I'd rather spend the time up-front pulling them out. Â*My only mistake was ordering the clear instead of frosted , these are pretty bright and tend to glare a bit . I tested it , and a strip of (frosted) scotch tape over the center of the clear side of the bulb is just about right . These are 6000K light temp LEDs , taking a bit to get used to after having less-than-enough light that was a lot more "yellow" . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! |
#9
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Fri, 21 Sep 2018 19:49:46 -0500, Terry Coombs
wrote: On 9/21/2018 7:36 PM, Ned Simmons wrote: On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: On Thursday, September 20, 2018 at 5:32:27 PM UTC-7, Ned Simmons wrote: The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. Maybe not so stupid. The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. That implies about 175V across the 75W lamp once it's running. Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. I'll bet I've spent as much time over the years replacing ballasts as lamps. I'd rather spend the time up-front pulling them out. *My only mistake was ordering the clear instead of frosted , these are pretty bright and tend to glare a bit . I tested it , and a strip of (frosted) scotch tape over the center of the clear side of the bulb is just about right . These are 6000K light temp LEDs , taking a bit to get used to after having less-than-enough light that was a lot more "yellow" . I ADORE the whiter LEDs and hated the ****-yellow incan color, so it was an easy swap for me. I sure like the newer pricing on LED fluor replacement strips but haven't partaken yet. -- America rose from abnormal origins. The nation didn't grow organ- ically or gradually from indigenous tribes--like, say, the French or the Poles--but emerged out of courageous, conscious acts of will by Pilgrims and Patriots. --Michael Medved, Right Turns |
#10
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Friday, September 21, 2018 at 5:36:05 PM UTC-7, Ned Simmons wrote:
On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: ... The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. The LEDs are more efficient, but the ballast still chokes current at circa 425 mA. So, the voltage is lower for LEDs than for tubes. My '24V' number is only order-of-magnitude. ...Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. But, it IS buffering the LEDs from voltage spikes, without the power-wasting resistors used in some lamp-replace series strings. The starter-boost is a complex part of the ballast, but isn't required for the LEDs; if it fails, you'll never notice. The 'internal LED drivers' in the one lamp I dissected, were... only rectifiers to prevent reverse voltage. |
#11
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On 9/22/2018 12:56 AM, John Doe wrote:
If this poster had a brain... Its "relamping the shop (to save electricity)" would consist of purchasing a high-quality modern headlamp. I'm dead serious. Nothing aids vision (while saving HUGELY on electricity as a SECONDARY benefit) more than a good headlamp. Couldn't live without mine. Â* If I were so broke couldn't afford to keep the power on I might do that too . I didn't relamp to "save electricity" , but to have usable levels of light . Oh , and if you have to resort to insults , **** off . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! |
#12
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Fri, 21 Sep 2018 20:36:11 -0400, Ned Simmons
wrote: On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: On Thursday, September 20, 2018 at 5:32:27 PM UTC-7, Ned Simmons wrote: The LED 8-footers available locally were drop-in replacements for the fluorescent tubes, i.e., require the ballast to operate. Stupid. The lamps I purchased connect directly across the line. Maybe not so stupid. The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. That implies about 175V across the 75W lamp once it's running. Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. I'll bet I've spent as much time over the years replacing ballasts as lamps. I'd rather spend the time up-front pulling them out. I have read in more than one place that dimmable LED lamps can better handle power fluctuations. Where I live we have 250 volts most of the time with occasional excursions above and rarely below 250. So I have been installinf only dimmable types. Haven't had any failures yet except for a cheap night light. That wasn't dimmable. Eric |
#13
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Fri, 21 Sep 2018 22:11:47 -0700 (PDT), whit3rd
wrote: On Friday, September 21, 2018 at 5:36:05 PM UTC-7, Ned Simmons wrote: On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: ... The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. The LEDs are more efficient, but the ballast still chokes current at circa 425 mA. So, the voltage is lower for LEDs than for tubes. My '24V' number is only order-of-magnitude. Which means the LED driver in the tube has to deal with a constant current source that can deliver up to 750 volts instead of a well-behaved 120V constant voltage source. Doesn't seem advantageous to me. ...Now, in addition to the internal LED driver(s) in the lamp, you have a point of failure, the ballast, that's not doing anything useful. But, it IS buffering the LEDs from voltage spikes, The ballast is intentionally designed to develop a 750V spike. without the power-wasting resistors used in some lamp-replace series strings. I've not seen dropping resistors in the replacement tubes. All I've seen have switching LED drivers. Look at the specs for the LED replacement tubes I pointed to. They run on 100-265VAC or 85-265VAC. The starter-boost is a complex part of the ballast, but isn't required for the LEDs; if it fails, you'll never notice. Perhaps for an electronic ballast, not so for a magnetic ballast. The 'internal LED drivers' in the one lamp I dissected, were... only rectifiers to prevent reverse voltage. I don't understand. Why would you need to protect an LED from reverse voltage? -- Ned Simmons |
#14
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Saturday, September 22, 2018 at 4:49:35 PM UTC-7, Ned Simmons wrote:
On Fri, 21 Sep 2018 22:11:47 -0700 (PDT), whit3rd wrote: On Friday, September 21, 2018 at 5:36:05 PM UTC-7, Ned Simmons wrote: On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: ... The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. The LEDs are more efficient, but the ballast still chokes current at circa 425 mA. Which means the LED driver in the tube has to deal with a constant current source that can deliver up to 750 volts instead of a well-behaved 120V constant voltage source. A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. The ballast is intentionally designed to develop a 750V spike. Yes, in order to light the cold tube; but, it does that when the tube is NOT conducting, when that potential 425 mA of current isn't drawn. LEDs without a 'driver' attached will always draw that current. I've not seen dropping resistors in the replacement tubes. All I've seen have switching LED drivers. Do you mean drivers built into the long tubes? I've never seen that. Look at the specs for the LED replacement tubes I pointed to. They run on 100-265VAC or 85-265VAC. The starter-boost is a complex part of the ballast, but isn't required for the LEDs; if it fails, you'll never notice. Perhaps for an electronic ballast, not so for a magnetic ballast. There's different designs, including some with heaters/neon lamps etc. The 'internal LED drivers' in the one lamp I dissected, were... only rectifiers to prevent reverse voltage. I don't understand. Why would you need to protect an LED from reverse voltage? Reverse voltage can create large (surface) electric fields, and move impurities around. That causes the LED to age, dim prematurely. Forward voltage on the diode never exceeds 3V, because the diode conducts, and that means the surface fields are smaller. |
#15
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On 9/23/2018 5:34 AM, Jim Wilkins wrote:
"John Doe" wrote in message news In fact, there is no better light source than a headlamp. Apparently some people object because it looks nerdy. Modern headlamps are extremely light, extremely BRIGHT (choose your color), and long-lasting, with no need for an external power supply. That's why "broke" surgeons use them. Bozo supplies its shop with "what I can afford" instead of what works. Bozo needs to learn how to read BIG LETTERS, too, I said saving electricity is a "SECONDARY" benefit of using a high-quality modern headlamp. On 9/22/2018 12:56 AM, John Doe wrote: If this poster had a brain... Its "relamping the shop (to save electricity)" would consist of purchasing a high-quality modern headlamp. I'm dead serious. Nothing aids vision (while saving HUGELY on electricity as a SECONDARY benefit) more than a good headlamp. Couldn't live without mine. ¶ÿ If I were so broke couldn't afford to keep the power on I might do that too . I didn't relamp to "save electricity" , but to have usable levels of light . Oh , and if you have to resort to insults , **** off . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! IIRC you don't use machine tools or need to protect yourself from their flying chips with a face shield. Â* I doubt he even knows what a "machine tool" is . Most trolls know very little but what their masters tell them to say . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! |
#16
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Sun, 23 Sep 2018 07:13:09 -0500, Terry Coombs
wrote: On 9/23/2018 5:34 AM, Jim Wilkins wrote: "John Doe" wrote in message news In fact, there is no better light source than a headlamp. Apparently some people object because it looks nerdy. Modern headlamps are extremely light, extremely BRIGHT (choose your color), and long-lasting, with no need for an external power supply. That's why "broke" surgeons use them. Bozo supplies its shop with "what I can afford" instead of what works. Bozo needs to learn how to read BIG LETTERS, too, I said saving electricity is a "SECONDARY" benefit of using a high-quality modern headlamp. On 9/22/2018 12:56 AM, John Doe wrote: If this poster had a brain... Its "relamping the shop (to save electricity)" would consist of purchasing a high-quality modern headlamp. I'm dead serious. Nothing aids vision (while saving HUGELY on electricity as a SECONDARY benefit) more than a good headlamp. Couldn't live without mine. ¶ÿ If I were so broke couldn't afford to keep the power on I might do that too . I didn't relamp to "save electricity" , but to have usable levels of light . Oh , and if you have to resort to insults , **** off . -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! IIRC you don't use machine tools or need to protect yourself from their flying chips with a face shield. * I doubt he even knows what a "machine tool" is . So far so good. The contraptions he's posted in the past demonstrate a need to learn how to weld at the very least. He's a dopey slow learner, so if he ever does learn to weld he'll be old like me by then and maybe he'll figure out what a great advantage it is to have a small headlamp on a welding helmet, a headlamp for every other task, bright shop lighting, bright task lighting, and white walls and ceiling. Most trolls know very little Same thing you said about me. You're demonstrating your own cognitive limitations. but what their masters tell them to say . LOL Who are these "masters?" It's clear that JD has very few fabricating skills, limited imagination, and is a top-posting bozo. His fascination with cordless drills makes me think of how cavemen might have responded to seeing a bag of marbles. His projects might impress the least-mechanically inclined high schoolers, but that's about it. Those are facts. So if you want to insult him, why go beyond the obvious by posting your own delusions? BTW, if he lived near me I'd offer to teach him some stuff. First thing I'd do is walk him over to my 16" gear-head, and set him up with a big chunk of rubber to turn at high speed while wearing a baggy protective kimona. Then I'd get him onto welding while using "tactile" gloves with all the finger tips cut off. After that maybe set him loose on out of position wrench turning of seized fasteners such that his teeth are in the line of fire. Only after he gets up to speed on all that would I show him how to fast charge his drill batteries using a patch cord into an AC socket. |
#17
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Mon, 24 Sep 2018 15:55:56 -0000 (UTC), John Doe
wrote: My cordless drill powered electric front wheel drive bike is probably the lightest electric bike there is for the power and distance. Some have tried using a drill to power the sprocket, but I believe mine is the first to use a freewheeling pedal hub. It is exceptionally versatile and very durable. Now DeWalt produces 9 amp hour batteries for it. https://www.flickr.com/photos_user.g...27532210%40N04 Your stuff was cute when I first saw it. And I'm generally supportive of kids even if all they're doing is trying. But you have progressed little, and spent too much time being annoying and witless. As someone skilled with machine tools, you can do better? I won't hold my breath waiting for it. Among the many things I've built is an entire aircraft. I could never have gotten any of it done if I'd been too busy uploading pics of Gillian Anderson and insisting that a headlamp was a substitute for good shop lighting. WTF? I agree that this poster knows much more about welding than I ever will. I spent most of my adulthood learning about computers. And yet you never learned not to top-post on Usenet. The idea it knows more about electricity and charging batteries than I do is laughable. I've lived off-grid. And my welding during that period was powered by inverters and batteries. You are an idiot to pretend you have more skill than old farts like me. I was doing more impressive fabrication when I was 14 than you are now. I was sneaking into my dad's garage when he was at work, and whittling down his puny supply of electrodes, which he was only superficially ****ed about. I was cobbling together go carts and mini bikes at the time powered by an old pedal-start washing machine engine. I knew right away that I needed to learn to weld, which is something that seems to have escaped you, along with the fact you could have learned in less time than you've spent yapping online. It's tough guy on the Internet chest-thumping went a little too far. Then why are you still doing it, feeb? Less annoying witlessness and more doing and you'd be much farther along. Although I sense you're not very ambitious, and the main goal is to get some attaboys. Good luck with that. |
#18
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On 9/24/2018 1:17 PM, John Doe wrote:
I post in context when I feel like it, at least when I'm dealing with non-trolls. I'm not into production, I am into design. This tough guy on the Internet continues to beat its chest but fails to answer my challenge. If it thinks it can do better than my electric bike design, let's see it... https://www.flickr.com/photos_user.g...27532210%40N04 No idea what "Gillian Anderson" is about, maybe just another "fabrication"... Â* Who exactly are you accusing of "beating his chest" ? And what "challenge" are you talking about ? As far as your bike thingy , it takes little imagination and even less skill to drill a few holes in some stock aluminum plate and gob on the hot melt glue to hold a cable in place . My chops ? Ain't got none . Unless you count a micrometer adjust dovetail slide boring head , or maybe a home designed/built taper attachment for my machine lathe (also micrometer adjust), or possibly even the 9:1 reduction gear set I made when I was going to build my own X axis power feed for my milling machine - including cutting the gears . BTW , none of those projects required the use of a headlamp ... -- Snag Yes , I'm old and crochety - and armed . Get outta my woods ! |
#19
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Mon, 24 Sep 2018 18:17:44 -0000 (UTC), John Doe
wrote: I post in context when I feel like it, I'm confident you'll keep doing what you "feel like," no matter how dumb it is. at least when I'm dealing with non-trolls. You're a dopey top-poster. You're pigheaded to keep doing it. I'm not into production, I am into design. Not much design there. In fact, marrying two existing things is generally the opposite of design. Chocolate and peanut butter combinations excepted, of course. This tough guy on the Internet continues to beat its chest but fails to answer my challenge. If it thinks it can do better than my electric bike design, let's see it... Dopey challenge. I stopped being interested in bicycles about 50 years ago. I found that pretty much any other vehicle expanded my range quite a bit. Especially aircraft, which tend to have more design and fabrication requirements in a single sub-system than you've done in your entire life. https://www.flickr.com/photos_user.g...27532210%40N04 No idea what "Gillian Anderson" is about, My mistake, it's the somewhat similar looking Lauren Holly, and a crotch shot of Maria Sharapova. Are there drill batteries hiding between her legs? The cat doesn't look impressed at all, time for you to drill-motorize a cardboard box I guess. The point remains, you can use your time to yap or to progress. You've made your choice and I'm happy you're here for me to poop on. maybe just another "fabrication"... Nobody's surprised that you're proving my point by posting more lameness. Why do you keep adding "free spam" to the group list? Was that something you learned to do in 'puter school? |
#20
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Mon, 24 Sep 2018 13:59:05 -0500, Terry Coombs
wrote: On 9/24/2018 1:17 PM, John Doe wrote: I post in context when I feel like it, at least when I'm dealing with non-trolls. I'm not into production, I am into design. This tough guy on the Internet continues to beat its chest but fails to answer my challenge. If it thinks it can do better than my electric bike design, let's see it... https://www.flickr.com/photos_user.g...27532210%40N04 No idea what "Gillian Anderson" is about, maybe just another "fabrication"... * Who exactly are you accusing of "beating his chest" ? And what "challenge" are you talking about ? As far as your bike thingy , it takes little imagination and even less skill to drill a few holes in some stock aluminum plate and gob on the hot melt glue to hold a cable in place . My chops ? Ain't got none . Unless you count a micrometer adjust dovetail slide boring head , or maybe a home designed/built taper attachment for my machine lathe (also micrometer adjust), or possibly even the 9:1 reduction gear set I made when I was going to build my own X axis power feed for my milling machine - including cutting the gears . That was overkill. Pretty sure I was ahead of his skill level when I built a wishing well out of popsicle sticks in after-Sunday-School-class. BTW , none of those projects required the use of a headlamp ... I love my headlamps. Can hardly believe the improvement it made adding a small one to my welding helmet. My all-day ones are powered by 18650s. Saves me cleaning the smoke off the overheads as often. |
#21
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd
wrote: On Saturday, September 22, 2018 at 4:49:35 PM UTC-7, Ned Simmons wrote: On Fri, 21 Sep 2018 22:11:47 -0700 (PDT), whit3rd wrote: On Friday, September 21, 2018 at 5:36:05 PM UTC-7, Ned Simmons wrote: On Fri, 21 Sep 2018 12:59:12 -0700 (PDT), whit3rd wrote: ... The 'require ballast' lamps get about 24V of excitation, which means seven or eight LED diodes in a series string, with other strings in parallel. The 'full voltage' get 240V, so that's seventy or eighty in series. Where do you get 24V? A standard ballast for 8 foot F96T12 lamps outputs 750V for starting the lamp and 425mA operating. The LEDs are more efficient, but the ballast still chokes current at circa 425 mA. Which means the LED driver in the tube has to deal with a constant current source that can deliver up to 750 volts instead of a well-behaved 120V constant voltage source. A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. And if you implement a single string connected directly to the ballast, LEDs that'll operate at 425mA are expensive, require relatively heavy heat sinks, and will present difficult-to-diffuse bright point sources. Approx 30 LED's vs. 196 in the replacement tubes I purchased. The ballast is intentionally designed to develop a 750V spike. Yes, in order to light the cold tube; but, it does that when the tube is NOT conducting, when that potential 425 mA of current isn't drawn. LEDs without a 'driver' attached will always draw that current. I've not seen dropping resistors in the replacement tubes. All I've seen have switching LED drivers. Do you mean drivers built into the long tubes? I've never seen that. Look at the specs for the LED replacement tubes I pointed to. They run on 100-265VAC or 85-265VAC. The starter-boost is a complex part of the ballast, but isn't required for the LEDs; if it fails, you'll never notice. Perhaps for an electronic ballast, not so for a magnetic ballast. There's different designs, including some with heaters/neon lamps etc. The 'internal LED drivers' in the one lamp I dissected, were... only rectifiers to prevent reverse voltage. I don't understand. Why would you need to protect an LED from reverse voltage? Reverse voltage can create large (surface) electric fields, and move impurities around. That causes the LED to age, dim prematurely. Forward voltage on the diode never exceeds 3V, because the diode conducts, and that means the surface fields are smaller. -- Ned Simmons |
#22
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote:
On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. |
#23
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
Terry Coombs wrote:
none of those projects required the use of a headlamp WRONG! EVERYTHING requires the use of a headlamp. |
#24
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tuesday, September 25, 2018 at 12:47:35 AM UTC-4, John Doe wrote:
Terry Coombs wrote: none of those projects required the use of a headlamp WRONG! EVERYTHING requires the use of a headlamp. Some things require not using a headlamp. Arc welding requires a face mask which precludes the use of a headlamp. Dan |
#25
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd
wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons |
#26
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
"Ned Simmons" wrote in message
... On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons They are somewhat self-ballasting, as shown by the I-V curves. https://www.electronics-tutorials.ws/diode/diode_8.html |
#27
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tue, 25 Sep 2018 04:38:44 -0700 (PDT), "
wrote: Arc welding requires a face mask which precludes the use of a headlamp. Nonsense. I added a headlamp to my welding helmet about a year ago. It works so well that I'm surprised it isn't a popular commercial offering for old farts. It improved the view before the arc is struck. It cured the problem of temporary blindness due to the need for old eyes to refocus when the arc is first struck. It makes it easier to use the helmet for grinding. Yesterday I noticed those problems seemed to be returning somewhat. The light looked Ok but I couldn't remember when I last swapped the batteries. Put in fresh ones and things improved again. When I first tried adding a lamp to the helmet, I used an old 18650 model I had lying around. Nice and bright, but too heavy and required too many button pushes to switch on and off. Changed to a smaller one with a simple on/off switch. In short, a welding helmet light does all the things everybody knows a welding task light helps with, but puts the light easily right where it's needed. BTW, normally I don't share good tips with rightards. I'm making an exception here because I know that once some of you other old farts put a light on your welding helmet, it's going to make your teeth grind every time you remember that such a great improvement came from an alleged "leftist," who your buddy claimed he was having killed at least 6 years ago. chuckle |
#28
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tuesday, September 25, 2018 at 5:54:11 AM UTC-7, Ned Simmons wrote:
On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: ...you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? I prefer not to do it that way, but for a manufacturer, batch-matching of the LEDs is the first step. Designing the lamp so that all stay at similar temperatures is the second. Maybe, too, the LEDs are deliberatelyl degenerated somewhat (aren't ideal diodes). In similar situations, I've seen fuses used, which both add series resistance and which prevent a single shorted (failed) unit from causing a total failure. |
#29
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tue, 25 Sep 2018 09:15:10 -0400, "Jim Wilkins"
wrote: "Ned Simmons" wrote in message .. . On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons They are somewhat self-ballasting, as shown by the I-V curves. https://www.electronics-tutorials.ws/diode/diode_8.html Unless I'm misintrepeting the curves, or looking in the wrong place, the graph shows a potential for runaway -- the slope of the curves increases with increasing voltage. Here's a similar curve for a tungsten filament, which is self-ballasting. https://www.quora.com/What-does-the-...lamp-look-like This article talks about the hazards of paralleling strings of LEDs. https://www.ledsmagazine.com/article...-magazine.html -- Ned Simmons |
#30
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tue, 25 Sep 2018 12:08:10 -0700 (PDT), whit3rd
wrote: On Tuesday, September 25, 2018 at 5:54:11 AM UTC-7, Ned Simmons wrote: On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: ...you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? I prefer not to do it that way, but for a manufacturer, batch-matching of the LEDs is the first step. Designing the lamp so that all stay at similar temperatures is the second. Maybe, too, the LEDs are deliberatelyl degenerated somewhat (aren't ideal diodes). In similar situations, I've seen fuses used, which both add series resistance and which prevent a single shorted (failed) unit from causing a total failure. Or you could avoid the work-arounds and potential pitfalls: pitch the ballasts, and purchase lamps with built-in LED drivers that operate on line voltage. -- Ned Simmons |
#31
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tuesday, September 25, 2018 at 12:41:01 PM UTC-7, Ned Simmons wrote:
On Tue, 25 Sep 2018 12:08:10 -0700 (PDT), whit3rd wrote: On Tuesday, September 25, 2018 at 5:54:11 AM UTC-7, Ned Simmons wrote: On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: ...you can't just connect parallel strings of LED's Yet, it's done all the time. Or you could avoid the work-arounds and potential pitfalls: pitch the ballasts, and purchase lamps with built-in LED drivers that operate on line voltage. What kind of 'built-in LED drivers' are you thinking of? Gizmos that switch OPEN when the current goes too high? Or, complete current-regulated DC power supplies? Something as reliable as a magnetic ballast is not going to look like a silicon IC, and take AC line input, and spikes, gracefully. |
#32
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
"Ned Simmons" wrote in message
... On Tue, 25 Sep 2018 09:15:10 -0400, "Jim Wilkins" wrote: "Ned Simmons" wrote in message . .. On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons They are somewhat self-ballasting, as shown by the I-V curves. https://www.electronics-tutorials.ws/diode/diode_8.html Unless I'm misintrepeting the curves, or looking in the wrong place, the graph shows a potential for runaway -- the slope of the curves increases with increasing voltage. Here's a similar curve for a tungsten filament, which is self-ballasting. https://www.quora.com/What-does-the-...lamp-look-like This article talks about the hazards of paralleling strings of LEDs. https://www.ledsmagazine.com/article...-magazine.html -- Ned Simmons Try this: https://www.cree.com/led-components/...LA1BWKWMKW.pdf The slope isn't straight like a resistor voltage divider, the reason I qualified them as "somewhat". It also shows their limited tolerance for reverse bias. -jsw |
#33
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tue, 25 Sep 2018 13:32:13 -0700 (PDT), whit3rd
wrote: On Tuesday, September 25, 2018 at 12:41:01 PM UTC-7, Ned Simmons wrote: On Tue, 25 Sep 2018 12:08:10 -0700 (PDT), whit3rd wrote: On Tuesday, September 25, 2018 at 5:54:11 AM UTC-7, Ned Simmons wrote: On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: ...you can't just connect parallel strings of LED's Yet, it's done all the time. Or you could avoid the work-arounds and potential pitfalls: pitch the ballasts, and purchase lamps with built-in LED drivers that operate on line voltage. What kind of 'built-in LED drivers' are you thinking of? Gizmos that switch OPEN when the current goes too high? No. Or, complete current-regulated DC power supplies? Yes. I haven't pulled one apart, but I'm pretty confident that the replacement tubes I purchased have constant current switching power supplies. Something as reliable as a magnetic ballast is not going to look like a silicon IC, and take AC line input, and spikes, gracefully. I've been designing, building, and installing automation and machine tools in industrial settings for 35 years. For most of that time the bulk of the low power loads in control systems have been powered by switchers with universal inputs; typically 100-265VAC. I've seen very few failures, so it's possible to build such supplies that survive in nasty electrical environments. Another example is electronic fluorescent ballasts, which are only slightly less reliable than magnetic ballasts. The quality of the supplies in LED fluorescent replacements undoubtedly varies and is a legitimate question, but my experience so far has been more than satisfactory. -- Ned Simmons |
#34
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Tue, 25 Sep 2018 18:31:29 -0400, "Jim Wilkins"
wrote: "Ned Simmons" wrote in message .. . On Tue, 25 Sep 2018 09:15:10 -0400, "Jim Wilkins" wrote: "Ned Simmons" wrote in message ... On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons They are somewhat self-ballasting, as shown by the I-V curves. https://www.electronics-tutorials.ws/diode/diode_8.html Unless I'm misintrepeting the curves, or looking in the wrong place, the graph shows a potential for runaway -- the slope of the curves increases with increasing voltage. Here's a similar curve for a tungsten filament, which is self-ballasting. https://www.quora.com/What-does-the-...lamp-look-like This article talks about the hazards of paralleling strings of LEDs. https://www.ledsmagazine.com/article...-magazine.html -- Ned Simmons Try this: https://www.cree.com/led-components/...LA1BWKWMKW.pdf The slope isn't straight like a resistor voltage divider, the reason I qualified them as "somewhat". It also shows their limited tolerance for reverse bias. -jsw Yeah, it's sinking in. Slowly. -- Ned Simmons |
#35
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
"Ned Simmons" wrote in message ... On Tue, 25 Sep 2018 18:31:29 -0400, "Jim Wilkins" wrote: "Ned Simmons" wrote in message . .. On Tue, 25 Sep 2018 09:15:10 -0400, "Jim Wilkins" wrote: "Ned Simmons" wrote in message m... On Mon, 24 Sep 2018 19:30:37 -0700 (PDT), whit3rd wrote: On Monday, September 24, 2018 at 6:12:23 PM UTC-7, Ned Simmons wrote: On Sat, 22 Sep 2018 19:44:42 -0700 (PDT), whit3rd wrote: A constant current source is ideal for powering LEDs; with the right size LED (or the right multiplicity of paralleled LEDs) that's useful power. Sure, but you can't just connect parallel strings of LED's to a constant current source and expect the current in the individual strings will be equal. Yet, it's done all the time. A 'nine-LED' flashlight with three AAA cells has nine strings of one LED each, in parallel. Desk lamps with three or four LED strings in parallel are common, also. Sometimes resistors are added to each string, but not always. So how do you insure that the current is divided equally among the strings? -- Ned Simmons They are somewhat self-ballasting, as shown by the I-V curves. https://www.electronics-tutorials.ws/diode/diode_8.html Unless I'm misintrepeting the curves, or looking in the wrong place, the graph shows a potential for runaway -- the slope of the curves increases with increasing voltage. Here's a similar curve for a tungsten filament, which is self-ballasting. https://www.quora.com/What-does-the-...lamp-look-like This article talks about the hazards of paralleling strings of LEDs. https://www.ledsmagazine.com/article...-magazine.html -- Ned Simmons Try this: https://www.cree.com/led-components/...LA1BWKWMKW.pdf The slope isn't straight like a resistor voltage divider, the reason I qualified them as "somewhat". It also shows their limited tolerance for reverse bias. -jsw Yeah, it's sinking in. Slowly. -- Ned Simmons In the 1980's I designed and built a delicately balanced constant current string of LEDs, thermistors and Zeners that sensed and indicated four liquid ink levels in a rotating print head. It was a finely tuned version of the Low Fuel light in my car. At the time I understood the components' I-V curves well, but I haven't dealt as seriously with LEDs since. The constant current limiter was a depletion mode JFET with its gate connected to the source like example 7. They were available as 2-terminal devices that looked like diodes. https://www.quora.com/What-are-Fet-application -jsw |
#36
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Thu, 27 Sep 2018 21:04:13 -0400, "Jim Wilkins"
wrote: In the 1980's I designed and built a delicately balanced constant current string of LEDs, thermistors and Zeners that sensed and indicated four liquid ink levels in a rotating print head. It was a finely tuned version of the Low Fuel light in my car. At the time I understood the components' I-V curves well, but I haven't dealt as seriously with LEDs since. The constant current limiter was a depletion mode JFET with its gate connected to the source like example 7. They were available as 2-terminal devices that looked like diodes. https://www.quora.com/What-are-Fet-application -jsw For Centronics? I recall you mentioning Centronics because in the early 90's I designed a couple pieces of automation for Presstek in Hudson NH. Presstek was started by the Howards and many of the employees had also worked at Centronics. -- Ned Simmons |
#37
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
"Ned Simmons" wrote in message
... On Thu, 27 Sep 2018 21:04:13 -0400, "Jim Wilkins" wrote: In the 1980's I designed and built a delicately balanced constant current string of LEDs, thermistors and Zeners that sensed and indicated four liquid ink levels in a rotating print head. It was a finely tuned version of the Low Fuel light in my car. At the time I understood the components' I-V curves well, but I haven't dealt as seriously with LEDs since. The constant current limiter was a depletion mode JFET with its gate connected to the source like example 7. They were available as 2-terminal devices that looked like diodes. https://www.quora.com/What-are-Fet-application -jsw For Centronics? I recall you mentioning Centronics because in the early 90's I designed a couple pieces of automation for Presstek in Hudson NH. Presstek was started by the Howards and many of the employees had also worked at Centronics. -- Ned Simmons Same people, incorporated as "Howtek". That car, a 78 Accord, had several unusual electrical and mechanical features I was curious about, such as current-operated reed relays in series with the brake lights that lit an indicator if a bulb burned out. Its extremely lean burning CVCC engine gave it ~38MPG on average and up to 44MPG on a long trip. |
#38
Posted to rec.crafts.metalworking
|
|||
|
|||
Relamping the shop
On Saturday, September 22, 2018 at 1:56:12 AM UTC-4, John Doe wrote:
If this poster had a brain... Its "relamping the shop (to save electricity)" would consist of purchasing a high-quality modern headlamp. I'm dead serious. Nothing aids vision (while saving HUGELY on electricity as a SECONDARY benefit) more than a good headlamp. Couldn't live without mine. -- (snipped) What a wailing ****head. Who ****ed in your cheerios this morning, tough guy? |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Wood Shop Redux (the old shop *is* the new shop) Part 4- MakingSawdust ... once more | Woodworking | |||
Wood Shop Redux (the old shop *is* the new shop) Part 3- Drawers | Woodworking | |||
Wood Shop Redux (the old shop *is* the new shop) Part 2-Cheapplywood & recycled drawers | Woodworking | |||
Wood Shop Redux (the old shop *is* the new shop) Part 1-Storage Wall | Woodworking | |||
Why are schools dumping auto shop, wood shop, and metal shop? | Metalworking |