Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

Without knowing more details it's pure speculation really.

One thing I would mention that most people seem not to know is that the primary purpose of fuses and circuit breakers is to prevent the supply wiring from heating to the point it catches fire in the event of a short.
So called fast semiconductor fuses often included to "save" expensive semis like big IGBT packs etc rarely seem to work that way; maybe that's just poor design, but back when I was mending such things a blown fuse usually indicated a blown semi-pack...

It's generally taken that protecting fuses with semiconductors (sic) is a sign of naïvety in the designer of anything so constructed.

I contend that it's equally naive to expect fuses to protect any sand state device or component.

The 500ma fuse I installed in the Type 547 was to give a vacuum tube circuit a fighting chance in case of a short.

  [We need a emoticon of the sound of something going whoosh over someone's head]

You've just restated what I said, but in a less wry and witty way. The whole point of my remark was that trying to protect a semiconductor by putting a fuse in front of it just ends up with the semiconductor protecting the fuse. Even had the "sic" as a huge signpost that I literally meant what I said and that it wasn't a mis-phrasing.

[bd139]

philosophical argument: fuses exist to be replaced!

[med6753]

Without knowing more details it's pure speculation really.

One thing I would mention that most people seem not to know is that the primary purpose of fuses and circuit breakers is to prevent the supply wiring from heating to the point it catches fire in the event of a short.
So called fast semiconductor fuses often included to "save" expensive semis like big IGBT packs etc rarely seem to work that way; maybe that's just poor design, but back when I was mending such things a blown fuse usually indicated a blown semi-pack...

It's generally taken that protecting fuses with semiconductors (sic) is a sign of naïvety in the designer of anything so constructed.

I contend that it's equally naive to expect fuses to protect any sand state device or component.

The 500ma fuse I installed in the Type 547 was to give a vacuum tube circuit a fighting chance in case of a short.

  [We need a emoticon of the sound of something going whoosh over someone's head]

You've just restated what I said, but in a less wry and witty way. The whole point of my remark was that trying to protect a semiconductor by putting a fuse in front of it just ends up with the semiconductor protecting the fuse. Even had the "sic" as a huge signpost that I literally meant what I said and that it wasn't a mis-phrasing.

Well excuse me if I'm not as witty as you are and the whoosh over my head was lack of morning caffeine. 

Fucking engineers. 

[tautech]

Mom & Pop ISP we work closely with has a new project for me. 
Please make a mount to affix it to a pole (done and shit easy) and assemble this vertical helix 200W 24V wind alternator......instructions are crap, real crap  and the B&W illustration show bugger all detail of how the 6 tiers of blades are actually fastened  so went looking for assembly videos............


8 yes 8 sequential videos how to assemble the forking thing where at a few stages it appears extra sets of hands are needed ! 
FML

 

Tell me about it !
Trouble is our main 11 GHz data backhaul link is suffering if we have a run of bad weather or heavily overcast days and especially as the #'s of customers hanging off it grows and batteries are now struggling with the increased load despite there's a 3 full size solar panel array charging them so we need add some wind charging until we can reassign the backhaul load to other yet to be commissioned fiber links.
Such are the headaches of a small but successful wireless data provider.

A smaller adjacent relay installation crashed last week but an urgent installation of a 2nd solar panel fixed that after a few days of getting the batteries up to full charge again. Check out the charge rate ! 

[mnementh]

Yeah... the difference there is the difference in price. That one costs 4X as much as this little one. You can spend all sorts of money, depending on the features you want. I just got it because cheap as chips, and I'm already familiar with the kind of work they're talking aboot with my ESCs and PDBs.

If I let the magic smoke out, well... lesson learnt cheaply enuf. 

mnem
 

probably not 4x. I paid 20$ shipped. I'm still waiting for it though 

54 dollah... Next item in the list on Bang-em-good.    Evidently the word has gotten out.

mnem
 

[Robert763]

<SNIP>

I ordered something awfully similar. I'm planning to use it to make Type K thermocouple. I should also try to find some nickel strips to see how well it's working on batteries.

Edit: I did my homework before ordering and got the "Wise Maple" version that doesn't need to be fixed and should be working out of the box.

If welding thermocouples you need a carbon electrode. Using the copper or brass ones suppled with battery tab welders contaminates the alloy and can lead to inaccuracy.

I'm still not sure of the setup I'm going to use (will need to experiment a little bit), but was planning to use Nickel plated probes. If the plating is tick enough, I guess it will survive the process.

for alloy thermocouples any metal, even one that is part of the couple metalurgy could upset the accuracy due changing the alloy ratio.  For couples with pure element metals you can use one of them but it's still normal to use carbon as the second electrode with the two couple wires connected together. The wires should be positive when welding. Ideally they should also be shielded with Argon (small disposible bottles are available for hobby MIG welders).
Some fine wire type K thermocouples are welded wire to wire without another electrode.

[med6753]

Mom & Pop ISP we work closely with has a new project for me. 
Please make a mount to affix it to a pole (done and shit easy) and assemble this vertical helix 200W 24V wind alternator......instructions are crap, real crap  and the B&W illustration show bugger all detail of how the 6 tiers of blades are actually fastened  so went looking for assembly videos............


8 yes 8 sequential videos how to assemble the forking thing where at a few stages it appears extra sets of hands are needed ! 
FML

 

Tell me about it !
Trouble is our main 11 GHz data backhaul link is suffering if we have a run of bad weather or heavily overcast days and especially as the #'s of customers hanging off it grows and batteries are now struggling with the increased load despite there's a 3 full size solar panel array charging them so we need add some wind charging until we can reassign the backhaul load to other yet to be commissioned fiber links.
Such are the headaches of a small but successful wireless data provider.

A smaller adjacent relay installation crashed last week but an urgent installation of a 2nd solar panel fixed that after a few days of getting the batteries up to full charge again. Check out the charge rate ! 

That is hefty charge rate. No wonder the arrays can't keep up if you have bad weather.

[Cerebus]

Without knowing more details it's pure speculation really.

One thing I would mention that most people seem not to know is that the primary purpose of fuses and circuit breakers is to prevent the supply wiring from heating to the point it catches fire in the event of a short.
So called fast semiconductor fuses often included to "save" expensive semis like big IGBT packs etc rarely seem to work that way; maybe that's just poor design, but back when I was mending such things a blown fuse usually indicated a blown semi-pack...

It's generally taken that protecting fuses with semiconductors (sic) is a sign of naïvety in the designer of anything so constructed.

I contend that it's equally naive to expect fuses to protect any sand state device or component.

The 500ma fuse I installed in the Type 547 was to give a vacuum tube circuit a fighting chance in case of a short.

  [We need a emoticon of the sound of something going whoosh over someone's head]

You've just restated what I said, but in a less wry and witty way. The whole point of my remark was that trying to protect a semiconductor by putting a fuse in front of it just ends up with the semiconductor protecting the fuse. Even had the "sic" as a huge signpost that I literally meant what I said and that it wasn't a mis-phrasing.

Well excuse me if I'm not as witty as you are and the whoosh over my head was lack of morning caffeine. 

Fucking engineers. 

Fucking technicians, can't even follow the instructions.

1) Drink coffee.
2) Then, and only then, should you attempt any contact with the outside world.
3) If problems with the outside world persist, try whiskey instead.

[mnementh]

mnem

[tautech]

That is hefty charge rate. No wonder the arrays can't keep up if you have bad weather.

Not so much as the 390AH series pair were pretty low after going flat and the system crashing from insufficient charge. Their actual resting voltage that day way just 11V but with that amount of charge going in they showed 12.6V on our remote monitoring. The panel orientation on that installation is not optimal as we used the existing pipe framework after the site was abandoned yet we could possibly unbolt it and rotate it 90^o to have it more like it should be however for sure the bolt holes wouldn't line up and we'd need to drill more holes in the concrete bunker it's on. This but now with 2 panels:

[Kosmic]

Yeah... the difference there is the difference in price. That one costs 4X as much as this little one. You can spend all sorts of money, depending on the features you want. I just got it because cheap as chips, and I'm already familiar with the kind of work they're talking aboot with my ESCs and PDBs.

If I let the magic smoke out, well... lesson learnt cheaply enuf. 

mnem
 

probably not 4x. I paid 20$ shipped. I'm still waiting for it though 

54 dollah... Next item in the list on Bang-em-good.    Evidently the word has gotten out.

mnem
 

You can find cheaper on Ali flea market express. YougetBangedVeryGood is always a bit more expensive.

[mnementh]

Mom & Pop ISP we work closely with has a new project for me. 
Please make a mount to affix it to a pole (done and shit easy) and assemble this vertical helix 200W 24V wind alternator......instructions are crap, real crap  and the B&W illustration show bugger all detail of how the 6 tiers of blades are actually fastened  so went looking for assembly videos............
https://youtu.be/gBsDqGanGKA

8 yes 8 sequential videos how to assemble the forking thing where at a few stages it appears extra sets of hands are needed ! 
FML

 

Tell me about it !   Trouble is our main 11 GHz data backhaul link is suffering if we have a run of bad weather or heavily overcast days and especially as the #'s of customers hanging off it grows and batteries are now struggling with the increased load despite there's a 3 full size solar panel array charging them so we need add some wind charging until we can reassign the backhaul load to other yet to be commissioned fiber links.
Such are the headaches of a small but successful wireless data provider.

A smaller adjacent relay installation crashed last week but an urgent installation of a 2nd solar panel fixed that after a few days of getting the batteries up to full charge again. Check out the charge rate ! 

Good lord... that turbine design is like... made of fail. No way in hell you're ever going to get it anywhere close to balanced... seems to me it's gonna eat bearings like M&Ms.  Is that fustercluck supposed to be actual wind power, or more like some vaporware crap they make to sell fuckwit noobs when they get swept up in the whole "off the grid" craze...? 

If you're drawing charge current like that to recover... what is your typical load current, and how much has it changed since the original design scope? Does it really vary that much with demand? 

mnem

[Kosmic]

<SNIP>

I ordered something awfully similar. I'm planning to use it to make Type K thermocouple. I should also try to find some nickel strips to see how well it's working on batteries.

Edit: I did my homework before ordering and got the "Wise Maple" version that doesn't need to be fixed and should be working out of the box.

If welding thermocouples you need a carbon electrode. Using the copper or brass ones suppled with battery tab welders contaminates the alloy and can lead to inaccuracy.

I'm still not sure of the setup I'm going to use (will need to experiment a little bit), but was planning to use Nickel plated probes. If the plating is tick enough, I guess it will survive the process.

for alloy thermocouples any metal, even one that is part of the couple metalurgy could upset the accuracy due changing the alloy ratio.  For couples with pure element metals you can use one of them but it's still normal to use carbon as the second electrode with the two couple wires connected together. The wires should be positive when welding. Ideally they should also be shielded with Argon (small disposible bottles are available for hobby MIG welders).
Some fine wire type K thermocouples are welded wire to wire without another electrode.

Yes, wire to wire seem like a good approach. I'll try that, thanks.

[med6753]

3) If problems with the outside world persist, try whiskey instead.

Considering some of the ludicrous instructions I've received in my long career in dealing with engineers a shot or two of whiskey would have been a relief.     

[med6753]

Well of course here's FedEx, with their truck, making a delivery here at 11:30. But when it came to my package yesterday it was a contractor who delivered at 16:00. 

Oh well, at least I got it. 

[mnementh]

Yeah... the difference there is the difference in price. That one costs 4X as much as this little one. You can spend all sorts of money, depending on the features you want. I just got it because cheap as chips, and I'm already familiar with the kind of work they're talking aboot with my ESCs and PDBs.

If I let the magic smoke out, well... lesson learnt cheaply enuf. 

mnem
 

probably not 4x. I paid 20$ shipped. I'm still waiting for it though 

   54 dollah... Next item in the list on Bang-em-good.    Evidently the word has gotten out.

You can find cheaper on Ali flea market express. YougetBangedVeryGood is always a bit more expensive.

Sometimes. I'm finding lately that they are in fact as expensive or more expensive than what I can find on bg or slAmazon. The vendors on AliEx definitely do the "sliding scale pricing depending on demand" thing... sometimes changing from hour to hour.

A quick search right now shows any version claiming to be "Wise Maple" at ~$32, plus extra if you want it any sooner than August, if the vendor actually has it. I think the markup and 10-day delivery from bg is still good value, plus in this case it's an apples-apples comparison of the two products and service provided. 

mnem
 

[mansaxel]

philosophical argument: fuses exist to be replaced!

Functionally, by the silicon they're in series with.

[bd139]

philosophical argument: fuses exist to be replaced!

Functionally, by the silicon they're in series with.

Indeed. Although it’s perfectly possible to design silicon circuits that don’t explode first if you know what you’re doing. But the BOM cost is always higher. So instead we get the fuse, which is about as useful as a crash barrier made of bananas for protecting the device. But your house won’t burn down so they won’t get sued.

[bd139]

So I’ve been dredging eBay for something to play with and there is absolutely fuck all on there at the moment 

[AVGresponding]

Challenge accepted

[AVGresponding]

It's not easy to post from my shitty J6 but here's a few:

https://www.ebay.co.uk/itm/HP-3582A-Spectrum-Analyzer-/294239298862

https://www.ebay.co.uk/itm/HP-5334A-Frequency-Counter-Hewlett-Packard-/114859062183

https://www.ebay.co.uk/itm/Lloyd-Instruments-MPM-1015-Three-Phase-Inverter-/373624969047

https://www.ebay.co.uk/itm/HP-Hewlett-Packard-54520A-500-MHz-Digital-Oscilloscope-1GS-s-500MSa-s-/274835321193

https://www.ebay.co.uk/itm/TEKTRONIX-2440-500MS-S-DIGITAL-OSCILLOSCOPE-/324689570363

https://www.ebay.co.uk/itm/Hewlett-Packard-HP-11C-Programmable-Scientific-Calculator-with-Manual-/284341718967


One of my saved sellers seems to have acquired a large SK lot, it's in the US unfortunately:

https://ebay.co.uk/usr/the*treasure*trove*

[bd139]

Thank you for that. 54520a added to watch list 

[mnementh]

One of my saved sellers seems to have acquired a large SK lot, it's in the US unfortunately:

https://www.ebay.co.uk/usr/the*treasure*trove*

mnem

[Specmaster]

It's not easy to post from my shitty J6 but here's a few:

https://www.ebay.co.uk/itm/HP-3582A-Spectrum-Analyzer-/294239298862

https://www.ebay.co.uk/itm/HP-5334A-Frequency-Counter-Hewlett-Packard-/114859062183

https://www.ebay.co.uk/itm/Lloyd-Instruments-MPM-1015-Three-Phase-Inverter-/373624969047

https://www.ebay.co.uk/itm/HP-Hewlett-Packard-54520A-500-MHz-Digital-Oscilloscope-1GS-s-500MSa-s-/274835321193

https://www.ebay.co.uk/itm/TEKTRONIX-2440-500MS-S-DIGITAL-OSCILLOSCOPE-/324689570363

https://www.ebay.co.uk/itm/Hewlett-Packard-HP-11C-Programmable-Scientific-Calculator-with-Manual-/284341718967


One of my saved sellers seems to have acquired a large SK lot, it's in the US unfortunately:


[url=https://ebay.co.uk/usr/the]https://ebay.co.uk/usr/the*treasure*trove*[/url]
[/b][/color]

If that 2440 was working as claimed, then why the feck wouldn't they photograph it working???

[tggzzz]

Thank you for that. 54520a added to watch list 

Same seller also has a 1.5GHz probe, but it is a bit expensive: https://www.ebay.co.uk/itm/274825509075

I have three of them, so don't need more. They are my favourite probe - but I can't afford FET differential probes