load bank puzzle...

[John Larkin]

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

 

[Clive Arthur]

On 17/03/2023 15:21, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

<snip>

Plenty of power rheostats available. eBay has loads, many new.
Inductance is a separate matter (though they will have some of course -
get tubular rheostats and bung a ferrite rod down the centre?).

--
Cheers
Clive

 

[Jan Panteltje]

On a sunny day (Fri, 17 Mar 2023 08:21:23 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<u6091ide59fffa8gafp93ipmmejp424r5j@4ax.com>:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

Yes why not..
\'SSR\' == solid state rectifier ? you mean relay? You get AC as input right?
oh wait you mean sold state relay....
googling SSR gives among many things Wikipedia with \"Soviet Socialist Republic\"

But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

We use rectangles as resistor symbol here

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

My setup:
https://panteltje.nl/pub/power_resistors_IMG_6291.JPG
uses test leads with alligator clips to switch configuration.

So as to Soviet Socialist Republic
Here a very funny thing happened in politics
We just had elections, and a new party, BBB (translated: farmers people movement)
wiped out all parties going from zero to more than the biggest ones.
Protest against all the CO2 idiots who want to close farms because cows make CO2.
I voted for them too
We need farmers and their produce.
We will see where it goes now...

 

[John Larkin]

On Fri, 17 Mar 2023 16:32:56 +0000, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

On 17/03/2023 15:21, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

snip

Plenty of power rheostats available. eBay has loads, many new.
Inductance is a separate matter (though they will have some of course -
get tubular rheostats and bung a ferrite rod down the centre?).

We want 8 channels on a PC board, programmable resistance.

 

[whit3rd]

On Friday, March 17, 2023 at 8:21:37 AM UTC-7, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts ...

So far, a Variac and big resistor on the output is a possibility.
Or, a few paint cans full of oil, with rotary switch and immersed lower-watt
resistors (Cantenna style), could work.

But, \'load\' for even just a battery test can be anything from 1 ohm to hundreds,
just for the batteries in my household; the only easy way to make the load
you want, is to specify it first, then build one. That means the \'load board\' is
a connector plenum, and the loads would be plugins to that, plucked from
a bucket of prebuilt options.

Eight-channel is easy: design one, build eight, and strap \'em together.

 

[Lasse Langwadt Christensen]

fredag den 17. marts 2023 kl. 17.58.53 UTC+1 skrev John Larkin:

On Fri, 17 Mar 2023 16:32:56 +0000, Clive Arthur
cl...@nowaytoday.co.uk> wrote:

On 17/03/2023 15:21, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

snip

Plenty of power rheostats available. eBay has loads, many new.
Inductance is a separate matter (though they will have some of course -
get tubular rheostats and bung a ferrite rod down the centre?).
We want 8 channels on a PC board, programmable resistance.

8*10W is going to require quite a bit of cooling

https://www.pickeringtest.com/en-dk/product/load-resistor-module-40r-to-295r-011

 

[John Larkin]

On Fri, 17 Mar 2023 16:40:09 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Fri, 17 Mar 2023 08:21:23 -0700) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
u6091ide59fffa8gafp93ipmmejp424r5j@4ax.com>:


I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

Yes why not..
\'SSR\' == solid state rectifier ? you mean relay? You get AC as input right?
oh wait you mean sold state relay....

Yes.

googling SSR gives among many things Wikipedia with \"Soviet Socialist Republic\"


But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

We use rectangles as resistor symbol here

Quaint olde world customs.

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

My setup:
https://panteltje.nl/pub/power_resistors_IMG_6291.JPG
uses test leads with alligator clips to switch configuration.

We have a couple of Kikusui benchtop electronic load boxes, which are
handy. They can do square wave loads, handy for checking power supply
dynamics.

I want programmable 0 to 1 zillon ohms, isolated, ac/dc, 10 or 20
watts, metered, overload protected, 8 loads per board, maybe 4 square
inches per channel.

I was wondering if anyone had cute ideas. I considered PWM-ing a big
resistor, but that has complications.

So as to Soviet Socialist Republic
Here a very funny thing happened in politics
We just had elections, and a new party, BBB (translated: farmers people movement)
wiped out all parties going from zero to more than the biggest ones.
Protest against all the CO2 idiots who want to close farms because cows make CO2.
I voted for them too
We need farmers and their produce.

Most people think eating is good.

We will see where it goes now...

People will surely get tired of crazy prices and blackouts and food
shortages and waiting hours to recharge their cars.

 

[John Larkin]

On Fri, 17 Mar 2023 10:17:30 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

fredag den 17. marts 2023 kl. 17.58.53 UTC+1 skrev John Larkin:
On Fri, 17 Mar 2023 16:32:56 +0000, Clive Arthur
cl...@nowaytoday.co.uk> wrote:

On 17/03/2023 15:21, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

snip

Plenty of power rheostats available. eBay has loads, many new.
Inductance is a separate matter (though they will have some of course -
get tubular rheostats and bung a ferrite rod down the centre?).
We want 8 channels on a PC board, programmable resistance.

8*10W is going to require quite a bit of cooling

https://www.pickeringtest.com/en-dk/product/load-resistor-module-40r-to-295r-011

I was thinking of kink-leading some axial wirewound resisors like they
do. We\'ll have a lot of air flow so the cooling should be OK.
Wirewound resistors can get very hot.

 

[John Larkin]

On Fri, 17 Mar 2023 10:07:32 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Friday, March 17, 2023 at 8:21:37?AM UTC-7, John Larkin wrote:
I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts ...

So far, a Variac and big resistor on the output is a possibility.

Not on a PC board. Variacs are AC devices anyhow. Big and expensive.

Or, a few paint cans full of oil, with rotary switch and immersed lower-watt
resistors (Cantenna style), could work.

But, \'load\' for even just a battery test can be anything from 1 ohm to hundreds,
just for the batteries in my household; the only easy way to make the load
you want, is to specify it first, then build one. That means the \'load board\' is
a connector plenum, and the loads would be plugins to that, plucked from
a bucket of prebuilt options.

Eight-channel is easy: design one, build eight, and strap \'em together.

This will be a product, a plugin board to a rackmount instrument.

 

[Martin Rid]

John Larkin <jlarkin@highlandSNIPMEtechnology.com> Wrote in message:r

I\'ve been asked to design an 8-channel dummy load board. It\'s not verychallenging but somebody\'s got to do it. It will be used to simulatesmall loads like solenoids or relays or torque motors. It needs someinductance too, because the drivers often PWM. Maybe 10 or so wattsper channel.I could do this electronically, but it would a lot easier and morerugged if I use wirewound resistors. I was thinking of making aconductance DAC, namely resistors R 2R 4R etc switched in parallelacross the inputs with an SSR per resistor. But there is a history of clever load banks. When I was an EE studentat Tulane, two semisters of Electrical Machinery (with lab) wasmandatory. It was a pain but I learned a lot. We had a big load bankin the machinery lab, a string of giant series resistors with a3-position knife switch at each node. That made me think about usingseries-parallel combinations to hit some target value.https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1The upper pic is the ancient Tulane load bank as I remember it.I was thinking about the lower circuit for my gadget. I could usewirewould resistors and kink the leads to space them maybe 3/4 inchabove my PCB, in the air st
ream. The higher value resistors might be2512 surface mounts.I think there is a tool to bend and kink resistor leads. Or we couldsend a bunch out to a service maybe.

Board assembly houses should have the lead crimpers. I believe it
only works with tape reel packaging. Could be wrong but check
with the vendor.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html

 

[legg]

On Fri, 17 Mar 2023 08:21:23 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

Active I=kV with a delay would give you an inductance.

Does the driver really care?

Where\'d the word \'dummy\' originate in the spec? If it reflects
the attitude of the buyer, I\'d say \'No Bid\'. I\'ve had it with
idiots like that.

RL

 

[John Larkin]

On Fri, 17 Mar 2023 17:14:59 -0400, legg <legg@nospam.magma.ca> wrote:

On Fri, 17 Mar 2023 08:21:23 -0700, John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote:


I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.




Active I=kV with a delay would give you an inductance.

A real inductor stores energy, which a synthesized inductor usually
doesn\'t.

Stored energy pumps current into flyback diodes or equivalent.

Does the driver really care?

It certainly might.

Where\'d the word \'dummy\' originate in the spec? If it reflects
the attitude of the buyer, I\'d say \'No Bid\'. I\'ve had it with
idiots like that.

Oh, they are just a biggish aerospace company.

No bid? Is that a good business model?

RL

https://en.wikipedia.org/wiki/Dummy_load

 

[Lasse Langwadt Christensen]

fredag den 17. marts 2023 kl. 22.13.01 UTC+1 skrev legg:

On Fri, 17 Mar 2023 08:21:23 -0700, John Larkin
jla...@highlandSNIPMEtechnology.com> wrote:


I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.



Active I=kV with a delay would give you an inductance.

sure it can slow the current rise like an inductor but it won\'t keep the current flowing after turnoff

 

[Tabby]

On Friday, 17 March 2023 at 16:40:16 UTC, Jan Panteltje wrote:

On a sunny day (Fri, 17 Mar 2023 08:21:23 -0700) it happened John Larkin
jla...@highlandSNIPMEtechnology.com> wrote in
u6091ide59fffa8ga...@4ax.com>:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.
Yes why not..
\'SSR\' == solid state rectifier ? you mean relay? You get AC as input right?
oh wait you mean sold state relay....
googling SSR gives among many things Wikipedia with \"Soviet Socialist Republic\"
But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1
We use rectangles as resistor symbol here
The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.
My setup:
https://panteltje.nl/pub/power_resistors_IMG_6291.JPG
uses test leads with alligator clips to switch configuration.

clever idea using the user\'s arse as a power monitor.

 

[Tabby]

On Friday, 17 March 2023 at 21:42:04 UTC, John Larkin wrote:

> No bid? Is that a good business model?

sometimes it is.

 

[John S]

On 3/17/2023 11:40 AM, Jan Panteltje wrote:

On a sunny day (Fri, 17 Mar 2023 08:21:23 -0700) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
u6091ide59fffa8gafp93ipmmejp424r5j@4ax.com>:


I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

Yes why not..
\'SSR\' == solid state rectifier ? you mean relay? You get AC as input right?
oh wait you mean sold state relay....
googling SSR gives among many things Wikipedia with \"Soviet Socialist Republic\"


But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

We use rectangles as resistor symbol here



The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

My setup:
https://panteltje.nl/pub/power_resistors_IMG_6291.JPG
uses test leads with alligator clips to switch configuration.

So as to Soviet Socialist Republic
Here a very funny thing happened in politics
We just had elections, and a new party, BBB (translated: farmers people movement)
wiped out all parties going from zero to more than the biggest ones.
Protest against all the CO2 idiots who want to close farms because cows make CO2.
I voted for them too
We need farmers and their produce.
We will see where it goes now...

I thought cows made methane which is a worse greenhouse gas than CO2.

--
Dogs make me happy. Humans make my head hurt.

 

[Anthony William Sloman]

On Saturday, March 18, 2023 at 3:33:04 AM UTC+11, Clive Arthur wrote:

On 17/03/2023 15:21, John Larkin wrote:

I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.
snip

Plenty of power rheostats available. eBay has loads, many new.
Inductance is a separate matter (though they will have some of course -
get tubular rheostats and bung a ferrite rod down the centre?).

Not good idea. Rheostats get hot. and ferrite rods tend to have a low Curie temperature.

Manganese-zinc ferrites have Curie temperatures from 120°C – 300°C.

--
Bill Sloman, Sydney

 

[Sylvia Else]

On 18-Mar-23 8:14 am, legg wrote:

Where\'d the word \'dummy\' originate in the spec? If it reflects
the attitude of the buyer, I\'d say \'No Bid\'. I\'ve had it with
idiots like that.

\"Dummy load\" seems a terminology common enough not to suggest anything
about the buyer.

Sylvia.

 

[Jan Panteltje]

On a sunny day (Fri, 17 Mar 2023 21:36:10 -0500) it happened John S
<Sophi.2@invalid.org> wrote in <tv3831$20nan$1@dont-email.me>:

On 3/17/2023 11:40 AM, Jan Panteltje wrote:
So as to Soviet Socialist Republic
Here a very funny thing happened in politics
We just had elections, and a new party, BBB (translated: farmers people movement)
wiped out all parties going from zero to more than the biggest ones.
Protest against all the CO2 idiots who want to close farms because cows make CO2.
I voted for them too
We need farmers and their produce.
We will see where it goes now...




I thought cows made methane which is a worse greenhouse gas than CO2.

Yea, those CO2 or climate fear mongering idiots are against everything
https://pubmed.ncbi.nlm.nih.gov/8675759/

>Dogs make me happy. Humans make my head hurt.

We should kill all dogs? those make CO2 too.
and dogs shit everywhere.

It is all about selling snake oil.
What needs to happen is build more nuclear power plants so we can create our own environment to
keep inhabiting our locations.
Heating, aircos, shelters..
But the brainless a-technical paranoid greta thunberg clueless crowd is the advertising agent for climate crap sellers.

Climate change is caused by earth orbit variations:
http://old.world-mysteries.com/alignments/mpl_al3b.htm

 

[Jan Panteltje]

On a sunny day (Fri, 17 Mar 2023 10:22:33 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<5l791i1hev1qsuei98p7t83mprc4881jhk@4ax.com>:

On Fri, 17 Mar 2023 16:40:09 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Fri, 17 Mar 2023 08:21:23 -0700) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
u6091ide59fffa8gafp93ipmmejp424r5j@4ax.com>:


I\'ve been asked to design an 8-channel dummy load board. It\'s not very
challenging but somebody\'s got to do it. It will be used to simulate
small loads like solenoids or relays or torque motors. It needs some
inductance too, because the drivers often PWM. Maybe 10 or so watts
per channel.

I could do this electronically, but it would a lot easier and more
rugged if I use wirewound resistors. I was thinking of making a
conductance DAC, namely resistors R 2R 4R etc switched in parallel
across the inputs with an SSR per resistor.

Yes why not..
\'SSR\' == solid state rectifier ? you mean relay? You get AC as input right?
oh wait you mean sold state relay....

Yes.

googling SSR gives among many things Wikipedia with \"Soviet Socialist Republic\"


But there is a history of clever load banks. When I was an EE student
at Tulane, two semisters of Electrical Machinery (with lab) was
mandatory. It was a pain but I learned a lot. We had a big load bank
in the machinery lab, a string of giant series resistors with a
3-position knife switch at each node. That made me think about using
series-parallel combinations to hit some target value.

https://www.dropbox.com/s/x3e7xxi13n6wd1o/Load_Banks_1.jpg?raw=1

We use rectangles as resistor symbol here

Quaint olde world customs.




The upper pic is the ancient Tulane load bank as I remember it.

I was thinking about the lower circuit for my gadget. I could use
wirewould resistors and kink the leads to space them maybe 3/4 inch
above my PCB, in the air stream. The higher value resistors might be
2512 surface mounts.

I think there is a tool to bend and kink resistor leads. Or we could
send a bunch out to a service maybe.

My setup:
https://panteltje.nl/pub/power_resistors_IMG_6291.JPG
uses test leads with alligator clips to switch configuration.

We have a couple of Kikusui benchtop electronic load boxes, which are
handy. They can do square wave loads, handy for checking power supply
dynamics.

I want programmable 0 to 1 zillon ohms, isolated, ac/dc, 10 or 20
watts, metered, overload protected, 8 loads per board, maybe 4 square
inches per channel.

I was wondering if anyone had cute ideas. I considered PWM-ing a big
resistor, but that has complications.


So as to Soviet Socialist Republic
Here a very funny thing happened in politics
We just had elections, and a new party, BBB (translated: farmers people movement)
wiped out all parties going from zero to more than the biggest ones.
Protest against all the CO2 idiots who want to close farms because cows make CO2.
I voted for them too
We need farmers and their produce.

Most people think eating is good.

We will see where it goes now...



People will surely get tired of crazy prices and blackouts and food
shortages and waiting hours to recharge their cars.

I did a switched inductor thing many many years ago,
it was for tuning and used relays IIRC (up to a few hundred kHz).
I see electronics to simulate inductors as a possibility.
But what sort of users need this?
Normally you would test on the real thing
any unexpected things could exist in a real system,
parasitic capacitances, lead resistance and inductances,
unexpected couplings.. what not.
Nothing like a real test.

Bridge rectifier with a power MOSFET in it for AC load?
Gives all sort of problems too...