Farm Engineering

[sjt01]

It controls an inverter which takes 400Vdc in and produces 3-phase AC out. Originally it will be used for interfacing 400V worth of solar panels with a 110Vac grid. We're also building a low voltage version where to drive a 48V AC motor for an electric vehicle application. This card is the brain of the outfit.

Looking forward to the pictures of the build of the EV

 

[TechWise]

Looking forward to the pictures of the build of the EV

It's not quite what you might think. We're entering a competition where you basically make a small bogey with a wind turbine sticking out the back and whoever drives the fastest INTO the wind wins.

Here's a couple of all-mechanical solutions. We'll be one of the first teams to try and go all electric. We take the 3-phase AC from the turbine, convert it to DC and push it into a capacitor. The power converter draws just enough current out of the turbine to keep it spinning at its optimum speed for maximum power extraction from the wind. From the DC capacitor, we have a second converter which converts the DC back to 3-phase AC to drive a motor for the wheels. If the DC voltage starts to drop, it knows it's pulling more power out than the first converter is pushing in so it backs off. If the DC link voltage starts to rise, it knows more power is being pushed in by the wind than it's pulling out so it speeds the car up a bit.

 

[sjt01]

It's not quite what you might think. We're entering a competition where you basically make a small bogey with a wind turbine sticking out the back and whoever drives the fastest INTO the wind wins.
View attachment 862945
Here's a couple of all-mechanical solutions. We'll be one of the first teams to try and go all electric. We take the 3-phase AC from the turbine, convert it to DC and push it into a capacitor. The power converter draws just enough current out of the turbine to keep it spinning at its optimum speed for maximum power extraction from the wind. From the DC capacitor, we have a second converter which converts the DC back to 3-phase AC to drive a motor for the wheels. If the DC voltage starts to drop, it knows it's pulling more power out than the first converter is pushing in so it backs off. If the DC link voltage starts to rise, it knows more power is being pushed in by the wind than it's pulling out so it speeds the car up a bit.

What a fantastic challenge. If I had time on my hands I would have a go. Supercapacitors would seem the way to go as your storage is all short term. What sort of power levels are you expecting from the turbine? Is this car alternator AC, or are you going more sophisticated?

 

[sjt01]

It's not quite what you might think. We're entering a competition where you basically make a small bogey with a wind turbine sticking out the back and whoever drives the fastest INTO the wind wins.
View attachment 862945
Here's a couple of all-mechanical solutions. We'll be one of the first teams to try and go all electric. We take the 3-phase AC from the turbine, convert it to DC and push it into a capacitor. The power converter draws just enough current out of the turbine to keep it spinning at its optimum speed for maximum power extraction from the wind. From the DC capacitor, we have a second converter which converts the DC back to 3-phase AC to drive a motor for the wheels. If the DC voltage starts to drop, it knows it's pulling more power out than the first converter is pushing in so it backs off. If the DC link voltage starts to rise, it knows more power is being pushed in by the wind than it's pulling out so it speeds the car up a bit.

I mentioned this project to an engineer who worked on Dale Vince's Nemesis car (Ecotricity), and he said
"I like, that's a great competition. I remember reading something similar on a boat, apparently it could sail directly into the wind:

Can't find the references but I seem to remember a hydraulic link between turbine and prop? However I might be confusing things.
Some form of variable load system seems a good idea to keep the turbine near the betz limit (59.6%), so all electric would be my first thought, despite probably losing at least 20% of the energy in the mechanical-electrical to electrical-mechanical conversion. Whatever 'efficient' solution is found it is going to hit a speed-energy wall fairly quickly."

 

[TechWise]

I mentioned this project to an engineer who worked on Dale Vince's Nemesis car (Ecotricity), and he said
"I like, that's a great competition. I remember reading something similar on a boat, apparently it could sail directly into the wind:
View attachment 863021
Can't find the references but I seem to remember a hydraulic link between turbine and prop? However I might be confusing things.
Some form of variable load system seems a good idea to keep the turbine near the betz limit (59.6%), so all electric would be my first thought, despite probably losing at least 20% of the energy in the mechanical-electrical to electrical-mechanical conversion. Whatever 'efficient' solution is found it is going to hit a speed-energy wall fairly quickly."

I haven't seen a waterborne version before but it's a similar idea. Most teams go with a mechanical solution either with a clutch and gearbox or a CVT. One of the biggest issues is that if you try to transmit the power down the mast with a shaft, it's easier for the turbine to turn round and round at the top of the mast rather than the turbine staying put and forcing the shaft to spin under it. You need quite a hefty yaw control system to stop that happening.
With the electrical version, that problem doesn't exist because the generator is contained at the top of the mast. We have a couple of aerospace guys looking at the blade shape and deterimining the maximum power point. I rely on them coming up with a number then I program the generator controller to always extract the perfect amount of torque to keep the turbine at that speed.
Not a particularly useful vehicle but there's some serious engineering involved! All good fun too and we get a wee trip to the Netherlands for the race.

 

[Vincent]

Making a tail board for the dump trailer .

 

[Vincent]

Got it fitted , now to sort a closing latch.

 

[Two Tone]

View attachment 864219View attachment 864220View attachment 864221Got it fitted , now to sort a closing latch.

Apparently, you can also paint it on this thread without getting the bollocking you would if you put it on the quick fix, bodges and creations thread!

Well done, nice job.

 

[Vincent]

Hoping to get the whole trailer shot blasted and resprayed when things get back to normal.

 

[fermerboy]

Something entirely different to resurrect the thread.... A different sort of engineering.

Been working on a control circuit board and started to get errors saying my computer couldn't connect to the board. Happened to touch the processor and discovered it was red hot. Game over for the processor chip but not for the board. The processor is the black chip in the middle, measures about 20mm square. Not much to look at but it has 377 little tiny connections underneath!
View attachment 862779
The procedure to remove is to soak the whole thing in flux, preheat from below with a heated table and then use a hot air gun from above the melt the solder and ease the chip up. Hey presto, off she comes! Then we take a soldering iron, loads more flux and a copper desoldering wick and draw it across all the pads slowly and carefully to wick away remaining solder and leave only the pads on the ciruit board. A really good scrub with a rubbing alcohol and we're left with this - clean pads ready to receive the new chip.
View attachment 862780
The real concern is whether all of the pads have survived the process. Each one is about the size of a grain of sand so not easy to tell. Into the microscope!

View attachment 862781
If all of the pads are as intact as these four we're onto a winner.
View attachment 862782
Here we see that the blue "solder resist" coating has come away over a small area. Hopefully that won't cause an issue. The new chip has been ordered and will come looking like this, with all the little pads having a ball of solder attached. It gets placed on the circuit board and then the whole thing goes in the oven and if all goes well it melts down into place where the old one was.

Wow! Just Wow!!
So envious of your ability.

I can just about solder something on to a circuit board if its simple.
Had to learn to repair recifiers on my wind turbine, can replace thermistors, thyristor, and bridge rectifier now, and thought I was doing well.
Replaced the antenna on my Davis weather station too, but that was me at my limit, its just so small and fiddly.

 

[colhonk]

Nice to see that you have taken the time to grind the sharp edges and corners off on your brackets, finishes the job off

 

[Gerbert]

View attachment 864219View attachment 864220View attachment 864221Got it fitted , now to sort a closing latch.

Nice work, but won't it block like crazy? I have a trailer with same kind of gravity operated tailgate but the hinges are far more to the front, so it opens further.

 

[Vincent]

Only need a tail board for the odd run to the local quarry and the like, for most jobs it will be removed.

 

[Vincent]

Went for simple with the closing set up.

 

[simon-0116]

Did you get away with anything?

Cup of tea from customer whilst we was waiting to move door frame / stud wall

 

[Greenbeast]

I have no pictures or results to show but i just sold someone 65m of 5 core SWA this week, he'd been to pick up some large variacs and a transformer on the way, of course i was intrigued....

Turns out he has a hayter mower and a paddock, instead of buying and maintaining an old tractor he's fitted a 3 phase motor to it and wanted the cable to power the motor (from a leccy supply at the corner of the field) as he dragged it up and down the field....

 

[Zebbedee]

I have no pictures or results to show but i just sold someone 65m of 5 core SWA this week, he'd been to pick up some large variacs and a transformer on the way, of course i was intrigued....

Turns out he has a hayter mower and a paddock, instead of buying and maintaining an old tractor he's fitted a 3 phase motor to it and wanted the cable to power the motor (from a leccy supply at the corner of the field) as he dragged it up and down the field....

Bloody hell he is brave,,,,,,I borrowed my brothers electric hedge cutter once and managed to cut the cable 3 times in a couple hours work so would not relish the thought of a 3 phase lawn mower ??????

 

[jack_c]

Hope this is the appropriate thread for this,
Mole plough that I've been in the process of making for about 3 years.
Had a waterlogged area in a field so necessity forced completion along with a little more free time due to the current climate.
Few finishing touches to add to tidy it up but took it out for some field testing last night to ensure it worked OK.
Any suggestions before I clean if off for painting?

 

[Flat 10]

View attachment 866778
View attachment 866780
Hope this is the appropriate thread for this,
Mole plough that I've been in the process of making for about 3 years.
Had a waterlogged area in a field so necessity forced completion along with a little more free time due to the current climate.
Few finishing touches to add to tidy it up but took it out for some field testing last night to ensure it worked OK.
Any suggestions before I clean if off for painting?

Very smart and professional. i think its a bit too late for suggestions......

 

[spanners and hammers]

Something entirely different to resurrect the thread.... A different sort of engineering.

Been working on a control circuit board and started to get errors saying my computer couldn't connect to the board. Happened to touch the processor and discovered it was red hot. Game over for the processor chip but not for the board. The processor is the black chip in the middle, measures about 20mm square. Not much to look at but it has 377 little tiny connections underneath!
View attachment 862779
The procedure to remove is to soak the whole thing in flux, preheat from below with a heated table and then use a hot air gun from above the melt the solder and ease the chip up. Hey presto, off she comes! Then we take a soldering iron, loads more flux and a copper desoldering wick and draw it across all the pads slowly and carefully to wick away remaining solder and leave only the pads on the ciruit board. A really good scrub with a rubbing alcohol and we're left with this - clean pads ready to receive the new chip.
View attachment 862780
The real concern is whether all of the pads have survived the process. Each one is about the size of a grain of sand so not easy to tell. Into the microscope!

View attachment 862781
If all of the pads are as intact as these four we're onto a winner.
View attachment 862782
Here we see that the blue "solder resist" coating has come away over a small area. Hopefully that won't cause an issue. The new chip has been ordered and will come looking like this, with all the little pads having a ball of solder attached. It gets placed on the circuit board and then the whole thing goes in the oven and if all goes well it melts down into place where the old one was.

everyman to his own skill set very interesting ,,, i gess we wont be seeing much of you in the bodge thread