Wind/diesel installation....

[frotter]

............I know Speccybloke does most of it ...............

Yeah well thats what HE would like to think.....
S'true Speccybloke has come to the fore in a big way recently. Various reasons for this -

1 He has recently become an inmate (lodger) at Frot Towers so he doesnt have to drag himself across Devon to interfere....
2 I cant keep him away from the equipment - Man must tinker...
3 I happily hand over fiddly wiring tasks cos he is so darn NEAT just like a real Alec Trician. (git)
4 He is stupidly clever at leccytroniks (wotever that is) Me - relays, warning lamps, switches, solenoids, ammeters. (dumbo).
5 ITS ALL HIS FAULT ANYWAY AS I WAS ORIGINALLY GOING TO PUT A W*NDSAVE TEAPOT ON MY CHIMBLEY AND HE TOLD ME I MUSTNT!!!

The mobility connection is because one part of my 'portfolio career' (ahem) has been to occasionally hang around in the workshop of a local Disability Centre where Speccybloke is Chief Engineer. Just like Chief O'Brien off of Star Trek - but less Irish. And shorter. The salvaged/scrap stuff that passes through that place is truly tinkerers porn..... We 'liberate' anything that looks interesting from the skip 

Stoveboy is in the wings but the current (ooh a sort of cr*p pun, only less funny) tasks mostly involve sparky things and he isnt the same sort of techhead like wot me an SB are. He likes guitars and having a rest. Also it is dark in t'evenings at the mo so not good for diggin holes in soft shoes. I expect he will on it over the weekend - weather and daytime sleeping permitting.....   

Er....

24v Alternator imbalance protection? Yep, thought of that. (The truck alternators concept was my idea as it happens.)
As it transpires it wont be needed. As next updates might illustrate.......

Laters doods..........

[frotter]

OK sooooo..... Weve got our 24v alts wired up, excitation circuits, ammeters and warning lamps in place. All set for trial run....
Wiring a bit temporary in nature (ahem) but i'm sure everything will be fiiiine!




On staring our wee enjin, one alternator self excited before the circuit was switched on (shouldnt be able to...) and the other briefly showed some life on turning on its ignition circuit and then promptly went off and seemed to blow the warning lamp...! This was quite late on Sunday night so we stopped it all and hung our heads dejectedly as we locked Chernobyl up for the night....... 
SpeccyOne reckoned the field diodes or regulators may have become a bit 'tired' in some way. I made an executive decision that the gay regulators were going in the bin.





Right i'll just bosh these wires straight to the brushes.....  External excitation anyone....? (i know Magical KEN has played with this..)





I did that with both b*ggers and then needed a variable power supply to excite the lektrons. I found two!




The train controller is weedy compared to the other power supply so the best balanced output we could get was........



About 20 amps from each alt. Ok but not great.
Sooooo, i thinks - wot about rejigging everything and trying to push the alt output to 48v? (both units). With enough excitation input.......

Next time then.......

 

[Antman]

On staring our wee enjin, one alternator self excited before the circuit was switched on (shouldnt be able to...) and the other briefly showed some life on turning on its ignition circuit and then promptly went off and seemed to blow the warning lamp...!
....
SpeccyOne reckoned the field diodes or regulators may have become a bit 'tired' in some way. I made an executive decision that the gay regulators were going in the bin.

Hi Frot

Most alternators will self-excite, given enough rpm, due to the residual magnetism in the rotor. This probably explains why one cut-in unaided.

I have only had experience of 12V alternators but I assume the theory is the same....

The diodes used have a very low reverse blocking voltage Vrrm as low as 18-20V. This is why people used to wonder why their alternators had mysteriously gone faulty just after charging the flat battery from an old fashioned charger (selenium rectifier type usually) without disconnecting the battery first. People often assumed that the alternator was the reason the battery failed whereas in many cases it was only the battery dying until the charger was wacked across overnight!

What happened was that any spike on the mains supply could cause a correspondingly lower 'blip' on the charger output - which in turn blew the field or stator diodes.  Connecting jump leads with the good engine running can have a similar effect; arcy sparky spiky wiky, pop, Ooops 
Hence charging the battery on the vehicle should only ever be carried out using a charger with a regulated output i.e. limited to 14.2V max.

However the point of this wittering-on is that you are creating a 48V system by series connecting two 24V alternators - the normal designed maximum voltage of which would be around 28-30V. Therefore the diodes may only have a Vrrm of about 40-44V for example.
Soooo  by series connecting another alternator, the reverse stack voltage seen by the diodes thropugh the load becomes exceeded on a given alternator.

This is also the likely reason why the 24V 'ignition' lamp blew, as it would have momentarily seen 40V+ (via the rotor winding) as the first alternator cut-in - even though the second IGN switch was still off.

I hope this makes sense.... it may help to understand how to resolve the problem.


Maybe regulator/diode stacks intended for marine applications would work as they are presumably designed to withstand the series voltage.

Regards

Antman

[frotter]

Ah - no at this point the two alts were seperately charging half the battery bank each. 24volts apiece. Obviously the outputs needed to be balanced or our cell volts would have been all over the place...
Since last post we have rewired the whole caboodle so the alts are in parallel and are exciting the buggers to give 48volts each. We took various readings from Speccyblokes power supply and found that at its maximum output (2.5amps at 17volts) we are getting 40 amps at around 50 volts. We have temperature probes installed to monitor possible melting but so far only managed to cook them up to around 45-50 degrees C. 
Speccy Wan is at this moment working out a circuit to build two controllable power supplies to give us more excitation overhead - and see if we can get 100 amps between the two. Thats our target.
The alts we have appear to be completely standard Lucas A127 type alternator. The only thing that makes it 24v is obviously the regulation. I could have saved myself £150 odd quid by getting a couple of cheapos off of old Ford Mundanos or summat down the scrappy! 
Still - roll on tomorrow, maybe have more to report......

 
 

[frotter]

Did i say 100 amps...? mustve been dreaming....

To excite our (now 48volt  ) alts Speccybloke has designed a double power supply circuit with adjustable output so we can muck about with it.
here he is in his fume laden sparky den of doom...
He has ABSOLUTELY no idea what he is diong, bless him.



Testing, testing. Go ON - turn it up to 11!




Yikes! straight to brown alert on No 1 Alternator!




With both cranked up to max and Kubota slogging away at full bollix we can achieve summat like this..



The ammeters are about 5 amps optimistic...
We are finding that the maximum sensible (true,measured) output is about 65 amps (about 3.2KW) as if its cranked right up when the electric cooling fan comes on the engine can be dragged slowly down out of its power band - doesnt always recover on fan switching off.
We are having to run about 5 hours or so to meet our usual 15 - 17kwh per day needs. Blimey! Need some wind!
It really seems to drink the lard too! Having trouble finding the time to melt, filter, decant etc enough of the filthy brown gold. Also Chernobyl gets SUPER TOASTY inside! We need to be taking that heat away into Frot Towers.........

XX


PS - interesting observation. When shutting down/flushing lard out of system on diesel, if the alts are not turned down the revs die right off. Diesel can only sustain about 55 amps flat out. Lard 65 amps. 
Lard 1   -  Diesel 0

 

[frotter]

MIND THE GAP!
Sorry for long silence.... had a fair amount of testing/monitoring/teething problems to attend to.
One of SpeciWans super stairlift brackets gave way so i had to 'repair' it with a neat bit of Dexion.........




We also were finding the alternators getting a bit hot - mind you, i dont think we should be surprised - pulling a constant 2KW out of a normal sized car alternator is pretty impressive i reckon!
So - extremely neat holes were chewed in the wall.....





And flexi ducting introduced to draw nice chilly air straight into the units....




Seems to work- under full load the temp probes on the outside of the cases show 60 or so degrees.

Sadly, half of SpeciWans' splendid excitation supply gave up (again). So i have been bothering RS again for more little bags of silicon spiders for him to play about with.......

Blimmin' 'eck!!

XX

[frotter]

Yikes!
Quite glad the wind has eased off...... we were all a bit nervous to be anywhere near the 3metre fibreglass 'deathbringers' flailing around dementedly......
The constant high output actually melted the solder inside our nice (Chinese, obviously) ammeter - i had to temporarily bypass it and fix the b*gger.



Scary having the turbine brake engaged but still seeing the blades spinning round like mad!      I bet that comedy rubber chinese flex was heating up underground......
At one point the needle was bending up against the upper stop constantly. I immediately donned the army surplus ARP wardens hat and scurried away quickly....
MEANWHILE..... we are still on autorunning - the inverter deciding when to run the genny etc. Sadly SpeciWan's newly beefed up excitation supply failed miserably AGAIN! (dont know why i bother....    )
I had to take matters into my own hands and revert to Frotbodge 23c to excite the alternators. This is how i was going to do it originally, being bereft of lektronikal knowledge.
My plan involved one of these........



Manky but working ancient mobility scooter. (one of our Frot Towers Garden Racing Team fleet...)
These things run on 24volts and have a nice robust motor controller capaple of putting out 30-40 amps+ constantly. Plenty for pushing into alternators.........
A Curtis motor controller - mmmmmm.....
SpeciWan has (as is his wont..) slightly modified this one, removing the changeover relays which give reverse. We only really want our elctrons to go FORWARD!



This unit works really well. We have taken 24volts from the centre of the batts to power it. It only fires up on the gen 'run' signal via a relay (i luv relays, me...) and controls both alternators in parallel via one control knob. We can adjust the output really nicely and currently use the setup in 'Stealth Mode' (Copyright World of Ken 2007). This gives out 55-60 amps (3kw) at around half revs or less. No tacho so just guessing. Probably 1200-1500 revs.
The current into the alternator rotors is about 2 - 2.5 amps each unit. The trusty Curtis controller hardly notices it - result! 

KK - more next time - if anyone can still be ars*d!

XX
 

[room101]

Its the highlight of my day when i see one of your posts, keep it up....

[KenB]

Nice One Frot!

Despite your self-claimed lack of lecky knowledge your doing a darn fine job down there in windy Devon.

Foolishly, I studied, and got a degree in leckytronics, which makes me least qualified to tackle these sort of jobs.  Actually - it's cos I'm  morbidly scared of electrons, especially when the all gang up on you, and rush out all at once.

I'm sure fitting a blower fan on that nice 60V  4.8kW shunt motor I lent you would have been quicker and easier - but who am I to judge, having spent 3 weeks messing about with wood gas pick-ups and other stuff.

Mr. Lister and the twins say "Hi" BTW.



Ken

[Panda_Badger]

Always a pleasure to read a frott posting. Looks like you're having fun as usual, how are the PVs fairing in this luvly Autumnal weather?

Keep up the good frotting.

Pete.

[frotter]

Heh - thx for your comments all..!
PV panels trying bravely is the best that can be said. On the rare occasion of a sunny spell they shove out around 10-12 amps MAX. (summer we have seen 21 amps in the brightest light..) Amazing what a few less degrees of elevation can do.... They seem to be survivng the buffeting so far.
Ken - you may be right about that giant lump of metal motor you loaned me - i was already committed to alternators by then though. Thing is though, with the knowledge we have picked up from this anyone who wants to charge batteries would have a struggle to find something as small and easily managed to get 2kw out of. Thats a constant 2kw - not to be sniffed at by anyones hooter methinks. I would really like it if someone used our experiences to build a super economy setup with a £10 alternator from a scrappy and a scavenged diesel lawnmower engine. Come on someone! I know yer out there!!!

Wind turtle all confused tonight - blustering about all over the shop. We should have lots of different words for different winds. You know like fat blokes do for cake and that.

X

[martin]

how are your groundscrew thingummyjigglers faring after a bit of a blow?

[frotter]

Well they seem distinctly 'not bovvered'. The tops of them do move a little if you kick them as i guess the upper part of the earth compacts around them. Apart from that they dont seem to have budged at all. To be honest i think now i am more concerned about pole and blades. I want to get the tower up and check clamps/bolts etc before too much more winter.....

X

[martin]

excellent! - I'm hoping to shortly get one of the new 300w jobbies flying, and I've got some left over.........what with that, and the fact that I've just heard that we are to expect a carrier to arrive tomorrow bearing large wooden packing cases (plural) - containing Listery/Pettery engines, you may have to look to your laurels............

[frotter]

Well they were certainly easy to fit. No messing with concrete - just a spanner and sledgehammer!