Barnaby the Vusky

[Uncle Henry]

Nice one, Famous Dave.

Can you answer me this, please : going on the premise that you can't get summat for nowt, does a 60 amp unit take more power to drive than a 40 amp one ? Ie, are you slowing your acceleration in exchange for "never-actually-gonna-need-it" higher alternator output ? If not, why does anybody ever bother with a lower output offering ?


UH

[John A. Ross]

Nice Job Dave

[Dave Lane]

[QUOTE=Uncle Henry;n12760]Nice one, Famous Dave.

Can you answer me this, please : going on the premise that you can't get summat for nowt, does a 60 amp unit take more power to drive than a 40 amp one ? Ie, are you slowing your acceleration in exchange for "never-actually-gonna-need-it" higher alternator output ? If not, why does anybody ever bother with a lower output offering ?

OK so it works like this , Normally the higher the output the bigger the alternator , so a 40A Denso has a 93mm stator , 60A has a 100mm stator , 120A has a 118mm stator - and so on .
Its to do with how much wire you can get into the stator slots ( smaller stator , smaller slots ) , manufacture limitations ( mass production ) and heat dissipation.
Manufacturers always use a single wire and around ten turns per slot , To get more Amps out requires fatter wire which just wont fit due to the stator slot size plus being fatter it wont bend well .
To overcome this you can use two thinner wires run in parallel but this results in less turns .
Running two ( or more ) in parallel is very difficult to do on a mass production line so they just go up an alternator size , bigger slots in the stator , more room for fatter wire and therefor more Amps out.
Because mine are hand wound I can fit two thinner wires in parallel ( two thinner ones with a greater cross sectional area than the one fat one ) although with less turns (because it wont fit )
Turns control the cut in speed , the less turns the higher the cut in . The absolute minimum for a road going car is 7 turns , any less and the cut in is way too high .
I can easy get 120A out of a tiny 93mm alternator such as this one by fitting just 4 turns and using three wires in parallel and 160A out of the 100mm ones ,using 3 turns and four wires in parallel . Problem is the cut in speed is ridiculous at around 5,000RPM engine speed , useless for a road car but great on a track or race car , NASCAR use these 160A ones for example .
Its all a question of balance really . driving an alternator at 60A would take more than 40A if on full load .
HOWEVER it only produces what the car needs so it wont effect that so if the Vusky only wants 10A then thats all it produces ,
Theres two reason for doing all this -
More Amps at a lower rotor speed so headlights , heater fan etc all on during tickover and the battery still copes and gets charged even then.
A 60A alternator under run is much less stressed and runs much cooler , less resistance and therefor less drag on the engine .
Run a 40A alternator at 40A all the time and it will get feckin hot really quick and fail very quickly , run a 60A alternator at 40A and it wont even break a sweat .
Son in simple terms
Lets say 10 turns of 1mm wire fit in a slot giving say 40A at a cut in of 900RPM rotor speed .
Now lets say I fit 5 turns of 2 x 1mm wire , still the same amount of wire in the slot but the output would over double , however the cut in would be around 4000RPM .

[Uncle Henry]

Got it. Great explanation Famous Dave. Thanks. I have to say that I'm still running a Lucas alternator, mainly because the "original" went doolally and cooked my battery. I had to replace both quickly at the time, so stayed standard. One day I will go small and neat like your cars.

UH

[Petowner]

Excellent write up Dave , giving us an description of your everyday job ,to a degree , we all have our specialities .
Hoping to upgrade to Denso myself .

Bob

[John A. Ross]

I have to say that I'm still running a Lucas alternator, mainly because the "original" went doolally and cooked my battery.
UH

Andy

Interesting as I used to see this on the compressors and big gennys all the time, had a conversation with peeps and most seem to have sen them on cars being open rather than shorted but guess it depends on the rectifier and regulator arrangements in fail mode.

I always fuse the alternator feed

[Uncle Henry]

Trouble was, John, I use small motorcycle style/racing batteries in Stan. At the time the alternator went rogue, the battery was in the rear passenger side cubby pocket and started to fill the car up with fumes.

UH

[John A. Ross]

Ah, even worse.

Those rear pockets need a better purpose, battery is a good one. I often thought of putting an Aux battery and dual charge in there.

John

[Dave Lane]

Gary Whitaker
very kindly sent me a Butlers map light FOC so it seemed only fair I fit it .
New switch , a rewire and an LED bulb and voila it lives

[Uncle Henry]

Those rear pockets need a better purpose

I have the Odyssey 680 in one and a DAB radio in the other

Famous Dave :- No headlining in the Vusky then ? Must say I'm surprised at that.

UH

[Dave Lane]

Famous Dave :- No headlining in the Vusky then ? Must say I'm surprised at that.

UH

Well it was a van so never had one , i like practicality of not having one to tear up ramming stuff in the back

[Dave Lane]

Fed up with small stuff vanishing in the Vuskys door pockets i knocked up a couple pockets .
Handy for Annies diabetic kit , masks , my vape etc etc.

[Dave Lane]

Vuskys tailgate lock fixed .
It was getting tricky to open with loads of play on the handle before the lock turned .
Turns out the tiny roll pin had given up and the square bar was wearing away , id already repaired this once decades ago.
Anyway I had some brass bar exactly the right size so fitted this along with a new roll pin .
Also threaded tother end with a 2BA tap so the bolt and washer could be fitted inside ,

Bit knackered



Removed the old bar



And fitted the new one with a new roll pin , you can just see the old one was split clean in two lengthwise , in the pic just above the new brass bar



Cut to length and a 2BA thread tapped in , i used a stud and nut come the end



And voila all fixed




FBF

[Petowner]

Lovely job Dave
Good that we can put our engineering skills to good use at home , l'll nearly always strip something down to repair it before buying replacement , not much beats me (apart from Frances that is), don't think l'd have that mentality if l'd worked in an office.
Just think how much a garage would charge for such repair, if you find one able or willing to do so.

Bob

[Dave Lane]

Just think how much a garage would charge for such repair, if you find one able or willing to do so.

Bob

I doubt youd find anyone TBH , Twas an easy enough fix as i had all the stuff ready