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+--- Thread: Alternators for Mag engines (/showthread.php?tid=4855)
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Alternators for Mag engines - bobthompson - 24-08-2020
Does anybody have any knowledge of alternator conversions for Mag engines? Is there anything that can pick up from the existing drive?
RE: Alternators for Mag engines - Charles P - 24-08-2020
(24-08-2020, 03:53 PM)bobthompson Wrote: Does anybody have any knowledge of alternator conversions for Mag engines? Is there anything that can pick up from the existing drive?
I asked the question of the UK supplier.
His answer was that he believed their alternator fitted all models of Austin 7. I gently pointed out the differences, supplied a couple of pictures and asked if he had any plans. The answer was no.
c
RE: Alternators for Mag engines - Stuart Giles - 24-08-2020
Don't know of anything that would just bolt on, But I have one of these in the workshop to fit onto an A7 project where there's not enough room for a dynamo or a dynamator. Wouldn't be too difficult to adapt to a Mag engine.
https://www.ebay.co.uk/itm/Alternator-For-Kubota-Lawn-Tractor-G1800-G1900-G2000-G3200-G4200H-G5200H-G6200H/263828513246?hash=item3d6d67a1de:g:iF4AAOSwM1hbUuz7
It's a really small permanent magnet alternator; pushes out 14A @ 12V maximum. Needs an external regulator, there is a version of these that will drive an ignition warning lamp -but not so useful if you have the SM3 switch panel. I bought my alternator and regulator from a US supplier, even after paying the shipping etc. it was still cheaper than the ebay item I linked to.
RE: Alternators for Mag engines - Robert Foreman - 25-08-2020
Very interesting Stuart.
Could you please furnish me with some dimensions?
Regards, Robert.
RE: Alternators for Mag engines - Stuart Giles - 25-08-2020
Certainly Robert, might take me a day or two to locate the box it lives in. Obviously looks nothing like a mag dynamo, but would be nothing like as obtrusive under the bonnet as the Citroen 2CV or Nippon Denso altys I've seen used.
BTW, I found out about this alternator and regulator setup from some old bike people, has better reliability more poke than most 60s/70s bike altys, the regulator is also a lot more sophisticated than the "boil your battery dry" Zener diode setup fitted to lot of machines back then.
RE: Alternators for Mag engines - Colin Reed - 26-08-2020
HI All.
Dimensions
HI ALL,
Just an update the alternator does not require input voltage to work only the regulator as you will see from the size of the heat sink they need to be fitted in a open space to allow for cooling
Colin
NZ
RE: Alternators for Mag engines - Stuart Giles - 26-08-2020
Colin,
Well done for that; your drawing has saved me some rummage time!
And yes, being a permanent magnet alternator it doesn't need voltage to excite the alternator's field; but also, this means that there is no control over the permanent magnets' field strength, so the regulator needs to sink some energy when full charge isn't required by the battery.
The only factory installation I've seen of one of these had the regulator mounted to the garden tractor's metal frame, allowing it to act as a heat sink. Otherwise, it didn't appear to be in an especially well ventilated area.
RE: Alternators for Mag engines - Robert Foreman - 26-08-2020
Thank you Colin and Stuart.
What kind of revs does it need to produce a good charge?
RE: Alternators for Mag engines - Charles P - 26-08-2020
Some interesting tales from the motorcycle people here (and exploded pictures)
https://impbarn.blogspot.com/2011/12/sunbeam-s7-s8-permanent-magnet.html
and
http://www.britbike.com/forums/ubbthreads.php/ubb/printthread/Board/2/main/63870/type/thread
Edited to add
https://www.autoelectricsupplies.co.uk/product/1176/category/250
Shows output vs rpm
Charles
RE: Alternators for Mag engines - Colin Reed - 26-08-2020
HI Stuart,
I was just lucky mine was still on my bench from last week other wise it would have been put in a safe place never to be seen again
(Old Age )
Colin
NZ