fleetwood
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| posted on 11/8/05 at 06:54 PM |
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Alternators
Hi, bit new to this site so apologies to start with. Anyway to business, does anybody know if running an alternator in reverse is possible, this
means to say rotating in the opposite sense to the crank rotation, NOT as an electric motor obviously!.
Will the diodes or regulator be affected. I am fitting a 2.3 16v Scorpio/Transit (piece of Ford pig iron)precision engineering and am stuggling for
space at the front (back, bottom and sides),plenty of space above if the I.S.S would move over. Contemplating sticking the alternator out the front.
Though i'd seen somebody do it somewhere.
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VinceGledhill
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| posted on 11/8/05 at 10:17 PM |
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It doesn't matter to the alternator which way it rotates.
It will still work.
Worry not.
Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983
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omega 24 v6
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| posted on 11/8/05 at 10:44 PM |
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Strange I thought some of them were sensitive to rotation direction. Or is that only for the cooling fans.
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VinceGledhill
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| posted on 12/8/05 at 07:22 AM |
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The air will still flow. Although opposite to that intended.
Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983
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fleetwood
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| posted on 12/8/05 at 08:43 AM |
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Thanks for that.
Does the cooling fan make any odds?. The alternator won't overheat?
The other alternative is use a smaller alternator, I suppose which would make sense if have to move it. This is a 100A jobby(which I assume is far to
big), what sort of size is the maximum required.
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VinceGledhill
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| posted on 12/8/05 at 09:08 AM |
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Your alternator needs to be able to ballance the loads on your car.
In other words. If you demand is 100 amps then your alternator needs to produce more than that.
So lets have a look at my Locost and it's loads. Figures are all quoted higher airing on the side of caution.
Engine running.... Coil etc 3 amps
Lights on High Beam 55w x 2 = call it 10 amps
All side lights 5w x 4 = about 2 amps
I have no wipers or heater or heated rear screen. However the engine cooling fan for the radiator takes about 10 amps.
So.... do the maths... all adds up to about 24 amps on my locost.
Therefore a 30 amp alternator will still keep the battery charged with all the loads on.
I've got a corsa one that was fitted in my car for sale if you like. See the for sale section.
Yes the Fan is important.
Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983
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britishtrident
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| posted on 12/8/05 at 10:05 AM |
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Fan won't work properly, it is a centrafugal impeller and will still try and pull air through the alternator but because the angle of the blades
is totally wrong the flow rate will be about 1/20 of what it would normally be.
You could adapt the fan off an alternator from a 4 cylinder Honda or a Chrysler/Talbot Alpine.
[Edited on 12/8/05 by britishtrident]
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Bob C
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| posted on 12/8/05 at 01:54 PM |
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can you yank the fan off & refit it back to front? The fan will still work a bit, just not so good; it certainly won't blow instead of suck.
Alternatively You might be able to bend the blades with a chunky set of pliers to improve efficiency (might be worth a pop)
cheers
Bob
PS you can get thermochromic stickers from Farnell to tell you if you have a heating problem
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fleetwood
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| posted on 13/8/05 at 10:29 AM |
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Yeh I probably could, an will at some point. As Vince has righlty suggested I should look at a much physically and electriaclly smaller alternator
first, and then hack the smaller one about rather than destroying a perfectly saleable new one thats just to damn big.
Only just really esablished that the original mod I made to the alternator original mounting position to clear the frame rails now fouls the inlet
manifold, though I was safe, but there you go. Had to look a new inlet manifold anyway so will wait until that has been sorted and establish where
the alternator finally goes. Probably have to be stuck out the front on some sort of a diving board.
FEAD belts are another subject, considered driving directly of the water pump pulley probably to slow a ratio though.
Thanks for the advise though and thanks for the offer of the alternator Vince.
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