Alternator madness

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shadwell

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Can anyone help. I'm having problems with an alternator fitted to a Lister SW2. Having replaced a dodgy alternator (warning light just glowing and hardly noticeable) the new alternator is just the same. I have isolated the charge circuit from the rest of boat wiring with no change. Is the rotation direction relevant as the pulley rotates anti clockwise with the Lister set up
 
Have you taken a wire directly from the terminal to the warning light bulb? Presumably the new alt is the same model, or is that why you have rotation doubts cos it,s different? Had a very similar problem last year, turned out to be a simple fault in the alt,. Although it took four visits to the alt fix it man to discover, which was a right pain cos tight spot the alt lives in. Think it was hairline crack on something on the exciter side of something. Notes are all on the boat + some copies of PDF files sent to me by friendly Forumites. Let me know if your still in shtuck I can go get em Sunday Pm. Good luck it,s bloody frustrating been there Tshirt and all that /forums/images/graemlins/frown.gif
 
Thanks Kawasaki I have the alternator connected directly to the battery including a new warning light circuit separate from any other boat wiring. Running out of ideas other than faulty new alternator hence even considering issue of rotation direction
 
No it's a refurbished "new" job. The original alternator Lister spec was a Lucas 11ACR. This one is 16ACR lookalike and I'm thinking it maybe either "duff" or not the correct alternative. Thanks for your help.
 
Was there an 11ACR, thought it was an 11AC with a seperate remote regulator module. Looked the same as the 16ACR.

Brian
 
Halcyon your quite right and Kawasaki yes the terminals are the same I suspect there may be a fault on the boat that caused the new alternator to fail /forums/images/graemlins/confused.gif
 
But if you have fitted a 16ACR, this has the reg built in, pins look the same, but the little one has a differant function.
The old system will have the warning light connected via a relay, or the regulator, the small pin on thr 11AC is for field control.
On the 16ACR the little pin is the ground for the warning light, simplictically.
What have you connected to what?
What has happened to the old reg?

Brian
 
No, when I said the original was an 11ac I meant when the engine was new. The 16acr I put on was to replace a previously fitted 16acr by someone else. The warning light is fitted to the small terminal as it should be. Sorry for the confusion.
 
What is the voltage on the feed side of the warning light, the output site of the lamp, and the voltage on the little terminal on the alternator?

Brian
 
halycon is right voltage needs to be known. Don,t worry mate lectrikcery is confusing cos you can,t "see it" hopefully you may just have a "crossed wire"! /forums/images/graemlins/shocked.gif
 
12 volts supply to the warning light not sure voltage on other side of bulb haven't measured it but using about 4 watt bulb and about 5 ft single cable to alternator all connections good
 
Sorry but we need actual voltages.
A dim warning light is not a common fault, having two of them is odd.
It could be over voltage output, or under voltage field, normally a field diode fails short circuit allowing 1 phase in three to go to ground, allowing a lot of little pulses or a dim light. you can have the same with a short circuit diode.
But two together is odd, sounds a bit like the old alternator cleaned and sold back to you, but voltages is stage one.

Brian
 
Couldn't wait till Tuesday driving me mad. Alternator removed yesterday for testing, meanwhile done some rooting around. What would be the effect of putting 12volts directly to the small field terminal instead of via the warning light ??
 
Make very little differance, bar you would not know if the fault was there, or the alternator stopped charging.

Brian
 
The small terminal is feed by the field diodes. on your alternator thay are the same as the main diodes, feed from the same stator winding as your main output, infact when running the bulb is dead, it does nothing, all power coming from the field diodes.
What do you hope for?
The voltage reading are more likley to tell you something.

Brian
 
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