Alternator wiring Help.Totally confused .....

[oldgit]

Old alternator has died

but replacement has totally different set of four connections.Any kind soul prepared to enlighten me as to what goes where on new unit.

Engine is AQD40a diesel if that is relevant.

If it does not confuse matters I have dangling in the engine bay
1 x Thick heavy red wire with ring terminal
1 x slightly thinner but still heavyish red wire with ring terminal
2 x blue wires coupled together....poss neg/earth grounded to engine block
2 x black wire terminated with lucar connector coupled together with 61 marked on sleeve.
Like a total idiot did not note what went where before dismantling as assumed new would be same as old.

 

[Ken_Irby]

connections for valeo paris rhone alternator

the heavy red wire is battery + and needs to go on "+" . terminal "w" runs your revcounter. the thin red goes here. 61 is the ignition warning light and needs to go to 61. you will either need to replace the lucar with a ring or find a lucar male to fit the new terminal - the one on the old unit looks to have too small a ring otherwise you could pinch this. this leaves the blues to go onto "-"
Chas on Kentrina's login

 

[Billjratt]

Nobody else offering, so here goes...
Negative blue wires with rings to ' -' terminal (bottom right)
Both red wires to '+' term bottom left
thin black wires with lucar connector marked '61' to top left terminal marked 61 or 19 as it seems in the picture!!
notes: The blue wires to the engine chassis should be thick like the larger of the red ones.
If you have an isolated starter motor (having separate neg and pos connectors) it could be prudent to isolate the engine block to save electrolytic problems - take the double blue wire directly to the neg on the starter (or via a fuse rated as per alternator out put), instead of the engine block, and remove any connector to the block from the startermotor.
Essentially you should end up with a thick red going to the battery positive, possibly via the starter solenoid, and thick blues to the battery negative via wherever..(as above)
wire 61 should go to the ignition light, but you will need to cut off the lucar connector and crimp on a ring.
Not sure what the 'W' terminal is as I don't know that particular alternator, but it should be ignored for now.
If you have a meter (ohms) you can test the wires before connecting them/starting the engine -blue to batt- red to batt+. If you switch on the "ign" key the black wires should measure 12volts to ground.
hope this helps, good luck

 

[VicS]

There is awiring diagram in the owners manual! (Download from HERE if you have mislaid your copy)

But extracted below is the wiring of the alternator

B= Black 0.75mm². C= red 6 mm², H' = blue 2.5mm², H" = blue 1.5mm²

But that leaves the other red ...... must be same terminal as the one listed above

So
Reds on the + terminal, Blues on the - terminal, blacks on 61

Revcounter on this engine has its own sender ... it is not run from the W terminal.

 

[oldgit]

Thanks to all.

A heartfelt thank you to all who responded,....things did geta bit tense down in the engine bay during yesterdays warm weather.the prospect of b*****ing up two new alternators(it is a twin setup) did not appeal.
As a bit of history,one of my alternators,unbeknown to me,had died ages ago.
So when the poor old remaining unit gave up the ghost,due to me turning off ign key before pushing engine stop ? ,no charging at all.
Off to fix this morning...............Cheers.

 

[DannyB]

Thread Drift

Why oh why, in this day and age when every diesel car on the road can be stopped by turning off the key, do we still have marine engines that fry the alternator if you turn off the key when the engine is running ? How difficult can it be to modify the engine control to make it foolproof ?

 

[morgandlm]

Thread adrift

QUOTE<<Why oh why, in this day and age when every diesel car on the road can be stopped by turning off the key, do we still have marine engines that fry the alternator if you turn off the key>>ENDQUOTE

I assume when you refer to "turning off the key" you actually mean turning off the battery isolation switch since turning off the engine does not do any harm.

If you disconnect the battery of your diesel car when the engine is running you will probably blow the diodes just as you may on a boat. Quite simply, diesel cars do not have the battery isolation switch that many boats have, because I suppose, an inadvertently flattened battery is not such a problem. You don't have to use your battery isolation switch - you don't even have to have one at all. It's up to you.
Morgan

 

[VicS]

Why oh why, in this day and age when every diesel car on the road can be stopped by turning off the key, do we still have marine engines that fry the alternator if you turn off the key when the engine is running ? How difficult can it be to modify the engine control to make it foolproof ?

We can and we do. As stated above it's opening the battery isolator while the engine is running that causes the problems.

In fact among those I have studied the wiring diagrams for I have not come across any where the alternator output passes through the key switch and in which would turning the key off would cause any problem with the alternator diodes.

In many/most cases for some reason (to enable the engine to be started by hand with a dead flat battery perhaps) a fuel solenoid valve is not energised by the key so switching off does not actually stop the engine, it'll carry on running but with all the warning lights and instruments disabled.
Stopping is done either manually or by turning the key to an engine stop position where a stop solenoid is energised to stop the engine by cutting off the fuel.

 

[Seafort]

Field

We can and we do. As stated above it's opening the battery isolator while the engine is running that causes the problems.

In fact among those I have studied the wiring diagrams for I have not come across any where the alternator output passes through the key switch and in which would turning the key off would cause any problem with the alternator diodes.

Runing the output through the key switch would fry it, with the added problem of an extra place to disconnect the o/p (if the contacts could take it. Same effect as turning off at the isolator.

It is best to disconnect the "Field", usually through aux' contacts on a 1-2-Both switch.

Dave.

 

[VicS]

It is best to disconnect the "Field",

Yes to stop the alternator generating while the engine continues, to run but that's a different subject altogether.

 

[oldgit]

ta

thanks again to all who contributed.
All installed and up and running again.Just to add to the mix,a previous owner had also added some extra alternator wiring. !
When bought boat spent many happy hours stripping out bits of wire that wandered about the boat a lot but ultimately went nowhere most were connected to nowt.