24 Volt alternator wiring help

[CRS51]

Hello all, would anyone be able to help with the wiring connections on my alternator ? I have the + and - connected directly to the batteries via a large isolator but I'm unsure which connection is the warning light, any help would be much appreciated.
I should say the engine (Cummins 8.3) is from a 1993 Dennis hookloader and has been fitted to a 1958 Leyland recovery truck.
Thanks Chris.

 

[8ob]

Some of these alternators are externally regulated, have you got a serial/part number?

Bob

 

[CRS51]

Some of these alternators are externally regulated, have you got a serial/part number?

Bob

Hello Bob I cannot find any makers plate or serial number on it unfortunately

 

[8ob]

Hello Bob I cannot find any makers plate or serial number on it unfortunately

I will flick through my alternator book tomorrow and see if I can identify it, once you know what it is the book also has the wiring layout.

Bob

 

[CRS51]

Thanks Bob

 

[knighty]

I'm no expert on this stuff....

the small spade connector at the bottom is almost definitely the warning light (it's the smallest connection by far and it's out on it's own)

the 3 screw connections above that will the the 3 phases generated by the alternator... looks like it has a built in regulator and that's just where it connects on

where you've connected your positive and negative, the bigger studs next to those, the ones on the body of the alternator itself, with the + and - next to them, I think those are your battery connections, the connections you've used look a bit weedy to me, the battery connections are the highest amp connections, so makes sense there's the larges connections (logic+fits with every alternator I've worked on)

I think you've joined your wires onto the field and stator connections, which like the 3 screws, you don't need to connect anything to

I'd be confident enough in that to wire it up like that if it was mine... but there's no guarantees it's right or that you don't have an odd/quirky alternator that doesn't fit the standard idea of alternators.

if you're worried... connect it up with a bulb between each alternator connection and the wire... bulbs should all go out if it's right (might be on very dim) and the bulbs will act as fuses and pop if anything major is wrong

 

[CRS51]

Here are a few more pics from today, going to have another go tomorrow.
Cheers

 

[knighty]

you could try spinning it with a drill/anything on the bench where it's easier to mess around with the wiring?

 

[CRS51]

you could try spinning it with a drill/anything on the bench where it's easier to mess around with the wiring?

Thanks Knighty but I am unsure of what voltage I should be getting from where. I have tried spinning with a drill with the + and - connected directly to the battery but there is no voltage increase at the terminals.
Is there a maximum/minimum wattage of bulb for the indicator light ?
Cheers

 

[knighty]

from tests I've done (with 12v alternators) anything worked for the warning light

you need to check the battery voltage, it should rise when you're making power

you need to spin it fast, really really fast

it should pretty much free wheel at first, but once it's making power it'll create so much drag your drill won't be powerful enough to keep it spinning and you'll feel the drill working hard


I still think you need to be connected to the much bigger +va and -ve bolts

check the -ve one with a meter, see if it's connected to the alternator frame, they almost always are (it would be a special/rare alternator if it isn't connected)

 

[Woody.v8]

With the + and - connected to the battery's, get your meter and see which other terminal you are getting a + voltage at, This is usually the exciter and needs a bulb in series with it going to ground unless you know which wire is the batt light on your dash , then use that.

 

[knighty]

with the battery connected up the wire for the warning light should be negative, and then turn positive when the alternator starts making power

if you have one handy, you could put a bulb in the pattery positive you use... that way you can;t short anything out, it'll just light the bulb instead :-)


for testing, skinny wires will do :-)

 

[CRS51]

Thanks for all the help, I have managed to get it to charge. I wired up the large + and - straight to the battery and the small terminal at the bottom to one side of a bulb the other of which went straight to the battery +
The problem was the small black wire with the bullet connector in the pics was not connected to battery negative.
All seems good and certainly makes the drill work for a living, charges at a steady 27 volts and when I stop the drill the light comes back on so I am presuming all is well.
Cheers Chris.

 

[knighty]

sounds good to me :-)

 

[knighty]

thinking more about it that black wire needing to go to the battery confuses me a bit... if that needs to be connected to negative, you'd think they'd have it connected to the big main negative?

(unless it was originally and the big ring terminal it was connected to has gone missing)