I'm halfway through converting from a generator to an alternator - I've done all the wiring and have got to the testing. I have put a 17ACR on, which is an early type with 4 connections, two fat ones (+ and -, although I think they are both output), the IND and B+. So far I have only plugged in the + and IND, thought I'd leave B+ for the moment.
When I turn the ignition on, I get no warning light. However it does turn on when you ground the IND wire at the alternator or use a test light. The B+ wire is supposedly a sense wire of some sort and should be connected to the solenoid. So I tried that. Then the ignition light is always on until you switch the ignition on, then the light goes out.
My question is this. Does anybody know what the B+ wire is supposed to do and could it be the cause of the problem, or is the alternator just knackered? It is untested until now.

<edit>I just tried something different and put the test light on B+. If I do that (as in earth it) then the ignition light comes on and appears to do the correct thing. However I'm reluctant to wire it to ground since the only reference I can find to the B+ says to wire it to the solenoid, and when I did that no smoke came out. So now I'm confused. Also, I plugged the wires into another alternator 16ACR and still no luck with the idiot light, and that doesn't have the B+ connector. So now I'm more confused

Problem solved.
17ACR = No worky.
16ACR = No worky.
15AC I found in the back shed = worky.

The 15AC isn't a huge leap forward in terms of amps but it keeps a constant 13.7 at any speed, going down to about 13 with the lights on at idle. The generator would go to 15V with no load and quickly go to less than 12 with the lights on. Interestingly, the ignition light seems to work properly but as soon as I turn the motor on it goes out and doesn't illuminate at all no matter how low the idle. I thought they kicked in at about 1000rpm? I hope this isn't a problem.

Once light goes out it stays out with an alt. They spin faster, and give more output at low rpm than a generator does.
Generator was rated at 22A, the 15AC is 28A.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Anto,
I found some Lucas installation instructions for the 17ACR alternator.
It is only suitable for -VE earth systems. Wont work on +VE earth systems.
Since you are converting from a generator did you change the battery over to -VE earth?
B+ goes to the +VE battery supply, usually at the solenoid.
IND goes to the warning light and then to the "IGN ON" side of the ignition switch but you also have to have a link wire between the 2 terminals marked IND, just above the B+ terminal.
+VE also goes to the +VE battery connection at the solenoid.
-VE goes to an earth point on the engine or body.

Hope this helps.
RonR

If you don't change the polarity to <-ve> earth, the alternator lets the Lucas smoke out of all the diodes when connected. Not pretty, and the wiring suffers too.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Car was converted to negative earth a long time ago. By the sounds of it the 17ACR I have has buggered diodes or similar, I connected the B+ to the solenoid and strange things happened with the ignition light. I didn't bother earthing the -ve plug, I figured it earthed through the engine like other alternators.
The 15AC I put on works fine, the main reason I didn't put it on in the first place was that I'd pulled it apart and couldn't get it back together, took my mate 10 seconds to figure out there was a small hole in the back to allow you to hold the brushes in during reassembly!
Works a treat now. Don't know why I didn't do it sooner (well, the generator did work fine). I ended up ripping the internals out of the regulator and turning it into a terminal box. Easier than soldering 5 thick gauge wires together.