Replacement Alternators P6B 1971

6Bcygnet

6Bcygnet

Member
My alternator has died. I have been offered a Lucas alternator 12/10 NB Elektrik. This fits physically.
My original alternator worked through a Lucas type 11 AC control box. The new alternator has an internal control.
Now the tricky bit. Wiring! The B+ output (brown-white) to the ammeter is fine, as is the AL connection (brown-yellow) for the warning light.
I assume that the alternator needs an initial excitation current, or does it?
On the new alternator there is a large pair of spade connectors (common bond) and another smaller connector which I was told was for the tachometer which I don't think I need.
Originally there were two leads from the alternator to the control box. One black purple - Alt. field pos. to Control box pos. And one brown green lead from the Alt. field neg. to Control box neg.
If the common spade connectors on the new Alt. are positive, then if I remove the control box and join the spade connectors via the brown purple lead to the brown blue lead exiting the control box, I will have connected the ignition switch to the spade connectors.
I will then have a positive lead from the alternator to the ignition switch. This will give a 12 volt feed to the alternator when I turn on the ignition. The other brown green lead of course will be removed.
Anyone any views before I commit a foolishness?
Frank H.
 
Hello Frank,

Was no one able to overhaul your 11AC? It might only need brushes, in which case there are some here.....http://cgi.ebay.com.au/LUCAS-11AC-ALTER ... 0490558955

If the actual 4TR control box is at fault, then these people have new ones....http://www.jonniejumble.co.uk/classic_c ... ucas.shtml

Or if it is the diodes then....http://cgi.ebay.co.uk/LUCAS-11-AC-ALTER ... 0616589958

Unless the your engine has over 200,000 miles, then the alternator slip ring is likely to be ok. Apart from that there is very little else that can go wrong. So almost certainly the problem can be fixed with one or more of the above.

Ron.
 
Thanks for your reply Ron.
We can get all the brushes etc but the windings on my alternator have gone.
I use the car a lot and am happy to replace the alternator. As the car is a hobby I like to do work myself, when I can.
This time I have been to an auto electrician who will organise the wiring for me. I don't want to wreck a new alternator.
It is a simple job he tells me, and should take less than half an hour.
Cheers
Frank.
 
Hello Frank,

Glad to hear that you have sorted the problem. Just out of curiosity,..how did the windings fail? I assume you mean the windings on the rotor?

Ron.
 
SydneyRoverP6B said:
Hello Frank,

Glad to hear that you have sorted the problem. Just out of curiosity,..how did the windings fail? I assume you mean the windings on the rotor?

Ron.
Click to expand...

Hi Ron

I had an alternator about 18 months ago that had been reconditioned but the stator windings were on the way out and they're not something the supplier said he would replace on a standard recondition. It caused me all sorts of problems with tracking the fault because the alternator would work then not work etc. Eventually it stopped working altogether and gave an open circuit when I checked the windings. So it can happen, probably just not very often.

Dave
 
Dave3066 wrote,...
Hi Ron

I had an alternator about 18 months ago that had been reconditioned but the stator windings were on the way out and they're not something the supplier said he would replace on a standard recondition. It caused me all sorts of problems with tracking the fault because the alternator would work then not work etc. Eventually it stopped working altogether and gave an open circuit when I checked the windings. So it can happen, probably just not very often.

Dave
Click to expand...

Hello Dave,

I am always curious as to why things happen. I accept that nothing lasts forever, but some things should certainly last longer than they do. With your alternator, the stator windings are the fixed windings that run around the inside of the housing, so how did they come to fail?

Ron.
 
SydneyRoverP6B said:
Dave3066 wrote,...
Hi Ron

I had an alternator about 18 months ago that had been reconditioned but the stator windings were on the way out and they're not something the supplier said he would replace on a standard recondition. It caused me all sorts of problems with tracking the fault because the alternator would work then not work etc. Eventually it stopped working altogether and gave an open circuit when I checked the windings. So it can happen, probably just not very often.

Dave
Click to expand...

Hello Dave,

I am always curious as to why things happen. I accept that nothing lasts forever, but some things should certainly last longer than they do. With your alternator, the stator windings are the fixed windings that run around the inside of the housing, so how did they come to fail?

Ron.
Click to expand...

I've no idea Ron, but the supplier said he always replaced rotor windings when reconditioning and to replace the stator windings too would either wipe out his margins or make it too expensive for customers. I sent the unit back and he gave me another one. I suspect the windings had been subject to abuse, perhaps through contaminants or water ingress, at some stage and just chose that moment to give up. I'm always curious as to why things fail too, must be the engineer in me :)

Dave
 
Hi Ron and Dave
The electrician easily rewired my alternator by disconnecting the Rover's voltage control and bypassing the warning light relay.
That is the aluminium tube by the drivers right knee that I thought was the flasher unit relay. It took about five minutes.
The alternator works well and I assume the internal voltage control also replaces the function of the previous external relay.
As to why the original failed, I don't know, other than that I was told it was a three phase alternator which had failed on one phase.
This makes sense, because for the last few years the Ignition warning light flickered at low revs unless I had some load on it.
There was no obvious signs of damage - externally- so I can only assume a broken wire in the windings.
Regards
Frank
 
Hello Frank,

Good to hear that your alternator is all sorted and running nicely again... :)

Thanks for the update!
Ron.
 
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