Alternator Installation

[jonnyb]

A discussion has arisen on the alternator on my 1622 engine swap thread and, from searching on the 1.5 section of the forum, I found no existing threads on this issue. I am sure there will be lots of discussion and knowledge to be shared so here goes. Discussion so far:

Hello Jonathan

I can't help myself to snoop about other owners garages.
In the photo of your 'engine in waiting' I see that you have replaced the dynamo with an alternator .

rileymotorclub.proboards.com/attachment/download/1283

Your work shows attention to detail, and may be interested in an alternate rear support bracket for the alternator, #12G1053.

rileymotorclub.proboards.com/attachment/download/1284

This bracket is readily available, (fitted to classic Mini ) and will allow you to remove the long rod you currently have fitted. Of course this may interfere with your bespoke ignition coil mount but I am sure you will come up with a work around.

Best lock your workshop door!

Bruce

Hi Bruce the alternator was fitted by the previous owner, who liked using black angle iron for custom brackets! Thanks for the heads up on the mini bracket, that is more elegant.

I agree Jonathan, although this bracket shown does accommodate the coil.

When you did this alternator install, (negative earth) how did you deal with the control box?

Bruce

[jonnyb]

Hi Bruce

As I said the alternator and new loom was installed by PO and I have no up-to-date wiring diagram with mods shown. It is on my "Round Tuit" list to investigate and update!
The Control "Box" is present but empty, so acting only as a terminal block.

Over to everyone else.

[canuck]

I have not done this as I chose to leave George positive earth. I sort of recently refurbished the control box and dynamo and I have a positive earth electronic fuel pump  so swap on my part would require me to correct the pump. I don't believe this will happen during my stewardship.
This is a nice to have if one is installing extra electrics. I drive my car a lot at night, and in rain and have never run out of electricity or flattened the battery.  Well set up car or lucky?  

If I know what I know,   the alternator is self regulating?

The large wire (output) at the 'F' terminal connects to the large terminal of the alternator and the (Y ?) smaller wire, 'D' terminal which is the sensing/exciter wire attaches to the small terminal? 
I confess I don't know what happens at the control box. I assume the regulating and cut out coils are taken out of the loop?  and maybe the earth wire is rerouted?  

Let's wait for more input, 

B

[ozieagle]

Hi,

From Paul Hunt's excellent MGB site

www.mgb-stuff.org.uk/charge1a.htm

Herb

[ahaugland]

One concern often overlooked when installing an alternator is that the potential output of the alternator often exceeds that of the generator, potentially requiring an upgrade to the diameter of the main charging wire or a secondary wire to the battery to charge. If you have an ammeter fitted, this would either require upgrading the wiring from the alternator to the Ammeter and from the Ammeter to the battery (usually via the Starter solenoid), if you want to have the ammeter tell you anything useful. The better option is generally to install a voltmeter in its place as it is far more useful information wtih an alternator and doesnt' require the full current of the car to run through it. If you connect the alternator directly to the battery or to the battery side of the starter solenoid, the ammeter will not read correctly, if at all. It is also easily possible to completely do away with the voltage regulator with an alternator that internally regulates its voltage (i.e. most modern alternators). The charge lead can be connected directly to the battery via the starter solenoid and the field terminal from the regulator can be joined with the ignition warning light, connected to the D terminal at the regulator. If you want to leave the regulator in place as a junction box, simply move the wire at the F terminal to the D terminal, using the other end of the Field (Yellow/Green) wire to connect to the smaller terminal on the alternator, and connect the wire from the Battery side of the alternator to the A or A1 terminals (which are internally linked in the regulator), but don't forget to upgrade that wiring as well as the wiring between the regulator and your starter solenoid.

[vue from the north]

when ever i start mine up im always amazed at how much the alternator is throwing in the battery, it make me realise how powerful the battery is to power the starter motor to throw the engine round,