TR5 Wiring Harness and 15 ACR Alternator

[Cumulus]

I have a new TR5 Wiring Harness.

The alternator I own is a 15ACR.

The harness makes provision for the external alternator controller, which I will not use, due to the 15ACR alternator having an internal controller.

I am requesting confirmation on how to modify the wiring to connect the 15ACR correctly.

 

Below is the standard TR5 wiring  diagram.

 

From the research I have done, I have compiled the following:

·         The Alternator Control Unit connector block will remain in the loom

·         Disconnect the (NG Brown/Green) spade connector from the (F) alternator terminal. Insulate the spade connector. This wire will not be used.

·         Connect the (NY Brown/Yellow) wire to the Alternator (IND) terminal (no cabling changes required). This is already wired from the Ignition Warning Light to the Alternator Control Unit connector, and thus has continuity.

·         Connect the (NW Brown/White) wire to the Alternator Positive(+) terminal

·         Connect the (B Black) wire to the Alternator Negative(-) terminal, and connect other side ring terminal to ground point

·         Disconnect the (NR Brown Red) wire from the Starter Motor. Insulate the connector. This wire will not be used.   

 

Is this correct?

Dave

 

[Steves_TR6]

Before going to all the effort to install the 15acr i think you should consider if it is man enough for the job

i’d recommend an 18acr for any pi equipped car

steve

[RobH]

Your proposed wiring is OK Dave except you probably don't need the black wire. An ACR alternator usually earths through its body and has no separate earth connection.   There seem to be a couple of different connection schemes for a 15 ACR depending on its age and which regulator it has fitted. Normally there are two large spade connectors and one small one. The two big ones are both  +V output and you can connect to either or both of them.  The small connector is the one to the ignition bulb.  

If you have a photo of the rear of your 15ACR we could see which one you have.

As Steve says, the original 15 ACR is weedy, though I think  you can buy some now which have been beefed up. An 18 is usually the one to go for as it can supply more current but you might have to use a thicker brown/white cable to cope, or double it up and use both alternator outputs. 

 

 

Edited October 25, 2021 by RobH
typo

[Cumulus]

Thanks for the replies all.

Here is the pic of the rear of the 15ACR.

The Thick Black Wire is connected to Alternator Negative(-) terminal, and other side ring terminal attached to engine ground point

Dave

 

[RobH]

OK thanks Dave  - yes that is the older type regulator model so you are correct of course.    

You may find the current output capacity is a bit low as the rating is 28A max for that one at 6000 alternator rpm and less at lower speeds. No better than a dynamo really but if your old alternator was a 15 AC and was enough for you, this will do the same. 

(Do beware though if you ever change to a more modern ACR type. As I said above, on those the two large terminals are both positive output, and earthing one will kill the alternator.)

[Cumulus]

Thanks Rob

I went back to my original pics prior to starting the restoration and saw that I had no Ground on the Alternator. So maybe it was upgraded in the past to the newer type regulator...

It would be prudent then to disconnect the Black cable before I kill the alternator...

 

 

[RobH]

Probably a good plan if it was working OK without.