Jump to content

alternator wiring question


Featured Posts

I have just returned from an eventfull trip to Ely with my partner and the kids, Everything was fine untill we ran out of battery pwer in the wild fens.

I went to start the engine only to discover that the television switched off and the engine wouldn't turn over, I thought this was strange as the leisure battery and starter battery are on 

seperate systems, I checked the voltage on boyh battrys , they were both the same 11.54, this again I thought was strange, this emplys both batterys are connected as one and 

the split charge relay was permanently on. I limped back to ely , I replaced the switch and charged the battery only to discover that I am not getting a charge from the alternator, the alternator is new so I am hoping that I have wired it up wrong.

alternator part no 382-08919

it has terminals W or M

B+ 

3 spade connections 

at the moment the exciter cable from the ignition goes to the spade connection and the charge to my battery is from B+, is this correct,

I think i have the connections the wrong way round.

thanx in advance

Link to comment
Share on other sites

10 minutes ago, galaxyranger said:

I measured the terminals at W and B+ and got a reading of zero and from the spade terminal I got sparx and shat myself.

Does this mean the live is from the spade connection. The pully belt is tight

Yes you will that terminal is live connected via the one next to it straight to pos+ battery post. If you have a multimeter its safer to check at the battery that the red cable from the alternator goes to. Meter set to 20vdc, red probe on the pos terminal and black probe on the neg terminal, Run engine at fastish and you should get a reading of  between about between 13.5v and 14.4v depending on the charged state of the battery.

Edited by bizzard
Link to comment
Share on other sites

According to Tony Brooks A127 diagram your main red pos cable is on the the B- terminal and should be on the B+ terminal. BUT I see a bit of black paint on that cable behind the terminal which might be marking it as a black neg cable,  so is it really a neg- cable?   if so your missing the main red power cable on the other vacant nut terminal.  Trace that cable

Edited by bizzard
Link to comment
Share on other sites

 the red cable with the blck tape goes to the positive on the battery , i am pretty sure the other end is attached to the B+ terminal, but i didn't get a reading from that terminal but got sparks from the three spade connecters, this is the live feed no.

thanx for input, if i swap the connection over and its wrong , everthing will be ok or will there be sparks

cheers

Link to comment
Share on other sites

Tony Brooks terminals on the Lucas A127 diagram are in slightly different places than on yours. If  that red cable on the nut terminal does lead to a pos+ post on a battery, ok. The other W nut terminal is for a rev counter.

Link to comment
Share on other sites

3 minutes ago, galaxyranger said:

 the red cable with the blck tape goes to the positive on the battery , i am pretty sure the other end is attached to the B+ terminal, but i didn't get a reading from that terminal but got sparks from the three spade connecters, this is the live feed no.

thanx for input, if i swap the connection over and its wrong , everthing will be ok or will there be sparks

cheers

Thats correct then.  Yes you will get sparks as you you must have touched the metal body at the same moment. That big spade terminal is an alternative B+ and is connected internally to the B+ nut terminal.

Link to comment
Share on other sites

Ok then I'd carry on and do the multimeter test. Red probe on that B+ nut terminal and black probe on the alternator body.  Or at the battery posts like I've already mentioned

I can just make out B+ stamped on the alternator body just below that nut terminal, so definitely correct.

Edited by bizzard
Link to comment
Share on other sites

Yes. The cable attached to the spade connection goes to the warning  lamp and ignition. 

When I got sparx it was from the large spade connection  next to the warning lightcable.connection. 

I checked  with a multimeter with the cables in 5heir current location at the battery terminals whilst the engine was running and the reading didn't go up at all.

I will cracking on tommorow 

Thanx

 

 

Link to comment
Share on other sites

C

11 minutes ago, galaxyranger said:

Yes. The cable attached to the spade connection goes to the warning  lamp and ignition. 

When I got sparx it was from the large spade connection  next to the warning lightcable.connection. 

I checked  with a multimeter with the cables in 5heir current location at the battery terminals whilst the engine was running and the reading didn't go up at all.

I will cracking on tommorow 

Thanx

 

 

Check at the alternator to make sure.  Red probe on B+ nut and  Black probe to body, engine running fastish revs.

Link to comment
Share on other sites

Have to say that red cable looks rather thin to me. It should be at least 16mm Csa and preferably 25mm it looks about 4mm. Is their no other thick red cable that’s hanging about? 

 

It might be worth checking the engine/alternator are connected to battery negative. Put your voltmeter between the battery -ve and the b- or body of the alternator and their should be 0 volts (or very small reading ) 

Link to comment
Share on other sites

I am not too happy about the way what looks like yellow insulating tape on the B+ cable is marked bby what looks like an upsand of metal on the diode plate inside the alternator. If its  the positive plate its OK but if its the negative it could cause a nice short circuit.

7 minutes ago, jonathanA said:

Have to say that red cable looks rather thin to me. It should be at least 16mm Csa and preferably 25mm it looks about 4mm. Is their no other thick red cable that’s hanging about? 

 

It might be worth checking the engine/alternator are connected to battery negative. Put your voltmeter between the battery -ve and the b- or body of the alternator and their should be 0 volts (or very small reading ) 

With the alternator charging, without it will read zero.

Link to comment
Share on other sites

18 minutes ago, Tony Brooks said:

I am not too happy about the way what looks like yellow insulating tape on the B+ cable is marked bby what looks like an upsand of metal on the diode plate inside the alternator. If its  the positive plate its OK but if its the negative it could cause a nice short circuit.

I agree, it caught my eye too. I think it’s a yellow crimp though but even so should really be rotated away from that metal tang. 

19 minutes ago, Tony Brooks said:

With the alternator charging, without it will read zero.

And of course, right now it isn’t. Hence this thread. 

Link to comment
Share on other sites

1 hour ago, Tony Brooks said:

I am not too happy about the way what looks like yellow insulating tape on the B+ cable is marked bby what looks like an upsand of metal on the diode plate inside the alternator. If its  the positive plate its OK but if its the negative it could cause a nice short circuit.

With the alternator charging, without it will read zero.

I studied that little cleat on that B+ terminal connector too.   I think its plastic. The yellow bit is the eye terminal plastic insulation.  What worried me was what turned out to be black insulting tape behind it. At first I thought someone had used that red cable as a neg- cable and marked it black with the tape to distingquish it as such, as happens quite a bit when someone has,'t got the correct coloured cable for a job, (quite confusing) That's why I insisted he traced that cable, which he did,, to the pos+ battery post, so ok.

Edited by bizzard
Link to comment
Share on other sites

3 minutes ago, galaxyranger said:

The yellow is a plastic crimp. The plate it touches is the B+ spade connection. I was going to put a female spade connection  on that cable and try it in the large spade connection.  I am a bit confused. Nothing out of the ordinary. Shall report back with info in while

Cheers

Leave the B+ cable on that B+ nut terminal, much better than the spade connections. Is that little cleat gripping the yellow bit of the terminal, plastic or metal??

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.