Alternator Terminals - help please

[bob_tyler]

I am fitting a switch to supply my two battery banks.

I need to find the "Field" terminal on the alternator. The only one I can find that looks right is marked "IND".

Is that the field terminal please?

 

[Stemar]

I'm no expert, so not sure about terminology, but I assume it's the feed to the field coils, which will be at about 0v when the alternator is not charging and +12 when it is. If so, turn the "ignition" switch on and make sure the charge warning light comes on. Now turn it off and diconnect the lead you think - it'll be a relatively thin one, not the thick output lead. Turn the ignition back on and see if the alternator warning light stays off. If so, you've got the right lead.

You can download The 12v Doctor's Alternator Book from here, but it's about 6 1/2 MB, so may take a while

 

[bdsweeting]

Hard to say without knowing which make the alternator is.

I would assume at the moment that there is a large diamtere wire coming from the machine and going to the batteries. There should also be a smaller diameter wire which probably comes from the charge light on the dash. That wire is the field terminal normally.

You could also try http://www.motoren.ath.cx/ where you can download an alternator handbook.

Good luck.

 

[William_H]

There is a strong chance that you have an alternator with built in regulator. That is a small (possibly) black plastic box at the back opposite end to the pulley with 2 screws and possibly the smaller terminal attached to the box. This will be your wire to the gen light or in other words the supply of 12vDC excitation for when the alternator has not started generating its own excitation power. This line may also supply the sense of exactly what voolltage is being generated. It sounds a bit like you are going for battery sensing after going through splitter diodes. it may work but there are so many variations on alternator connections perhaps you should leave as is and go for a Voltage Sensing Relay to paralell second battery when the engine battery is being charged. Leave the alternator wiring as is. will

 

[VicS]

"IND" is the connection to the warning light. If there is a field connection it will probably marked "F"

There will normally only be an external field connection if the alternator has an external regulator.

Internally you may be able to identify the field connection as it will be to one of the brushes, the other brush being earthed, but the brushes and regulator are sometimes combined as one unit.

 

[trouville]

Your link dosent work, and the Dutch link wont go to either the engins nor the good food site???

 

[Stemar]

[ QUOTE ]
Your link dosent work, and the Dutch link wont go to either the engins nor the good food site???

[/ QUOTE ]It worked when I tested it, honest!/forums/images/graemlins/confused.gif

The motoren link on BDSweeting's posting works. The site isn't always reliable, but seems to be working now. If anyone needs something from it and can't pick it up direct, I've probably got it (sad, I know /forums/images/graemlins/smile.gif )and can email it if you PM me with an address.

I also have a circiut diagram for a very simple and cheap relay operated split charging system. It's not sophisticated, but it works on my boat and has the advantage over diodes that there's no voltage drop. Total DIY installation cost from £5! Again, PM me if you're interested.

 

[Guest]

Link seems to be blocked by YBW ..... server refuses to connect.

/forums/images/graemlins/shocked.gif

 

[Steve_N]

There's a nice cross reference of alternator connection names by manufacturer here. May be of use to you..