Alternator Wiring

[Guest Jomeo69]

 

 

is this diagram as simple as it looks?

Im soon going to be starting the wiring on my car and was just wondering if the cable that runs from the live side of the battery to the starter. Fine cool with that.

The alternator i have is a denso one with the same layout as the one in the diagram.

does the single connection (number 3) from the alternator run back to the + side of the battery via the starter solenoid?

So what is number 2 a switched live to?

Sorry if this seems simple.

Taa

ps this may be the start of a bout of posts about engine eletrics, tis due warning tis all.

[Guest george_lincoln]

Electrically the Alternator, Starter and Positive Terminal of the battery are the same, so running the cable to the starter, then to the battery normally saves having 2 cables running together, and probably saves big manufacturers a couple of quid a car.

 

I would imagine the connection from the fuse box is to do with the field coils, which need current to let the alternator work.

[Big Jim]

Point 3 is the main feed wire from your alternator, this needs to go to the +ive terminal of the battery, it can go via the starter, if they're both on the same side of the engine, so as to save wire, but doesn't need to. This wire needs to be nice and thick.

Point 2, is "switched live" from you ignition switch, it needs to be live when the engine is switched on to "energise" the alternator.

Point 1, is for the alternator light on the dash. You'll find that the feed to the light when the engine is not running, comes from the dash panel, and the wire to the alternator being the "return" but when the engine is running, and the alternator is charging, it then puts +ive feed up this wire, so there is then no "return" for the light, so the light goes out.

[stevedohc2b]

When I changed to a zetec I used the switched live from the old coil to go to the denso terminal 2 as this was being replaced by the zetec coil pack and new engine management loom.

 

Stephen

[peter_m7uk]

Point 3 is the main feed wire from your alternator, this needs to go to the +ive terminal of the battery, it can go via the starter, if they're both on the same side of the engine, so as to save wire, but doesn't need to. This wire needs to be nice and thick.

Point 2, is "switched live" from you ignition switch, it needs to be live when the engine is switched on to "energise" the alternator.

Point 1, is for the alternator light on the dash. You'll find that the feed to the light when the engine is not running, comes from the dash panel, and the wire to the alternator being the "return" but when the engine is running, and the alternator is charging, it then puts +ive feed up this wire, so there is then no "return" for the light, so the light goes out.

 

Hi Jim,

 

I'm going to get one of these alternators as well. On the diagram from the supplier, it shows terminals 1 and 2 joined together, but wondering if this would work? The ignition light connection must be switched live as well, or else the light would be on all the time when the ignition is off (unless a diode prevents this?). So, it sounds like it would work, but would the energising terminal need more current than the lamp could stand?

 

Pete