Alternator Schematic

[stxboy]

Hi, I need some help with a wire schematic fo a valeo alt. thanks

[GordMay]

That's what you get for owning a Volvo.
This site may have some help
➥ Tiedemann Auto-Elektrik

[stxboy]

thanks I have a 4 wire alt system( 1 )tach (2) hr counter? (3) ground (4) bat+ wire this wire goes to the center lug of a bat isolator . I have no power on the bat + wire I have power on the other 2 wires on the isolator I have a yellow wire comming out of the alt and it goes to the bat+ lug on the alt. no output at alt, bat 9.8 volts the engines have been replace at some point with Kubotas. Iam a auto tech so I do understand wiring I just need a diagram or some Idea how this sould be wired it may have not been done right from the start

[GordMay]

An Alternator with 4 stator leads, is a Wye type. One of the leads is called the Neutral Junction. The Neutral Junction is common to all the other leads. Wye wound stators are used in alternators that require high voltage output at low alternator speeds. Two windings are in series at any one time during charge output.

[goboatingnow]

I think the term 4-wire the OP used is confusing,

What you have is a main ouput from the regulator the bat + , and two aux outputs ( if I understand you correctly)ole thing being internally regulated. The outputs will be diode seperated and it sounds like the main diode on the bat+ line is gone. The yellow wire is the sense line from the regulator and as its connected at the alt, its "machine sensed"

[stxboy]

There seems to be only 1 output on the alt it has Bat+ and Bat- these are big 10gage wires the yellow wire coming out of the alt hooks to the Bat +. There is no power at the bat+ wire . On every alt system I have worked on it has power on it coming from the bat, but on this it goes to the isolator. I checked the other engine it is the same. The engine bat is only used on start up, but the alt should charge the house bat. Does the alt sense it is spinning and then start charging without any power coming from the bat ? Are does someone have this wired wrong or a bad Isolator .

[goboatingnow]

ok , you have a valeo isolated ground alternator. so the B- should be to ground, The W terminal is the tach and the othe6 rone normally marked "61" is the ignition/idiot light/ field coil excite, this should have power on it, when the ignition/starter key is turned.

If your battery positive cable runs through a diode isolater, then there will not be power ie 12V on that terminal with the alternator not running. However power should appear once the alternator spins up. If not either (a) The field /excite supply via the "61" terminal isnt powered or (b) The diode trio is gone on the alternator, this could happen if the battery switch was disconnected with the altermator running.

ogh 61 could also be labeled d+

[stxboy]

Thank you for the help to understand the system it was a bad reg in the alternator. Knowing how the system works was key thanks again