Volvo Penta alternator wiring

[dalex]

Hi folks,
Calling on the powers of you all in the hope I can get my alternator charging again!
I removed the alternator from the starboard of a pair of AD41B's, and like a total waarrt, forgot to note where the wiring goes, guessing it was the same as the port engine. How wrong I was! It is quite awkward to get to the alternator, and the only way to se what's going on there, is by using a mirror.
Ok the alternator has 4 terminals, and doesn't correspond to any diagram I have of any volvo engine. The terminals are B+ (Nice and easy that one!). This has +12.6 volts wrt the engine block. There are 2 reasonably thick wires which fit on this, and there is a hint of red exposed in the insulation. A yellow wire runs from this terminal into the body of the alternator. B- (This is strapped to the engine block on the port engine, so I did likewise on the stbd. There is a round connector which fits over this, with 3 wires crimped together.
The alternator has 2 smaller terminals, W - which I reckon goes to the rev counter. There is only one wire which has a ring terminal on the end, which fits this accurately, and will not fit on any of the other terminals, so this one gotta be right, yes? Finally, D+. On this 'd+' terminal, is one wire slid on to a spade connector. (Not sure, but think this should go to the warning light). There was a gray wire with a round terminal which has a hole large enough to fit over the largest terminal, so this could go anywhere! Connecting this to the D+ terminal gets an erratic reading on the rev counter when the engine is running. The wiring has been hacked in a former life, and there is an extra wire with a 'U' shaped connector on it, and the other end of this goes to a group of 3 wires. All the wires have a thick coating of green volvo engine paint and my attempts at removal amounted to naught using a handful of wire wool to clean the insulation, until my hand ached so much I couldnt grip the damn wool any longer
The rev counter over-reads quite a lot, so I'm not sure if I have the wires correct to that. The battery warning light comes on as soon as the ignition is switched on. There is no sign of any generator light coming on.
Checking voltage at the D+ terminal, gave 2.6volts with ignition off or on.
The alternator was taken to a repair shop, and the kind chap pronounced it working perfectly. I have almost certainly messed up the wiring, so need to go back to first principles with it. The alternator was certainly charging ok prior to removal so the wiring configuration worked once... Any ideas?
Thanks in anticipation!

 

[Kurrawong_Kid]

Older Volvo alternators were usually wired as follows: B+ to starter motor: DF to external regulator- to earth and negative(earth) wiring for instruments:61(red) to regulator and warning light and power to instruments and revcounter. Suggest you look at an electrical book with equivalent signage to try to work it out from there. Alternatively look at the other alternator and try to check signage-B- and D- are easily confused on a dirty alternator in a dark situation. Please don't follow this slavishly-only offered as some guide. Try to follow it with the other engine first. As for the gray wires-what does not work on the boat? Most likely could be an earth return from somewhere and something added later, but who knows? Trust these thoughts are of some help.

 

[dalex]

Thanks for the reply. The marking on the alternator is very clear. Just the 4 connections: B+, B-, D+ and W.
I am convinced that the alternator has an internal regulator. Apart from 12.6v, engine running or not, the lack of ignition light, and erratic rev counter, everything ele works ok.
The diagrams I have, show an alternator as you describe, with the 61 terminal. I must presume my alternator is of much later pedigree than the one shown on the diagram.
My next stage of investigation, is to disconnect all thin wires which are not at 12v and ground them, whilst someone observes the lights on the console. I guess, one should kick the rev counter needle, another should light the generator warning light. I have a feeling the D+ terminal may be the exciter connection, and supplying this pin with +12v through the resistance of the warning light bulb, should get the alternator charging.
Memory is fading but I think there are 2 lights on the console, one is a generator light, the other is a battery symbol. As set up right now, the battery light flashes when the ignition is surend on, and an alarm sounds after a few seconds.

 

[VicS]

You may find the alternator section on this site helpful.

http://www.tb-training.co.uk/cover.html

The table under the heading " wiring the alternator" I think will identify the alternator terminals but you will then have to identify the wires that go on them.

 

[dalex]

Thanks for the very useful site. The first place I have even seen the D+ terminal mentioned anywhere!
I'll try applying this, and let you know.
Many thanks.

 

[Andrew_Fanner]

The alternator is probably a Paris Rhone one, given what is on my 41, further trawling around Guru Brooks' site should expose a diagram of equivalents between 61, D, W and so forth. If you are still struggling by Friday PM me, I'm off to the boat on Saturday and have the relevant wiring diagram somewhere on board which could be scanned and emailed.

 

[VicS]

A little more info which might help and hopefully not confuse:

From an old Volvo ws manual. For Bosch or SEV alternators with external regulators

<ul type="square"> [*]B+ on the alternator to battery + [*]61 on the alternator to D+ on the regulator and the warning light [*]F on the alternator to DF on the regulator (this is the field current) [*]E on the alternator to earth and D- on the regulator [/list]

 

[dalex]

Hi,
Couldn't find any Guru Brooks' site on google.. you wouldn't happen to have a url would you please?
I had a chat with the guy who mends Volvo alternators. He told me the following info, which I have yet to try out.
B- is Negative return. This is typically strapped to the engine block.
B+ is Battery plus.
W terminal is to the rev counter, and is a tapping off the a/c side, before the rectifiers.
D+ is, wait for it, the warning light!!! I was told that if the warning light bulb blows, the alternator WILL NOT CHARGE.
To identify the warning light wire, he suggested strapping the wire to ground, to see if it will light. If none of the wires thusly strapped (apart from the obvious thick red ones of course!!) illuminate the bulb, then this is dead Jim. Change the bulb, and repeat. The one unstrapped from ground that makes the bulb go out, is the warning light. Hmmm, W does not = warning light. W = a/c tap. D+ = warnign light. Logical?
Anyway I'll give it a try tomorrow, and see if this works!

 

[dalex]

Thanks for this, but I think my alternator is a bit later than these, having an internal regulator. But if the 61 pin goes to D+ on an external reg and then to the warning light, that lines up with Mr Alternaor man's advice, so some hope there!

From what I have read, this alternator is capable of operating in either P or N mode, and can do something called battery sensing. I understand this is important where the alternator charges multiple sets of batteries using a blocking diode, and boosts the alternator output to overcome the volt drop on the blocking diode.
The upshot of this is you get 14.4 volts at the leisure battery bank as the alternator output gets lifted to a tad over 15v.
I don't have a blocking diode, but this sounds like both a clever idea, and a yet more complication. I might think about doing this when I got a basic charge coming out of the *$%£ard thing....

 

[Andrew_Fanner]

Its the TB training one. The chap who does it has been known to post here at times. You would do best to look at this bit.

Alternators

and this bit, scroll down to find a picture of the connections on a Paris Rhone alternator.

Alternator diagram

The main charge wires will be more substantial and, based on my experience, will be ring terminals as opposed to spade ones. Note that spades may have been fitted onto smaller teminal posts for the auxilliary connections. You may have rubber insulation caps on the cable that fit over the nust that fasten the rings to the alternator terminals.

Depending on the exact setup and auxilliary connections don't forget that the laternator may need to spinn up to >1000 revs to excite the coils enough to start charging, you can then back off a bit and still get some output.

Do check the charge light, as stated, if it has failed you may well get no charge at all. An electrician _may_ have put a resistance in series with the bulb which will allow charging to continue, but unless you know this to be the case assume not.

Keep us posted.

 

[VicS]

[ QUOTE ]
Do check the charge light, as stated, if it has failed you may well get no charge at all. An electrician _may_ have put a resistance in series with the bulb which will allow charging to continue, but unless you know this to be the case assume not

[/ QUOTE ] I think you meant to say a resistance in parallel with the bulb

 

[Andrew_Fanner]

D'oh, yup

 

[phaseloc]

Volvo Penta alternator Replacement Question

Dear sirs, I have read your feedback regarding the gentelman's question regarding the alternator rewiring and it appears you may have information which might assist me with my problem.

I have just recently replaced my Valeo alternator with a high output, externally regulated alternator which is with out a D+ terminal. Therefore my warning lights do not fuction correctly. I have tested the #61 lead from the engine electroncis and it appears to be happy when the #61 terminal is grounded w/ the ignition on (engine not running), and w/ the engine running #61 connected to the positive output of the alternator.

Do any of you know of a solution for this problem?

My tachometer also reads approximately 40% higher than it should, do you have any recomendations on resolving that?

FYI, my engine is a 1996 MD22P.

Thank you.