blackfish
Well-Known Member
Further to my battery charging issues (on another thread) can anyone tell me the 'must know' gen about the internal charging alternator on this engine?
Thanks in advance.
Thanks in advance.
Bukh DV8 internal charging alternator
- Thread starter blackfish
- Start date
VicS
Well-Known Member
Looks like a stator coil assembly under the flywheel with a 3 phase output to a rectifier/regulator.
Pretty much like many outboards.
Pretty much like many outboards.
blackfish
Well-Known Member
Thanks for that. Looking at the Bukh spares catalogue, it is described as a 'charging alternator 210W'. Any ideas what that refers to. I'm assuming it's a wattage output. Aren't we more interested in amperage? Is there an equivalence relationship between the two?
blackfish
Well-Known Member
Obviously, this kind of information is available (http://www.rapidtables.com/convert/electric/Watt_to_Amp.htm#dc) but I'm not sure whether that's what I'm after (!)
prv
Well-Known Member
Between watts and amps? Um, yes... . Pre-GCSE Physics
Power is current x voltage. So current is power divided by voltage. 210w / 12v = 17.5 amps. At least nominally. The exact figure will depend on the actual voltage (higher than 12v for charging) and how much the batteries will draw at their present state of charge.
Pete
VicS
Well-Known Member
Pete has explained the relationship
You might fnd the Boat electrical course notes at http://www.tb-training.co.uk/ useful in acquiring some basic electrical knowledge.
blackfish
Well-Known Member
Those notes are very helpful. I shall peruse them at my leisure.
blackfish
Well-Known Member
View attachment 57665View attachment 57664
OK Hive Mind, if you can help further I'd be grateful. Went to the boat this afternoon. Both batteries show about 12.6 V on the meter, whether the engine is spinning or not. So, safe to assume that they are not being charged. The Bukh DV8 has an internal stator-type alternator, behind the flywheel. Three wires emerge from the casing behind the flywheel assembly and run to a finned (heat dissipating) contraption bolted to the back of the engine block. Looking at the parts manual, this seems to be what Bukh describe as the charging regulator. The three wires attach to the regulator unit by spade connectors. Out of the top of the regulator a number of wires emerge which are connected to a wiring loom by means of a plug connection. I have included above a photo of my actual set-up and a shot of the Bukh spares manual diagram.
So my questions are these.
Is there any useful information I can glean by using a multimeter on the three 'input' wires? Will that tell me whether the stator alternator is working?
Is there any useful information I can glean from a multimeter on the 'output' wires from the charging regulator?
I am assuming that if they are both working correctly, then my problem lies somewhere further downstream amongst the spaghetti-fest of the wiring.
I don't know whether my photo is reproduced in enough detail here, but a close inspection reveals some hieroglyphics stamped onto the rear of the charging regulator.
Grateful for your time.
PS Just to add insult to injury, I'm pretty certain that, if it were necessary in order to get to the stator, there is insufficient clearance to remove the flywheel (because of its proximity to a bulkhead) without lifting the engine from its mounts! Heigh ho!
OK Hive Mind, if you can help further I'd be grateful. Went to the boat this afternoon. Both batteries show about 12.6 V on the meter, whether the engine is spinning or not. So, safe to assume that they are not being charged. The Bukh DV8 has an internal stator-type alternator, behind the flywheel. Three wires emerge from the casing behind the flywheel assembly and run to a finned (heat dissipating) contraption bolted to the back of the engine block. Looking at the parts manual, this seems to be what Bukh describe as the charging regulator. The three wires attach to the regulator unit by spade connectors. Out of the top of the regulator a number of wires emerge which are connected to a wiring loom by means of a plug connection. I have included above a photo of my actual set-up and a shot of the Bukh spares manual diagram.
So my questions are these.
Is there any useful information I can glean by using a multimeter on the three 'input' wires? Will that tell me whether the stator alternator is working?
Is there any useful information I can glean from a multimeter on the 'output' wires from the charging regulator?
I am assuming that if they are both working correctly, then my problem lies somewhere further downstream amongst the spaghetti-fest of the wiring.
I don't know whether my photo is reproduced in enough detail here, but a close inspection reveals some hieroglyphics stamped onto the rear of the charging regulator.
Grateful for your time.
PS Just to add insult to injury, I'm pretty certain that, if it were necessary in order to get to the stator, there is insufficient clearance to remove the flywheel (because of its proximity to a bulkhead) without lifting the engine from its mounts! Heigh ho!
VicS
Well-Known Member
The three wires coming from the stator coils are the AC. If you can disconnect them from the regulator and check then you should find continuity between all three.
I don't know exactly what to expect but with the engine running you should be able to measure an AC voltage between ony pair
one appears to be differently colour coded ... dont know why.
The other connections will be a negative (but it may be earthed via its mountings) the main positive output which should be a connection, (via the main terminal on the starter motor solenoid) directly to battery positive. One is probably an AC feed for a tacho. One is probably a sensing wire coming from the panel.
Not much help sorry
The only wiring diagram I have found is rubbish...... do you have a decent one ?
blackfish
Well-Known Member
blackfish
Well-Known Member
"one appears to be differently colour coded ... dont know why."
I think that's just the result of a spray paint job sometime. I think that they are all yellow underneath.
I think that's just the result of a spray paint job sometime. I think that they are all yellow underneath.
blackfish
Well-Known Member
"The other connections will be a negative (but it may be earthed via its mountings) the main positive output which should be a connection, (via the main terminal on the starter motor solenoid) directly to battery positive. One is probably an AC feed for a tacho. One is probably a sensing wire coming from the panel."
Just a quick question: why does the positive go via the starter motor solenoid rather than directly to the battery?
Just a quick question: why does the positive go via the starter motor solenoid rather than directly to the battery?
prv
Well-Known Member
Because otherwise you'd need one wire for charging and one for starting. Can be done that way, depending on how you want to arrange your batteries, but manufacturers usually keep things simple and cheap with a single wire.
Pete
VicS
Well-Known Member
As Pete says its just a convenient way or wiring things up. The main heavy + lead from the battery goes to the starter solenoid and that makes a handy nearby place to connect the alternator output.
blackfish
Well-Known Member
Thanks, both.
blackfish
Well-Known Member
View attachment 57702
As you can see, success! The problem was a break in the positive feed from the voltage regulator to the positive terminal on the starter solenoid (as some of you, I think, suspected). Once fixed the house battery showed 13.7 V and the engine battery 14.0 V whist under charge. Nice to know that the 32 year-old stator alternator is still up to scratch.
Many thanks to everybody for the advice.
As you can see, success! The problem was a break in the positive feed from the voltage regulator to the positive terminal on the starter solenoid (as some of you, I think, suspected). Once fixed the house battery showed 13.7 V and the engine battery 14.0 V whist under charge. Nice to know that the 32 year-old stator alternator is still up to scratch.
Many thanks to everybody for the advice.
