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  #11  
Old 01-Jun-2005, 13:37
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JPM JPM is offline
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If the alternator nut was loose it would run badly pretty much all of the time not just when the lights were turned on. I would check the casing on the l/h side and see if there's new sealant on there which would indicate that it's been removed and probably tightened though, or ask the dealer(s) who serviced it
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  #12  
Old 01-Jun-2005, 15:03
Lust4Life Lust4Life is offline
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Yep, failed R/R according to the tests.

The generator/stator appears to be fine which is good news.

I've just ordered an R/R from Electrex after speaking to Miranda and I'd like to say their customer service is excellent.

Out of interest, a Ducati R/R is £136 and 2-3 days wait and the Electrex is available next day by special delivery for £75 so it's not a difficult choice.

The customer service from Ducati Ashford was very pleasant as well though.

Many thanks to all who helped!

Phil
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  #13  
Old 01-Jun-2005, 15:28
Felix Felix is offline
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Mood: Is 112 dB loud enough?? What??
Do fit the later style heat sink plate, though.
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  #14  
Old 01-Jun-2005, 18:41
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There's a high current involved here so you need to run separate ground wire from the regulator in its new location back to the battery terminal. If you grounded to the frame locally, that's your problem. Any regulator normally runs too hot to touch which is why you should place it out in the airstream.

The under-the-seat location might be better than inside the fairing but I recommend the backside of the license plate holder. Under the seat has poor heat convection and conduction cooling (unless you use a heatsink bolted to something cooled by the airflow.) The "heatsink" plate added to later bikes is there primarily to reflect exhaust pipe heat away from the regulator and help direct airflow from the fairing duct. It won't help much under the seat.

The charging voltage will be different for different batteries. Mine typically runs around 13.6 at speed. If the battery terminal voltage is higher with the lights on at 3500 rpm than the voltage at key-off, you're charging OK.


http://ducatisportingclub.com/contro...d.php?tid=2042
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  #15  
Old 02-Jun-2005, 00:27
Lust4Life Lust4Life is offline
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Nice one, good idea to take the earth back to the battery.

My new Electrex R/R should be here Friday so I can get cracking.

Is there any issue with riding in the wet if I mount the R/R on the inside of the license plate holder?

I don't actually ride in the rain deliberately but could get caught out.

Many thanks!

Phil
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  #16  
Old 02-Jun-2005, 01:14
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The RR51 electronics are encapsulated in epoxy so it's waterproofed, but I suppose adding a little silicone sealant where the wires exit the regulator casing wouldn't hurt.
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  #17  
Old 02-Jun-2005, 01:58
Felix Felix is offline
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Mood: Is 112 dB loud enough?? What??
There is no way I would mount the regulator that far away from the battery. For good reason you want to keep the wires as short as possible. But hey, to each their own.
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  #18  
Old 02-Jun-2005, 02:22
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When you relocate your regulator to behind the license plate, the stator wires are routed outside (the hot environment inside the fairing.) and you use a larger AWG 12 gauge wire to compensate for the somewhat longer length and electrical heating due to the high current being carried.

The main issue with replacing the stator wires is to reduce the electrical heating from the 30+ amp current they have to carry. A different aspect of this is that any in-line connector becomes a hot spot because, as corrosion occurs, that causes the connector resistance to increase and the heat generated to increase in this region. This damages the connector (melts the plastic ones) and overheats a few inches of wire both sides of the connector.

But that’s not the whole issue. Any wire, no matter what size, has resistance (so many ohms per foot) so any wire will heat up. Obviously the larger the wire gauge, the less resistance it will have to current flow, and the less heating that will occur for a given current.

The type of insulation on the wire is also important to this discussion. Different materials have different temperature allowables for continuous operation. For example for 10 gauge (AWG) wire in 30ºC (86ºF) free air:

55A will heat high density polypropylene to 90ºC allowable
58A will heat Polyvinyl Chloride (PVC) insulation to 105ºC allowable
75A will heat Kapton, Teflon, and Silicone insulation to 200ºC allowable

So for example, silicone insulated wire should be used for higher current ratings or for hotter operating environments.

The environment that the wire sees is very important, and this is where Ducati engineers screwed-up. The above temperature ratings assume that the wires are located in 30ºC free air. The stator wires run first internally to the engine, and then are enclosed on a sheath that passes over the engine and internal to the fairing. So the insulation on these wires don’t see adequate cooling, they exceed their performance rating, and loose their insulation properties.

The portion of the stator wiring that run in the sheath is where insulation failure is critical. The stator wire are held closely together and insulation breakdown from heat causes them to short together at the higher output voltages at higher engine rpm.

The Haynes Manual, Section 9.21 has this warning:

Caution: Never disconnect/connect (i.e. short together) the alternator wiring with the engine running as this will damage the regulator/rectifier.

Most regulators fail because they get too hot inside the fairing, but this intermittent shorting together of the stator wires is the other cause of regulator failures.

The wires inside the engine don’t come in contact with each other until they exit the cover. Even if the insulation overheats it can’t damage the regulator, and because of the hot environment, a larger gauge wire inside the cover isn’t going to reduce insulation operational temperatures much in this section of wire.

The leads attached to the regulator/rectifier are a smaller gauge but they also see a cooler environment than the sheathed wires. Sure, they’ll be heated more than the larger gauge replacement wires but they have better cooling. So, just make a low resistance splice to the RR wires.

On my 916, I relocated the RR so that the stator wires now quickly exit the fairing, run along the frame (good conduction and convection cooling) and since the regulator is outside the fairing it runs much cooler. So this situation allowed me to run a only slightly-larger 12 gauge (SWG 14 gauge) PVC coated replacement wire between the stator cover and the regulator splice.
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  #19  
Old 02-Jun-2005, 12:17
Lust4Life Lust4Life is offline
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Excellent service from Electrex, my R/R arrived this morning even though I only ordered it yesterday afternoon.

I'll be off shortly to pick up some decent wire and I'll try the license plate location initially I think.

Many thanks to all who helped.

Phil
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  #20  
Old 02-Jun-2005, 22:16
Lust4Life Lust4Life is offline
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All fitted now and charging perfectly.

Went with the original location in the end (couldn't get decent cable) and made an ally heatshield up which is isolated from the R/R.

Nice to know I can have my lights on now!

Cheers!

Phil
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