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[Amel Yacht Owners] Re: Alternator and Masse leak detector
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Hi Nick,
Another possibility (and I completely forgot about this until I was reminded by a friend) is the little red light at the bottom left of the 24VDC panel. If your 24VDC alternator has the standard automotive type internal regulator then this lamp is what provides the excitation current. If everything is working normally, when you turn the key on, this lamp should light. When you start the engine and the alternator is spinning, this lamp should go out. Have someone watch this lamp when you turn the key on and then start the engine. If the lamp doesn't light at startup this could be your problem...blown lamp or bad connection somewhere. BTW the reason I forgot about it is that our little red lamp is disconnected as we have an external 3 stage regulator connected to the 175A Leece Neville 24VDC alternator (the internal regulator is disconnected) in order to charge (and more importantly not overcharge) the house batteries in a proper manner. Good Luck Alan Elyse SM437
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Alexandre Uster von Baar
Was the same on NIKIMAT SM2K #289 (and on a 1976 Aston Martin I owned).
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Sincerely, Alexandre --------------------------------------------
On Mon, 6/18/18, John Clark john.biohead@gmail.com [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote:
Subject: Re: [Amel Yacht Owners] Re: Alternator and Masse leak detector To: amelyachtowners@yahoogroups.com Date: Monday, June 18, 2018, 11:30 AM My SM#37, with Volvo TMD22 requires a rev for tach and 12v alternator to fire off. Not sure if it is right but it has been stable for last year. John Clark SV Annie SM37enroute to St. Lucia. On Mon, Jun 18, 2018, 9:46 AM greatketch@yahoo.com [amelyachtowners] <amelyachtowners@yahoogroups.com> wrote: Nick, There are no "partial failures" of diodes. As solid state devices they either work--or not. When they fail they fail "open" and block current flow in both directions. It is possible, I guess, you could have a short circuit inside the alternator somewhere, but the chances of it working at all would then be pretty close to zero. Bill KinneySM160, HarmonieAnnapolis, MD, USA ---In amelyachtowners@yahoogroups.com, <kwzy6vgkpvtfohjddjsrotobzwf2pjeafjwalhur@...> wrote : Hello fellow Amelians, I have had a great passage to the Azores from Antigua (14.5 days). Some months ago I asked the forum about exciting the 24v alternator and was advised by Bill to check the relay and excitation circuit which I did. However I still have the same problem that the alternator needs 1500 rpm to "kick in". Once kicked in I can throttle back idle and still charge. No big deal right.....well yes and no I am beginning to think that maybe one of the diodes is defective and that I might have a small current drain through the alternator. Does anyone know if a diode failure is compatible with the general history I have described? Why am I thinking along these lines? I had to return to the UK for two weeks, so when I left the boat last week I checked the "Masse" leak indicator that came up with a leak on the -ve side. Unfortunately I had to catch my plane so I only turned off the master red handles for the batteries. Thinking that the batteries would be isolated. Now back in the UK, unable to check the boat I am worrying. If I am correct, the red handles do not isolate the chargers or the 24v alternator from the battery bank. Thus if there is a diode failure on the 24v alternator the batteries could be leaking despite the red handles being turned off. This could be bad for my anodes and prop for example not to mention the battery bank. Does anyone know if the red handles isolate the 24v Alternator or not. I can not remember 100% but I believe not as when I was working on the engine one time I turned off the handles only to discover the cables to all be still live. To summarise what my questions are:1. Is the excitation history, i.e. reving to 1500 etc on the 24v alternator compatible with partial diode failure?2. Do the red handles shut off everything? 3. Could a -ve leak as detected by the masse be compatible with diode failure? NickAmelia (amel 54 hull 019)
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Patrick McAneny
Since several boats are the same , in that they need to rev up to charge, maybe someone could chime in and say if this normal or not.
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Pat
SM#123
-----Original Message----- From: Alexandre Uster von Baar uster@... [amelyachtowners] To: amelyachtowners Sent: Mon, Jun 18, 2018 4:20 pm Subject: Re: [Amel Yacht Owners] Re: Alternator and Masse leak detector Was the same on NIKIMAT SM2K #289 (and on a 1976 Aston Martin I owned).
Sincerely, Alexandre -------------------------------------------- On Mon, 6/18/18, John Clark john.biohead@... [amelyachtowners] <amelyachtowners@...> wrote: Subject: Re: [Amel Yacht Owners] Re: Alternator and Masse leak detector To: amelyachtowners@... Date: Monday, June 18, 2018, 11:30 AM My SM#37, with Volvo TMD22 requires a rev for tach and 12v alternator to fire off. Not sure if it is right but it has been stable for last year. John Clark SV Annie SM37enroute to St. Lucia. On Mon, Jun 18, 2018, 9:46 AM greatketch@... [amelyachtowners] <amelyachtowners@...> wrote: Nick, There are no "partial failures" of diodes. As solid state devices they either work--or not. When they fail they fail "open" and block current flow in both directions. It is possible, I guess, you could have a short circuit inside the alternator somewhere, but the chances of it working at all would then be pretty close to zero. Bill KinneySM160, HarmonieAnnapolis, MD, USA ---In amelyachtowners@..., wrote : Hello fellow Amelians, I have had a great passage to the Azores from Antigua (14.5 days). Some months ago I asked the forum about exciting the 24v alternator and was advised by Bill to check the relay and excitation circuit which I did. However I still have the same problem that the alternator needs 1500 rpm to "kick in". Once kicked in I can throttle back idle and still charge. No big deal right.....well yes and no I am beginning to think that maybe one of the diodes is defective and that I might have a small current drain through the alternator. Does anyone know if a diode failure is compatible with the general history I have described? Why am I thinking along these lines? I had to return to the UK for two weeks, so when I left the boat last week I checked the "Masse" leak indicator that came up with a leak on the -ve side. Unfortunately I had to catch my plane so I only turned off the master red handles for the batteries. Thinking that the batteries would be isolated. Now back in the UK, unable to check the boat I am worrying. If I am correct, the red handles do not isolate the chargers or the 24v alternator from the battery bank. Thus if there is a diode failure on the 24v alternator the batteries could be leaking despite the red handles being turned off. This could be bad for my anodes and prop for example not to mention the battery bank. Does anyone know if the red handles isolate the 24v Alternator or not. I can not remember 100% but I believe not as when I was working on the engine one time I turned off the handles only to discover the cables to all be still live. To summarise what my questions are:1. Is the excitation history, i.e. reving to 1500 etc on the 24v alternator compatible with partial diode failure?2. Do the red handles shut off everything? 3. Could a -ve leak as detected by the masse be compatible with diode failure? NickAmelia (amel 54 hull 019)
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Well on Amelia the Alternator did not need revving up to kick in until a few months ago. So in my opinion it is not correct.
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You can look at the pulley ratio, compare the pulley circumferences of the pulley on the engine v the smaller alt pulley. if it is 2:1 then 900 rpm engine speed equates to 1800 rpm on the alt. Then check the alt specs for output at that rpm. Nick
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Danny and Yvonne SIMMS
Hi Pat. No it is not normal. I have had the same on Ocean pearl and through my rather practical life on other motors in vehicles of diverse types. The excitation circuit is faulty. This circuit feeds voltage to the alternator from the battery. When it is not functioning, as you have found, the alternator self excites if you rev it. On my tmd22 the excitation was activated by tuning the key on and was routed through a voltmeter. (The voltmeter was incedental, it just happend to be in that ciruit and was a handy way to see it was functional) You may have a different circuit but it will be activated by turning the key on. My 24 volt alternator is excited by a feed from the house batteries activated by a solenoid activated by a feed through the start key from the 12 volt starting battery. Search from your key looking for a separated wire or a poor connection. Regards Danny SM 299. Ocean Pearl
On 19 June 2018 at 09:27 "Patrick Mcaneny sailw32@... [amelyachtowners]" <amelyachtowners@...> wrote:
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Patrick McAneny
Danny, OK , good to know, its always been like that and I guess with other things to worry about ,I never gave it much thought.
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Thanks,
Pat
-----Original Message----- From: Danny and Yvonne SIMMS simms@... [amelyachtowners] To: amelyachtowners <amelyachtowners@...> Sent: Mon, Jun 18, 2018 5:45 pm Subject: Re: [Amel Yacht Owners] Re: Alternator and Masse leak detector Hi Pat. No it is not normal. I have had the same on Ocean pearl and through my rather practical life on other motors in vehicles of diverse types. The excitation circuit is faulty. This circuit feeds voltage to the alternator from the battery. When it is not functioning, as you have found, the alternator self excites if you rev it. On my tmd22 the excitation was activated by tuning the key on and was routed through a voltmeter. (The voltmeter was incedental, it just happend to be in that ciruit and was a handy way to see it was functional) You may have a different circuit but it will be activated by turning the key on. My 24 volt alternator is excited by a feed from the house batteries activated by a solenoid activated by a feed through the start key from the 12 volt starting battery.
Search from your key looking for a separated wire or a poor connection.
Regards
Danny
SM 299. Ocean Pearl
On 19 June 2018 at 09:27 "Patr ick Mcaneny sailw32@... [amelyachtowners]" <amelyachtowners@...> wrote:
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Hi Alan,
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Thanks Yes I have checked the belts, no problem there. The rectifier may be at fault, I think. Will have it bench tested. Re -ve light leak coming on at the Masse it will be a long process but I guess starting with the bilge pump, wc motors, Bowthruster, windlasses etc etc. Thanks Nick s/yAmelia
On 18 Jun 2018, at 09:40, divanz620@... [amelyachtowners] <amelyachtowners@...> wrote:
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