Alternator

[Sir Nibble]

You could improve matters by gearing up and getting better cooling. Symptoms are classic for a failed diode and the heavy duty rectifier doesn't seem to still be available.

[roland elsdon]

Thanks for suggestions and ideas.

probably correct re more cooling as I think diodes are cooking off. That certainly happened last time 2 years ago when the last one failed, it popped just after the adverc went over to 14.4 on low batteries with a heavy load on. Took out the adverc too.

cant add gizmos to engine room it's very 1960s minimal and all electrics are hidden. Might gear up for more cooling but of course could just go faster....

[davidg]

16 hours ago, roland elsdon said:

Clockwise rotation mounted on left . Standard lister hb. Standard pulley sizes. It's not overworked. I think it's a quality issue. Just wondering if paying 3 times more will give me 6 yrs service before I swap in the blown spare...

Roland, if it's a standard H series Lister the rotation will be anti clock looking at the flywheel end and as I said earlier, five gets you ten the A127 has a clockwise fan on it. The alternator won't cool as well as it should. Take a look and I'll have my five next time I see you.

David

[mango]

16 hours ago, cereal tiller said:

No link needed,the Temperature controllers are  easily available from sources such as ebay,just ask for 12 volt digital panel mounted Temperature Controller,will come complete  with probe on a1 Meter cable,if you go ahead with the modification feel free to P.M me for installation details,the mod to the Alternator Field wire is simple and Quick,no dismantling required.

CT

Thanks CT.  I was thinking that this must have been covered in another thread.  I don't have a boat but will certainly pass on the suggestion next time I encounter an alternator hot enough to fry eggs.  Over the years I've had plenty of fun with alternators on boats, including ones that have broken their mountings.

[cereal tiller]

2 hours ago, mango said:

Thanks CT.  I was thinking that this must have been covered in another thread.  I don't have a boat but will certainly pass on the suggestion next time I encounter an alternator hot enough to fry eggs.  Over the years I've had plenty of fun with alternators on boats, including ones that have broken their mountings.

You are welcome,the A127 seems happy to deliver 45 Amps. or so without getting "Hot under the  Collar /Stator"so to speak.

The Engine pair spin at over 6000 R.P.M. when the Boat is at Upper Thames cruising speed(Approx. 5 M.P.H.)

If the Alts. are rotating at 4-5000 R.P.M. the Fans do not appear to remove heat as well as they would at higher speeds.

So, if the Battery bank is depleted after the Boat  has stood for a Day or two,both 75 A.MP. Alternators run at full output for a considerable period,that is when the Temp. Controllers come into play,cutting off the charge and allowing them to cool for a minute or two.

When charging recommences the load on the V Belts is not excessive as the Rotors are still spinning.

CT

 

Edited May 20, 2017 by cereal tiller