Mack Posted May 29 Report Share Posted May 29 Hello all, In an effort to figure out the whine coming from the front of my engine and it potentially being the alternator I thought I would have a poke around. In doing so I could see an unattached red wire starting to poke out of the black plastic cover on the back. Removed said cover and discovered this guy hanging loose. There appears to be the remanants of some solder on where the blue arrow indicates. I imagine this guy is supposed to be attached somewhere so before I get the soldering iron out can anyone shed some light? Cheers, Matt Link to comment Share on other sites More sharing options...
Colin Lindsay Posted May 30 Report Share Posted May 30 Is that Lucas? I don't recognise the layout but a spare connection like that is often for electronic tacho. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 30 Report Share Posted May 30 (edited) its built in radio suppressor ( use of orange wire ) not much use with VHF and DAB but probably was connected to the rectifier output it wont affect the alternator output , pete Edited May 30 by Pete Lewis Link to comment Share on other sites More sharing options...
Mack Posted May 30 Author Report Share Posted May 30 I think it is a lucas 16acr 'type' as I can't see any lucas branding anywhere. Thanks Pete, I just found the exploded diagrams on the moss website for the 16acr and thought it might be that. I will leave it disconnected! Matt Link to comment Share on other sites More sharing options...
johny Posted May 30 Report Share Posted May 30 Probably best if suppression not needed as capacitors can go short circuit😳 Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 30 Report Share Posted May 30 Hi, Is it not an avalanche diode and should it be connected for protection? Cheers, Iain. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 31 Report Share Posted May 31 think the condenser was left as an option you can see the wire has not been connected at any time its just there if you want it a sort of good idea plan but nobody knew about it Pete Link to comment Share on other sites More sharing options...
johny Posted May 31 Report Share Posted May 31 9 hours ago, SpitFire6 said: Hi, Is it not an avalanche diode and should it be connected for protection? Cheers, Iain. Its true there is a protection diode in the WSM diagram (item D) or even the zener diode but neither go to earth as looks to be the case in the photo... Link to comment Share on other sites More sharing options...
GrahamB Posted May 31 Report Share Posted May 31 Item D is a diode to prevent reverse polarisation of the transistor T3 caused by the inductance of the field coil (7). ZD is the zener diode that turns off T3 and so cuts the current to the field coil when the voltage becomes too high. With the Lucas alternator, these components are within the alternator. I would agree with Pete and it is to suppress radio frequency interference and if everything is working correctly, leave it as it is. 1 Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 31 Report Share Posted May 31 Hi all, ZD & D are internal to the regulator. RFI condenser if supplied is externally fitted. The component shown in the picture needs to connect to the "IND"/D terminal. It is to help protect the alternator if the battery or cable comes loose. Failure to connect will cause zero problems or gain anything. But, it can help protect the alternator under fault conditions. I would connect it. Cheers, Iain. Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 31 Report Share Posted May 31 1 hour ago, GrahamB said: Item D is a diode to prevent reverse polarisation of the transistor T3 caused by the inductance of the field coil (7). *****Snip Hi, To "prevent reverse polarisation of the transistor T3" would be better served by inverse connecting a diode across T3 E&C? Cheers, Iain. Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 31 Report Share Posted May 31 Hi, From the Lucas ACR 16-18 Manual: Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 31 Report Share Posted May 31 (edited) Hi, Unable to post ACR manual as too big. Here is a 6 day link: https://we.tl/t-o2BCf0BfcZ It is very interesting. " In an effort to figure out the whine coming from the front of my engine " is covered in the manual. Cheers, Iain. Edited May 31 by SpitFire6 link bad Link to comment Share on other sites More sharing options...
KevinR Posted May 31 Report Share Posted May 31 10 minutes ago, SpitFire6 said: Hi, Unable to post ACR manual as too big. Here is a 6 day link: https://we.tl/t-o2BCf0BfcZ It is very interesting. " In an effort to figure out the whine coming from the front of my engine " is covered in the manual. Cheers, Iain. Iain, Many thanks, no idea why you couldn't upload the file, there isn't a size limit on the Forum for uploads Lucas Manual A1-5.pdf 1 Link to comment Share on other sites More sharing options...
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