Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: Have I killed it?
ste

posted on 10/1/19 at 04:36 PM Reply With Quote
Have I killed it?

So, I funked up a bit. I forgot to fit an earth between engine and chassis on the Dax I'm building. I am in the middle of wiring the thing up and was doing a bit of testing. Engine turned over just fine. Took the exhaust off to fit the lambda sensor and soon noticed the charge light lit when ignition was off and then it went off with ignition on, tried to turn the engine over and nothing!
Turns out, the engine was earthing through the exhaust.

After a bit of head scratching, figured out it wasn't earthed and made a lead.

Connected everything back up and all seemed fine.

But after about half an hour, i touched the alternator and it was hot.

Tested the current draw and it was pulling 36mA from the battery.

Disconnected the plug on the alternator and it cooled down.

Have i killed it?

I think it is a small Daihatsu/Nippon Denso Alternator

View User's Profile View All Posts By User U2U Member
ste

posted on 10/1/19 at 04:42 PM Reply With Quote
Click for pic
View User's Profile View All Posts By User U2U Member
theconrodkid

posted on 10/1/19 at 05:02 PM Reply With Quote
if it was hot then yes it is toasted, electrickery will try to find a way back home, no earth lead and it will follow throttle cable or anything else where live meets earth...ie inside the alternator.





who cares who wins
pass the pork pies

View User's Profile E-Mail User View All Posts By User U2U Member   theconrodkid 's Aim   theconrodkid 's Yahoo
gremlin1234

posted on 10/1/19 at 05:06 PM Reply With Quote
36mA at 12V is 0.036x12 = 0.43W, which I wouldn't expect to noticeably warm (certainly not hot) an alternator
View User's Profile View All Posts By User U2U Member
ste

posted on 10/1/19 at 05:15 PM Reply With Quote
quote:
Originally posted by gremlin1234
36mA at 12V is 0.036x12 = 0.43W, which I wouldn't expect to noticeably warm (certainly not hot) an alternator


It wasn't hot in the normal sense of the word, but compared to everything else in my garage at about 5 degrees it was quite warm at 40 degrees C

View User's Profile View All Posts By User U2U Member
gremlin1234

posted on 10/1/19 at 05:39 PM Reply With Quote
quote:
Originally posted by ste
quote:
Originally posted by gremlin1234
36mA at 12V is 0.036x12 = 0.43W, which I wouldn't expect to noticeably warm (certainly not hot) an alternator


It wasn't hot in the normal sense of the word, but compared to everything else in my garage at about 5 degrees it was quite warm at 40 degrees C

how did you measure the 36mA? because that is only about a quarter of what the panel light itself would normally take. I would believe it feeling warm if it were 10 times that, (4W )
also from the picture the alternator earth path looks like its trying to earth though a loosely fitted, powder-coated bracket.
bolt it all together, and measure current again. (it might just sort itself out)

View User's Profile View All Posts By User U2U Member
Mr Whippy

posted on 11/1/19 at 12:55 PM Reply With Quote
ditto you can't heat up an alternator on 36mA!
View User's Profile Visit User's Homepage View All Posts By User U2U Member   Mr+Whippy 's Aim
adithorp

posted on 11/1/19 at 01:28 PM Reply With Quote
Was this after 1/2hr running or stopped. If the latter (which I read it as) then it's knackered. If its the first then you might be ok. What's the voltage when running like?





"A witty saying proves nothing" Voltaire

http://jpsc.org.uk/forum/

View User's Profile View All Posts By User U2U Member
MikeRJ

posted on 11/1/19 at 02:46 PM Reply With Quote
quote:
Originally posted by gremlin1234
36mA at 12V is 0.036x12 = 0.43W, which I wouldn't expect to noticeably warm (certainly not hot) an alternator


Agreed. 36mA leakage is too much for a healthy alternator, but nowhere near enough to noticeably warm it up. Perhaps the OP misread 3.6 Amps, which would get it hot.

View User's Profile View All Posts By User U2U Member
ste

posted on 11/1/19 at 02:46 PM Reply With Quote
quote:
Originally posted by adithorp
Was this after 1/2hr running or stopped. If the latter (which I read it as) then it's knackered. If its the first then you might be ok. What's the voltage when running like?


It doesn't run yet, this was just trying to crank the engine over.

It's coming off and going to a local alternator specialist to be tested and repaired. Lesson learned!!

View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [ 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.