Club 80-90 Forums

bigherb wrote: And never run an alternator with the battery disconnected the diodes don't like it.

didnt know that, glad it wasnt my idea

Alternator is nothing more than a dynamo or a electric generator.
disconnecting it will not damage anything.

kevtherev wrote:Alternator is nothing more than a dynamo or a electric generator.
disconnecting it will not damage anything.

Id be surprised too but some opinions here i found ( although they are not fact just comments)
https://grassrootsmotorsports.com/forum ... 092/page1/" onclick="window.open(this.href);return false;

This was interesting


iceracer SuperDorkOct. 22, 2011 3:01 p.m.

It is one of those things that maybe it will, maybe it won;t. Why take the chance when voltmeters are so cheap. Alernators are not. if the alternator were operated without load or battery the voltage would rise linearly with the speed of the alternator. Posibly rising to as high as 140 v. Paraphraised from my Bosch book.

kevtherev wrote:Alternator is nothing more than a dynamo or a electric generator.
disconnecting it will not damage anything.

Then I'm sure you will guarantee to buy him a new one if it does.

Si_P wrote:

bigherb wrote:Yes alternators can run over 70 deg

As bizarre as this may sound that information has restored a little hope in me.

After a long line of 'issues' I thought this would be another nail biter.

I'll run some more checks (with a more car savvy mate) with any luck we will get the all clear.

Thank you all for your help so far.

First check the batt voltage, if its low charge the battery for as long as you can then retry
could also pull the belt off and check it spins freely, just because its new doesnt mean its not faulty and i suppose pulleys were swapped so check they are tight or keyed with a woodruff key

itchyfeet wrote: if the alternator were operated without load or battery the voltage would rise linearly with the speed of the alternator. Posibly rising to as high as 140 v. Paraphraised from my Bosch book.

Your on the right track.
Silcon semiconductors only have a safe maximum voltage they can work at. Rectifier diodes are a one way valve if the voltage is too high the diode will break down allowing current to pass both ways causing a short circuit. Most times you will get away with it but it only needs one weak semiconductor to commit silicon suicide to ruin the alternator.

Whatever..
synthetic and mineral oil type debate
removing the battery from the equation for a short time to diagnose a fault is safe enough for me.

It is getting hot very quickly, it should be noted that the battery is flat due to the previous alternator not doing the job.

is the reason for its hot operating temp, which I'm sure is the real world answer

Would have thought if 12v feed is disconnected the alternator won't charge anyway, therefore no regulator/rectifier damage.
Only other thought is belt tension, make sure not too tight, alt will run hot if belt b@st@rd tight.

Also if the belt is sliping the friction will make the pulley very hot!

Once again thanks for the help.

A new belt will be fitted this afternoon and the battery has been removed and put on charge so fingers crossed....

To every one,

With a new belt and a fully charged battery all is well in my vanhold.

Thanks a million to you all for your advice during my moment of pure stress; I have learnt things I did not know I needed to learn.

Club 80 90 is a wonderful place I would be lost without it.

Regards


Simon

Well done
i think we all learned something
enjoy your holiday