symtoms of blown rectifier in alternator ?

[steveo3002]

yes ive had a a google , usuaally get good answers here too

any pointers if a rectifier is blown in a car alternator ? charge is staying at a steady 14v what else can i look at

 

[voipio]

Surely if a rectifier is blown, it wouldn't charge, or are you suspecting only one diode, of several, has gone? Are there any other symptoms e.g. squealing belt, overheating of the rectifier, a laboured idle sound to the engine? The actual symptoms would depend on the type of failure. Looking at the ripple on the battery, using an oscilloscope, might tell you if a single diode is malfunctioning.

 

[steveo3002]

another owner suggested its what damaged his ecu

alternator charges fine , no noise /heat /funny buisness

 

[julianthegypsy]

Unless things have changed in ways I can't comprehend, your rectifier is working. One blown diode stops it working and there would be 0 volts, not 14 volts.

 

[steveo3002]

youtube suggests ....multimeter diode test to check diode working , then meter accross battery on ac setting ..should be no more than 0.5v ac ?

 

[johnik]

as above, if one diode dies, it will still charge but it puts extra current through the remaining ones, they wil die and it,s game over. the alternator produces AC the rectifier turns that into DC so it can charge the battery

 

[The_Yellow_Ardvark]

What makes you think the alternator has an issue?

 

[steveo3002]

What makes you think the alternator has an issue?

ecu had damage , unknown why ....another owner stated his alternator was to blame for the same fault

wanted to check over anything obvious incase i ruin the replacement

 

[MoreWellie]

any pointers if a rectifier is blown in a car alternator

I had a blown pack when the battery had accidently disconnected and I realised that I had a fault when the ignition/charge light started flickering on at idle

 

[RichardM]

What's doing the voltage regulation? You say the charge is staying at 14v is that throughout the rev-range?

 

[m_c]

ecu had damage , unknown why ....another owner stated his alternator was to blame for the same fault

wanted to check over anything obvious incase i ruin the replacement

Somebody you actually know, or some random on the internet?

The chances of an alternator fault damaging a vehicle ECU are pretty remote. Anything built to the required automotive standard should handle any kind of fault an alternator is likely to produce.
There is far better chance said owner done something stupid like connecting jump leads the wrong way around, than the alternator causing just an ECU to fail without any other noticeable problems.

 

[steveo3002]

What's doing the voltage regulation? You say the charge is staying at 14v is that throughout the rev-range?

alternator has a built in reg , yeah stays around 14v , no crazy spikes or drops

and m_c yeah a internet random lol