gavbriggs said:

ha!!!

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Looking at some of your posts, I've always reckoned you to be a bit of a smarty pants totaly wasted as a chromium smelter No I'm not being sarcastic

Datatek said:

Looking at some of your posts, I've always reckoned you to be a bit of a smarty pants totaly wasted as a chromium smelter No I'm not being sarcastic

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i see you also do your homework too!!! so thats air, leccy and nosey neighbouring!!!

chromium is what i do for cash, fecking with cars and everything else is what keeps me sane!!

if i didnt have to work i'd be a full time fecker abouter!!!:doh::doh::doh::doh:

my bad - its not AC ripple Voltage - but current!

so whats the current got to do with it then?

this mite help ya.....


ALTERNATOR TESTING
The voltage regulator will generally vary charging voltage from about 13.8 volts on warm days to about 14.8 volts on sub-zero days. At room temperature, an alternator should charge about 14.2 volts.

Keep in mind that, while most modern alternators produce nearly 100 amps at idle speed, amperage output is generally rated at 2,500 rpm engine speed. When measured as close to the alternator B+ terminal as possible, the amperage output of the alternator should meet specifications. If the alternator drive belt squeals approaching maximum output, the alternator drive belt and pulley should be inspected for glazing and wear. If the amperage output doesn’t meet specifications, suspect an open diode or worn brushes.

Many carbon pile testers have an “AC ripple” feature indicating when a shorted diode is “leaking” alternating current into the charging system. The diode test can also be performed by setting a digital volt-ohm meter to AC voltage and attaching the positive lead directly to the alternator B+ terminal. In general, AC voltage shouldn’t exceed a maximum of 0.250 AC volts. A reading of 0.8 to 1.0 AC volts is normal. Keep in mind that excessive AC ripple can cause performance issues in the PCM and related modules.

so putting a load on it then measuring the voltage would indicate a problem, but its best done at 2500 revs?

gavbriggs said:

so putting a load on it then measuring the voltage would indicate a problem, but its best done at 2500 revs?

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So it would appear - am still checking .

i wondered if my mates cv and all his quals for motor mechs was genuine, turns out they could well be!!!

and if you think i'm a smarty pants, you should hear him. can hold a convo on just about anything, and upon checking his statements found to be true!!!

Here is a copy of a Denso alternator specn.

not sure wot AC ripple means tho - 4 whats (sic!)

it'll be per revolution !!!

This mite help anorl...

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oops!

try this

gavbriggs said:

i see you also do your homework too!!! so thats air, leccy and nosey neighbouring!!!

chromium is what i do for cash, fecking with cars and everything else is what keeps me sane!!

if i didnt have to work i'd be a full time fecker abouter!!!:doh::doh::doh::doh:

Click to expand...

For what it's worth, I have played with motorbikes and cars all my life, spent all my spare cash building racers which is where my limited knowledge of cars comes from. Also used to earn extra cash by repairing Volvo electronic modules like dash panels, fuel pump relays and the like for a local Volvo indy. All very useful experience for the P38 where all the parts seem to have a very short service life.

The Mad Hat Man said:

my bad - its not AC ripple Voltage - but current!

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Unless I have forgotten Ohms law, for there to be current ripple there would also have to be voltage ripple since V over R = I where V is the regulated voltage output of the alternator and R is primarily the internal resistance of the battery which is relatively constant for a given state of charge, so for the current to ripple, one other parameter must change and that is usually the voltage often caused by a duff regulator or worn brushes.

You are very unlikely to measure the full 100 amp output of the alternator for more than a few seconds except on a test rig because as the battery voltage rises towards the alternator regulated voltage the current drops rapidly. Might do it with everything switched on I suppose.

@chrispiec

bet you're glad you asked, huh?

Datatek said:

Unless I have forgotten Ohms law, for there to be current ripple there would also have to be voltage ripple since V over R = I where V is the regulated voltage output of the alternator and R is primarily the internal resistance of the battery which is relatively constant for a given state of charge, so for the current to ripple, one other parameter must change and that is usually the voltage often caused by a duff regulator or worn brushes.

You are very unlikely to measure the full 100 amp output of the alternator for more than a few seconds except on a test rig because as the battery voltage rises towards the alternator regulated voltage the current drops rapidly. Might do it with everything switched on I suppose.

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yeah i know!