RichardH
AKA The Mad Hat Man
Calling all yo automotive electricians.
I have a basic understanding of how an alternator works...... Voltage supplied via Warning lamp which energises the system. The alternator induces an AC voltage which is rectified and compared to the supplied voltage, but at an increased current. This is supplied back to the battery to charge it.
I have a weird problem with my '40.
I have had the Alternator tested and it is "fine".....
However........
On initial turning of ignition key, the "Alt" warning lamp is lit.
As soon as the engine fires up, the warning lamp goes out, but the Alternator does not seem to charge.
When the engine is turned off, the "Alt" light does not come on - repeated turning of the ignition key does not induce the light to come back on.
If the car is left several days, the "Alt" light comes back on until the engine is started.
I have checked the electrics today....
There is power to the warning lamp at all times.
The warning lamp bulb is OK.
Earthing of the energising wire to the alternator, turns the warning lamp on.
The engine and the Alternator body are both grounded to "earth".
This seems to me like the energiser part of the alternator is faulty and is leaving a back EMF on the energiser wire, thereby putting out the warning lamp, but not energising the Alternator to produce any current.
How could the Alternator have tested "OK"?
Any ideas as to what could be causing this?
Any tests I can carry out in-situ, bearing in mind where the Alternator is mounted on a '40 (OS front of engine)?
The Alternator is similar to a Delco LRA177 or a DRA3457, but to be honest, I am not exactly sure what it is.:huh:
I have a basic understanding of how an alternator works...... Voltage supplied via Warning lamp which energises the system. The alternator induces an AC voltage which is rectified and compared to the supplied voltage, but at an increased current. This is supplied back to the battery to charge it.
I have a weird problem with my '40.
I have had the Alternator tested and it is "fine".....
However........
On initial turning of ignition key, the "Alt" warning lamp is lit.
As soon as the engine fires up, the warning lamp goes out, but the Alternator does not seem to charge.
When the engine is turned off, the "Alt" light does not come on - repeated turning of the ignition key does not induce the light to come back on.
If the car is left several days, the "Alt" light comes back on until the engine is started.
I have checked the electrics today....
There is power to the warning lamp at all times.
The warning lamp bulb is OK.
Earthing of the energising wire to the alternator, turns the warning lamp on.
The engine and the Alternator body are both grounded to "earth".
This seems to me like the energiser part of the alternator is faulty and is leaving a back EMF on the energiser wire, thereby putting out the warning lamp, but not energising the Alternator to produce any current.
How could the Alternator have tested "OK"?
Any ideas as to what could be causing this?
Any tests I can carry out in-situ, bearing in mind where the Alternator is mounted on a '40 (OS front of engine)?
The Alternator is similar to a Delco LRA177 or a DRA3457, but to be honest, I am not exactly sure what it is.:huh: