Alternator query #2

[julians]

I've replaced the alternator that failed with a new one, however the new one is not working either.

 

The problem sees to be that it is not getting enough volts/current at the field terminal, hence the coil is not magnetising hence no charging voltage is being produced.

 

If I connect a wire direct from the battery to the field terminal, it all works fine, so this lead me to think that the field wire isnt supplying enough volts. I measured the voltage at the field terminal, this is only getting 1.45 volts. I presume that the alternator needs the full 12v at the field for the coil to energise (can any one confirm what the field voltage needs to be?).

 

The battery warning light lights up when the ignition is switched on, so it isnt this bulb which has broken, could it be that my new alternator requires a different field voltage compared to the old alternator, or is the field voltage generally the same on all alternators.

 

Anyone got any suggestions. I'll be checking all the connections from the warning bulb to the field terminal tonight.