QuestionDear Brian,
I've encountered a problem with the charging system in my 1960 Austin-Healey 3000.
For some reason the generator isn't charging the battery. Up till now it has always worked fine.
I've had the car 30 years and this has never happened before.
The regulator is the oldest link in the chain
so I'm replacing that, but I wish to know how I can test the generator to make sure that it's working properly.
I have a 12 volt test light but I'm afraid it will burn out if I connect it to the 2 terminals on the back of the generator.
The battery is new, the fan belt is tight, as are the connections on the regulator and generator.
The generator was rebuilt 2 years ago and I think I polarized it at that time because it's always kept the battery charged up.
The ground straps are all new as is a master battery cut-out switch.
I have an amp gauge in the car and with the engine running above 1200 rpm it always showed a positive charge, until last week.
Now it runs continuosly on the negative side.
Did the regulator finally give up the ghost?
It's about 10+ years old.
Any insight you can supply will be helpful.
Thanks for taking the time to look this over.
Sincerely,
Peter Carbone
You can post this on the web site if needed
AnswerPeter:
First sorry about the delay in my answer. Now then, the questions. Austin Healy 3000 huh? Well, I'm really MG related, but since it's British and in the same vintage, and since most Generator charging systems are basically the same, heck, I'll give it a go!
If you have no voltmeter, the simplest test of a generator is to see if it runs as a motor. First remove the fan belt and the two wires connected to the contacts at the back of the generator. Using a piece of electric wire, make a link wire and then join the 2 terminals and bring a wire from them back toward the fuse block. Touch the wire onto where a Brown wire connects to a fuse (Brown should be battery voltage). There will be a harmless spark and the generator should turn smoothly. If it does not work as a motor, it won't work as a generator either.
To test the generator properly requires a voltmeter. With the fan belt in place, again remove the wires from the back of the Generator and connect a link wire between the its contacts. If your voltmeter automatically selects the voltage range, then switch to V.dc.,if you must also select the range too, switch to one of greater than 20 volts d.c. Connect to the meter between ground and the linked terminals, making sure the + or - go to ground depending on whether the car is positive or negative ground respectively. ( I think your Healy is Positive ground?)Temporarily tape
the ends of the wires that have been removed so that they cannot touch one another, any other wire, or the chassis. Start the car but do not rev it hard. Increase the engine speed to a fast idle of between 750 and 1,000 rpm. The voltmeter should read at least 14V.
Do not ncrease the speed to a point where the voltage generally goes above 20V for longer than 15 seconds or so at a time, otherwise permanent damage can occur to the commutator due to arcing and overheating.
If there is no reading then the brushes may not be contacting the commutator and need replacing or you may have a broken brush spring.
If the reading only gets to about 1 Volt then the field is not getting current. Check that thetemporary link wire is properly connected to the field terminal, the smaller of the two. Try again. If an ohm meter is part of the meter and it has a low resistance range, check the resistance of the field winding, from the small terminal to ground, it should be about 5 to 7 ohms.
A low voltage reading of about 5 to 8 volts indicates that the armature may have a faulty winding.
Before checking the Regulator box, use your meter to verify that there is good continuity between the small wire you have removed form the Generator and the F terminal on the Regulator and the thicker wire and the D terminal also on the Regulator box.
I hope this is all clear, but if not please let me know and I'll try to get it sorted out for you.
Brian
