Testing Generators on the Vehicle or Tractor, Part 1

Testing 'A' circuit generators are pretty easy.  First, disconnect the 'F' terminal either at the generator or the regulator.  You must do this to prevent damaging the regulator if it is still good.  Start the engine and have someone watch the ammeter (which is the gauge that should be being used with a generator) and then use a jumper wire and ground the 'F' terminal on the generator.  If the generator is good, it will go into full charge instantly and show that way on the meter.  What ever you do, don't touch the 'F' terminal on the regulator when you do this.

If the generator does go into full charge then it is probably good.  So after you reconnect the 'F' wire, if it doesn't charge then the problem is probably the regulator and will need replaced.  You could also remove the regulator's cap and try to clean the contacts to see if it will work.  Also make sure the regulator has a good ground as that will also cause it to not work.

One last thing you can try, is to re-polarize the regulator.  This has never worked for me, as my problems have always been elsewhere, but it's worth a try.  To polarize the regulator on an 'A' circuit system, With the engine off and everything connected including the battery, (positive or negative ground) take a jumper wire and momentarily touch the regulators 'BAT' terminal to the 'ARM' (or 'GEN' terminal, which ever way it is marked).  Only hold the wire on it for a second and them remove it.  It will spark when removing it and that is normal.  If there is no spark, check the wiring to make sure you have battery juice to the 'BAT' terminal by checking it with a test light or meter.  Once again, DO NOT touch the 'F' terminal or it will instantly fry the regulator.  (My directions for polarization are only general and you should follow the directions you receive with the new regulator if they differ from what I have stated here!)

On some regulators the 'ARM' terminal is in back or underneath and may be hard to access.  In that case you can jump from the 'BAT' to the 'A' terminal on the generator as the wire from the 'ARM' terminal goes directly to the 'A' terminal. 

One final thought today, most regulators used with 'A' circuit Delco generators have either three or four terminals.  The three terminal units terminals will be marked 'BAT', 'ARM' (or 'GEN') and 'F'.  Four terminal units are marked 'L', 'BAT', 'F' and the terminal in back or on bottom 'ARM'.  The 'L' terminal on the four terminal unit, if used, is for the vehicle's or tractor's lights and is usually wired directly to the light switch.

I will cover 'B' circuit generators in the next post.

Generators, 'A' or 'B' Circuit?

I thought I'd throw in a little information about auto and tractor generators this week.  Please consider this information as general in nature.  You should find an experienced electrical technician for proper identification and testing.

The main difference in the various generators that were produced in older vehicles and tractors is that there were either 'A' circuit or 'B' circuit units.  What this means is how the units output, is controlled by the regulator, regulating the field current (to the 'F' terminal on the generator).  In the 'A' circuit generators, which were mainly Delco units, were controlled by the regulator varying the ground to the field.  In 'B' circuit generators, the regulator applied current to the field, which was internally grounded.

Most 'A' circuit units were on GM products and many farm and industrial tractors.  'B' circuit units were mainly found on Ford products and possibly industrial units, but there were a few 'A' circuit Ford tractor units produced.   Later generators on Ford tractors were all Lucas brand 'B' circuit generators.  Other manufacturers like Autolite and Prestolite made generators also, and they could be either 'A' or 'B' circuit.  Delco may have made a 'B' circuit generator, but I've never came across one!

I will offer a little testing and advice for generators in the next post!

Fewer Breakdowns

I've been traveling the last week and a half and noticed that there are fewer cars broke down on the road than we used to see, say 30 years ago.  Technology has made them last longer and made than more reliable than earlier vehicles.  Just considering the shear number of vehicles out there, you'd think there should be hundreds of broke down vehicle on the road.  With the advances in tire design, you seldom even see flat tires out there either.  Unfortunately, the trade off being that you can no longer work on your own cars with just basic mechanical skills any more!  Is this a good thing or a bad thing?

Once these cars quit running they must be towed to a mechanic to get them running again.  I remember many times on my old 60's to 70's cars and pickups, being able to repair them on the road or able to limp them home where I could fix them.  Those were the days!

Doctors VS. Mechanics, Who Should Be Paid More?

If you think about this for a minute and compair the two jobs, you may see that the mechanic may actually have a tougher and harder job than most doctors.

First off, the human body is only made in two models, male and female!  Though there are different sizes and ages that play a factor in their treatment, basicly the internal organs are all the same and don't change when a new baby comes along.  Granted there are always new technics and drugs for treatment that come about and new diseases that pop up, not all doctors will learn all of these as only specialists will come along to learn and use some them.

Now look at all the automobiles coming off the rack each and every year.  Consider all the manufacturers and all the models of vehicles they produce.  Then throw in all the different engine sizes and transmission options and even body options and everything is different and nothing is interchangable, none of them have the same readings when testing and diagnosing.  Every year they produce new models with something more complex and difficult to diagnose and work on!  So when you bring your car into the mechanic, he now has to go online and learn how to diagnose and fix your car.  Basic mechanic skills that were learned years ago that would allow a mechanic to fix almost any car, do not come into play now.  Granted they help and without them they would not even know where to start, they really only aid in physically identifing and changing the defective parts.

Every time a patient goes to see the doctor, the doctor relies on his knowledge and experience to treat the patient.  When a person brings in their devective vehicle, the mechanic is faced with a literal nightmare of wires and components that he has to stop and learn how to fix on the spot!

Who do you think should be paid more?