One last question - OC-46 charging system

[Ed Miller]

I've got the 12 Volt system on the diesel.   I checked the two terminals on the generator and don't seem to have any voltage there.   Is this a standard generator that I can get new brushes for from NAPA?   Any other things to look for?   I'm assuming the voltage regulator is also  bad, it looks original. I"ll check it but does anyone know a good replacement for this?  

Thanks in advance.

Ed

[TDLMOMOWERS]

See if there are any numbers on the generator, and what kind it is. Napa should be able to locate the proper brush set from the generator numbers. Make sure that you polarize the system any time you unhook anything in the charging system. Napa can cross reference a lot of OEM numbers to the NAPA number. Do you have a wiring diagram for the charging system? Check continuity on all the wiring to the regulator and generator and the AMP guage and the on-off switch.

[440roadrunner]

First I apologise for not knowing what  "circuit"   the field uses on these,  but there are a few things you can check.    

FIRST  thing to find out,  is the type of generator and type of field circuit.  I don't know if all Olivers/ Cletracs  use the same system or not

One type of field is grounded internally,  and the "other end"  (think of it as simply an electromagnet)  is brought out to the F terminal (small terminal) of the generator.  This type of circuit  needs  current fed into it in order to charge.   In other words,  you jumper the F to the G (A)  or armature terminal to make it charge.   These are known as "internally grounded"  or "B circuit"

The second type of field circuit has one end connected to the (A)rmature.   This means of course that to make this circuit charge,  instead of feeding current TO the F terminal,  you ground it to get the thing to charge.  These are  "externally grounded"  or "A"  circuit

One reason  I hesitate to say  that "All Delco are  "X"  type" and "all Autolite are Y"  is because they are not  "all."    Most common  Delco passenger cars and Autolite are "A"  circuits,  but both  manufacturers  made both types!!!!    I BELIEVE   that Ford  made a change in circuit type in it's tractors,  and since I'm not a Ford collector,  I can't elaborate on that

 
Now,  there is a last  "gotcha"    All generators have a "cutout"   either just a cutout only  (types with no regulator)  or in the case of a regulator,  which has either two or three relays,   the cutout is one of the other relays.   The contacts of this relay  ARE IN SERIES  with the A/G termainal and the battery.   What this means is,  if the cutout is burned up, or the contacts burned,   it will not conduct current to the battery.

Second,  a "three relay"  type regulator  also has, in addition to the 1--voltage regulator relay,  2--cutout relay,  it also has  3--the current limiter relay.   This relay  drops charging current down  if the charging current becomes to great---in order to protect the generator.   This too,  has contacts that can be damaged    

So if you "jumper"  the field circuit  and it won't charge,   the next thing to try is jumper from the A/G terminal on the regulator to the B (battery)  terminal.  

BE ABSOLUTELY SURE  that you determine the type of circuit you have, l because the two types are polarized  (flashed)  differently.     You are not, by the way, polarizing the regulator as many think.   You are polarising the generator.   What you are doing,  there,  is setting up a weak magnetic field in the iron core  of the generator,  so it can "self generate"  from a cold start  AND WILL  generate in the correct polarity.  

If others can't help here in this determination,  post back.  There are some simple continuity checks you can make to determine if it's  "A"  or "B"  circuit,  and which polarization/  test procedure to go by.   One last time,  it depends on whether the field circuit is internally grounded,  or internally connected to the armature.   One way to do this,  if the brushes are easily accessable,  (removable brush shield)   is to slip some thin cardboard between the brushes and the armature,  to insulate them.   With the wiring disconnected from the generator,  test for continuity  from the F terminal to ground.    If you have continuity,  you have an "internally grounded" Field,  and if none,  you have an "externally grounded"  Field circuit,  the type that you must ground  F to cause a charge.

To polarize  externally grounded  Field type generators, (A circuit)  wire everything up and simple  "flash" between  "B"  (battery)  and A/G  (armature) terminal on the regulator

To  polarize internally  grounded types, (B circuit)  disconnect the F wire at the regulator,  and momentarily  "flash"  it to the B (battery) terminal


A few more rants and raves.   You may know,  that generally,   6V cars, trucks and tractors  could be EITHER pos or neg, ground,  and even a few 12V  generator equipped truckes were pos  ground.   WHY DOES IT MATTER?   You can polarize the generator either way,   the starter does not care,  and neither does the (maybe electric) wiper motor nor the heater motor.   The radio  "may"  care depending on it's circuit.   Some gauges systems "don't care"   except for the ammeter which can be reversed.  So can the coil polarity.

THE ONE THING  that matters for generator polarity  is the REGULATOR.   Many OEM  regulators  had  contact points construction  such that if you reversed system polarity,  the contact life of the regulator would be severely reduced.     However,  some OEM  and many  aftermarket  regulators were made with improved contact points so that they could be used on EITHER  pos or neg. ground systems.  This of course reduces  stock in the warehouse.  If you look around enough in  "old junk" sometimes you can still find regulators so marked as to polarity.

[boltzie42]

I see this is a 2010 post so hopefully someone can help.  I have an 1957 OC-4 and replaced all the wires.  The Ammeter was not showing a charge or discharge before the rewire and still isn't showing anything.  The previous owner had the battery terminals hooked up backwards, as in not have it correctly set up as a positive ground system.  I just read in the manual that before starting the engine, I have to polarize the generator by "momentarily connecting a jumper lead between the "GEN" and "BAT" terminals on the voltage regulator.  This operation allows a flash of current to flow through the generator field winding which will correctly polarize the generator with respect to the battery.  This procedure must be followed before the engine is started.  Failure to perform the above operation may cause damage to the generator or voltage regulator."  

Can someone please tell me which terminal is the "GEN" terminal and the "BAT" terminal?  My manual states to jump the "BAT" to the "GEN".  The above states "To polarize  externally grounded  Field type generators, (A circuit)  wire everything up and simple  "flash" between  "B"  (battery)  and A/G  (armature) terminal on the regulator"  So....this leads me to believe the "A" terminal is the "GEN" terminal referenced in my manual.  Is this correct?

And....the manual says to "momentarily connect a jumper between the "GEN" and "BAT" terminals before starting" to polarize the generator.  When the jumper is connected between the two terminals, am I supposed to turn the key and not start the engine, then remove the jumper?  Will this effectively flash current?  Or.....does the jumper need to stay in place while I start the engine?  The manual is not very clear on this.

Thanks.