Installing Radio Condensers; Generator Polarity Reversal - Cadillac 1937 LaSalle VVI Information

151
E L E C T R I C A L
If the generator charges satisfactorily with the
" F " terminal grounded, the trouble is probably
in the regulator, particularly the cut-out relay,
and the regulator should be replaced or adjusted.
See N o t e 6.
5. If the generator does not charge w i t h the
" F " terminal grounded, remove the lead from
the G E N terminal and strike it against a ground,
such as the motor block, while the " F " terminal
is still grounded. If no spark occurs, the trouble
will be i n the generator. If a spark does occur,
the regulator is at fault.
If the generator charging rate is too high or
too low, investigate the following:
1. A high charging rate m a y be caused by a
shorted battery.
2. A low charging rate m a y be caused by a loose
connection in the charging circuit, sulphated
battery plates or other high resistances.
3. Oxidized points i n any of the regulator
units will cause a high resistance which m a y
result in a low charging rate and a discharged
battery.
Oxidized points m a y be caused b y an incor-
rectly installed radio condenser (Note 4), running
the engine w i t h the generator polarity reversed
(Note 5) or excessive sparking at the points.
Excessive sparking at the contacts and erratic
operation m a y be due to low tension on the upper
contact spring or a misalignment of contact points.
Excessive sparking m a y in time oxidize t h e . c o n -
tacts sufficiently to cause high resistance and
prevent the generator from charging.
The effect of oxidization on the contact points
may be determined without breaking the regulator
seal. T o do this:
1. Disconnect the lead from the " I G N "
terminal on the regulator and connect the ammeter
test leads as shown i n P l a t e 63, F i g . 10 and P l a t e
64, F i g . 14.
2. R u n the engine at a low speed u n t i l 4 or
5 amperes output is being obtained.
3. G r o u n d the " F " terminal of the regulator
and note the difference i n the ammeter reading.
If the reading is 2 or more amperes higher w i t h
the " F " terminal grounded, it indicates an
excessive amount of oxide on the contact points
of the current or voltage regulator units or both.
Note: The generator speed must be held con-
stant and the reading taken as soon as the
ammeter needle maintains a steady
position.
Oxidized contacts should be cleaned with a
t h i n fine-cut contact file. T h e file should not be
allowed to become greasy and should not be used
to file other metals. T h e contact points can be
cleaned without disturbing the regulator setting
if care is taken to avoid bending the contact
springs excessively.
Note: Use the file sparingly on the small con-
tact as the actual contact material is only
a few thousandths of an inch thick.
Never use sandpaper or emery cloth for
cleaning contacts.
4. A n incorrect charging rate not caused by
any of these conditions can be corrected by
resetting the current and voltage regulators.
4. I n s t a l l i n g R a d i o C o n d e n s e r s
W h e n installing a radio suppression condenser
on the generator be sure that it is connected to
the generator armature terminal. O n series
37-50, 60, 65, 70 and 75 cars this terminal is the
left terminal on top of the generator. O n series
37-85 and 90 cars this terminal is on rhe c o m m u -
tator end frame. T h e generator field terminal is
located on the top of the generator on a l l 37
series cars and has a warning tag to caution
against connecting the condenser to it, as this
would result in rapid oxidization of the regulator
contact points.
5. G e n e r a t o r P o l a r i t y R e v e r s a l
A "Reversed P o l e " generator is one i n which
the magnetic poles of the field windings have
become reversed. W h e n this occurs,- it causes
excessive arcing across the contact points of the
cut-out relay, w i t h the result that the points will
eventually become fused together.
T h i s condition can be detected by observing
the action of the car ammeter. If the generator
poles have been reversed, the ammeter pointer
indicates a heavy discharge and the pointer will
fluctuate violently w i t h the engine running, or
may indicate a steady discharge with the ignition
shut off. A rapid and complete discharge of the
car battery will follow.
If the lower end of the current regulator ground
wire—which is carried in the wiring harness that
extends from the regulator box on the dash clown
to the starting motor—is permitted to t o u c h the
battery terminal at the starter, or if any live wire
of the electrical circuit is grounded even momen-
t a r i l y while the regulator ground wire is discon-
nected, the generator polarity will become reversed.
T h i s condition can be avoided by remembering
to d i s c o n n e c t t h e
4
b a t t e r y every time that
electrical connections are to be disturbed. T h e
battery is the first point to be disconnected and
the last to be reconnected..
In cases where the generator has become
reversed i n polarity, as indicated above b y the
ammeter, two correctives are required: T h e
generator polarity must be : reversed back to
normal, as explained below, and the current regu-
lator must be serviced or replaced. T h i s requires
inspection of the cut-out relay contact points.
If they are only slightly burned, they can be
cleaned up w i t h a fine cut contact file. If they
are badly burned or fused, the entire regulator
u n i t must be replaced.
After servicing the regulator, the correct polarity
of the generator magnetic field can be assured by
shorting from the battery terminal across to the
generator terminal on the current regulator box
while the battery is connected. The two ter-