OPERATORS MANUAL JOHN DEERE 4620 TRACTOR

56
Service - Electrical System
Removing and Installing Batteries
Disconnect the battery ground cable from the left-
hand battery first. If removing the right-hand battery,
then disconnect the connector cable from the nega-
tive post of the right-hand battery. Disconnect the
positive battery cable last. Remove the battery hold
down clamp and lift the battery off the tractor.
When installing the battery, overtightening of the
damp may damage the battery.
Connecting Batteries
P O S I T IV E
CABLE
TO
STARTER
CONNECTOR
CABLE
STANDARD TRACTOR
L E F T-H A N D
R IG H T-H A N D
B ATTERY
BA T T ERY
ROW-CROP TRACTOR
Battery Connections
Before connecting the battery, make sure all elec-
tric switches and accessories are turned off. Connect
the positive battery cable first. If installing right-hand
battery, connect the connector cable to the negative
post before connecting the ground cable. Before
connecting the battery ground cable to the left-hand
battery, momentarily touch it against the negative
post. With all switches and accessories off no sparks
should occur. Connect the ground cable.
Tighten the clamps securely. Coat the terminals
and connectors with vaseline mixed with baking soda
to retard corrosion.
Storing Batteries
If the tractor is to be stored for more than 30 days,
remove the batteries. With the electrolyte level at the
bottom of the split ring, charge the battery before
storing it. After every 30 days the battery is in stor-
age, bring it back up to full charge. To minimize self
discharge, store the battery in as cool a place as pos-
sible so long as the electrolyte does not freeze. Elec-
trolyte at 1.220 specific gravity (corrected reading)
will freeze at -31 degrees F. At 1.260, the electrolyte
will freeze at -75 degrees F.
Alternator and Regulator
The alternator located at the right-hand front side of
the engine provides electric current for charging the
batteries and for other electrical requirements of the
tractor. A transistorized alternator-regulator is
mounted at the rear of the alternator. The regulator
controls the voltage output of the alternator.
Preventing Damage to Alternator and Regulator
Failure to observe the following rules will probably
result in damage to the tractor wiring, the alternator,
or the regulator.
(1) Never attempt to polarize an alternator.
(2) Disconnect the batteries when working near or
when working on the alternator.
(3) If the alternator wiring is disconnected, be
sure that it is properly connected BEFORE the batter-
ies are connected.
(4) The alternator must not be operated on an
open circuit (batteries-disconnected or with a discon-
nected wire from the alternator to the battery). The
high voltage from open circuit operation may damage
the alternator. -
(5) Do not short across or ground alternator or
charging circuit terminals. The alternator output ter-
minal is “ hot” at all times.
(6) When connecting a battery charger or a boost-
er battery, connect POSITIVE (-F) to POSITIVE ( + )
and negative to a good ground on the tractor frame.
Adjusting Belt Tension
After every 200 hours of operation or whenever
necessary, check the belt tension.
With the mounting bolt and adjusting cap screw
loose, apply outward force to the FRONT alternator
frame until a firm push (25-pound force without air
conditioning, 20-pound force with air conditioning) on
a belt midway between the two pulleys will deflect
that belt one inch. Tighten the alternator in this posi-
tion. Alternator may be permanently damaged if pres-
sure is applied to the rear alternator frame.