Electrical System Checks
WARNING
Disconnect the battery before opening the com-
partment cover or inspecting or repairing the elec-
trical system. If a tool causes a short circuit, the
high current flow from the battery can cause per-
sonal injury or property damage.
The capacitor in the controller can hold an electri-
cal charge after the battery is disconnected. To
prevent electrical shock, disconnect the battery
and discharge the capacitor before inspecting or
repairing any component in the drive unit com-
partment. Always wear safety glasses.
CAUTION
The correct meter polarity is necessary for the
checks. The voltage checks are made between the
point indicated and battery negative. Connect the
meter negative to battery negative.
Always disconnect the battery and discharge the
capacitor before disconnecting cables from the
controller. Never put power to the controller with
any cables or wires disconnected. Never short
any controller or motor terminal to the battery. Al-
ways follow proper procedure when working in
the electrical system.
1.
Turn the key switch to the OFF position.
2.
Disconnect and separate the battery connec-
tors.
NOTE:
The battery does not have to be removed to
check the specific gravity.
3.
Check the specific gravity of the battery. If the
specific gravity is less than 1.260, the battery is
not fully charged or is damaged. A fully charged
battery has a specific gravity of 1.270 to 1.290.
A discharged battery has a specific gravity of
approximately 1.165 or less. Refer to Indus-
trial Battery 2240SRM0001.
4.
Remove the drive unit compartment covers. See
Periodic Maintenance 8000SRM1635
5.
Discharge the capacitor. See Special Precau-
tions in this section.
6.
The electric lift truck has a two-wire system.
The frame must not be a common electrical
path. Using an ohmmeter, check for 50,000
ohms or more between each terminal of the bat-
tery connector (truck end) and a clean connec-
tion on the frame. Remove any electrical paths
between the controller and the frame of the lift
truck. Carbon dust in a motor or other parts
can cause an electrical path. Check for addi-
tional equipment that may provide an electrical
path to the frame.
7.
Check for voltage between each terminal of the
battery connector (battery end) and a clean con-
nection on the frame. Normally there is small
voltage (less than 30% of the battery voltage)
between the battery and the frame, even
though the resistance is very high. A higher
voltage can indicate a dirty or damaged battery.
Clean battery and battery compartment as nec-
essary.
8.
Visually check for parts or wires that are loose
or damaged.
WARNING
Some checks require the battery to be reconnec-
ted. Do not connect the battery until the point of
the procedure when you are directed to do so.
Raise the drive wheel of the truck and position on
solid hardwood blocks to prevent unexpected
movement when working with the battery connec-
ted.
9.
Always follow proper procedure when working
in the electrical system. See Table 1.
NOTE:
Make an identification of any wires before
you disconnect them. The wires must be connected
correctly after checks or repairs.
2200 SRM 1632
Electrical System Checks
7
