Maintenance And Inspection - Hitachi GP3V Instrucciones De Manejo

English
Adjusting the number of revolution
These models are equipped with an electronic infi nite-
variable-speed drive and can change the number of
revolution according to a use.
If you turn and set the dial scale (Fig. 6) to 6, the number
of revolution increases, and if you turn and set it to 1, the
number of revolution decreases.
Before use, set the number of revolution using the dial.
In so doing, refer to the following table as a rough guide.
Dial Use
1 Polishing, fi nishing
Removal of paint
2
or coat
3 Removal of rust
4 Removal of burrs
5 Grinding
6 Rough grinding
NOTE
Use caution not to turn the dial scale to any value below
1 or above 6.
WHEEL SELECTING METHOD
Types of wheels are varied according to the materials to be ground. Select a wheel appropriate for the material to be ground.
The following table is an outline of wheels and materials to be ground.
Materials to be ground
Mild steel, hard steel,
forged steel
Cast iron
Brass, bronze, aluminium
Ceramic
Synthetic resin
Small-scaled wheels with shaft are prepared for grinding small surfaces. Their dimensions and shapes are shown in
"Selecting accessories".
Since wheel shaft diameter is 3 mm, use the collet chuck for 3 mm shaft sold separately by your HITACHI dealer as an
optional accessory.

MAINTENANCE AND INSPECTION

1. Inspecting the wheel
Ensure that the wheel is free of cracks and surface
defects.
2. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure that
they are properly tightened. Should any of the screws be
loose, retighten them immediately. Failure to do so could
result in serious hazard.
3. Maintenance of the motor
The motor unit winding is the very "heart" of the power
tool. Exercise due care to ensure the winding does not
become damaged and/or wet with oil or water.
4. Inspecting the carbon brushes (Fig. 7)
The motor employs carbon brushes which are
consumable parts. Since an excessively worn carbon
brush can result in motor trouble, replace the carbon
brushes with new ones having the same carbon brush
No. ⓐ shown in the fi gure when it becomes worn to or
near the "wear limit" ⓑ. In addition, always keep carbon
brushes clean and ensue that they slide freely within the
brush holders.
Rotation speed (min )
-1
GP3V GP5V
7000 2000
11400 3250
15800 4500
20200 5800
24600 7050
29000 8300
Grain Grading
WA 60 − 80
C 36
C 36
WA 60 – 80
C 36
Caution when using near welding equipment
When using the grinder in the immediate vicinity of
welding equipment, the rotational speed may become
unstable. Do not use the grinder near welding equipment.
Precautions on operation
(1) Lightly press the wheel to the material to be ground.
When grinding
is necessary. Use a hand grinder with high-speed
revolution, minimizing the pressing force.
CAUTION
When using the tool at any value except the full speed
(Dial scale 6), the motor cannot be suffi ciently cooled
due to the decreased number of revolution. This could
result in the risk of burning and damaging the motor
before an overload protective mechanism starts to
function.
Make sure that you use the tool by lightly applying it
to the surface of material when you use it at any value
except the full speed (Dial scale 6).
(2) Dressing the wheel
After attaching a wheel, correct defl ection of the wheel
center by using a dresser. If the wheel center is eccentric,
not only precise fi nishing cannot be achieved but also
grinder vibration increases, lowering grinder accuracy
and durability.
A clogged or worn wheel will spoil the fi nishing surface or
lower grinding effi ciency. Occasionally dress the wheel
by applying the dresser.
Bonding degree
P
M − O
J − K
M
K − M
5. Replacing carbon brushes (Fig. 7)
〈Disassembly〉
(1) Loosen the D4 tapping screw ⓒ retaining the tail cover
ⓓ and remove the tail cover.
(2) Use the auxiliary hexagonal wrench or small screwdriver
to pull up the edge of the spring ⓔ that is holding down
the carbon brush. Remove the edge of the spring toward
the outside of the brush holder ⓕ.
(3) Remove the end of the pig-tail ⓖ on the carbon brush
ⓗ from the terminal section of brush holder and then
remove the carbon brush from the brush holder.
〈Assembly〉
(1) Insert the end of the pig-tail of the carbon brush in the
terminal section of brush holder.
(2) Insert the carbon brush in the brush holder.
(3) Use the auxiliary hexagonal wrench or small screwdriver
to return the edge of the spring to the head of the carbon
brush.
NOTE
Make sure the end of the spring is not holding the pig-tail.
(4) Mount the tail cover and tighten the D4 tapping screw.
6
materials, high-speed
Structure Bonding agent
m
m
m
m
m
revolution
V
V
V
V
V