Alpha Tool.Com.HK Limited Grinder HSG125 User Manual

							11
action may decrease the rotation speed which reduces the effi ciency of the grinder.
3.  Hold the tool with both hands while starting; the torque from the motor will cause the 
tool to jerk.
4.  When the grinding wheel fi rst comes into contact with the work surface or when the 
wheel is new, make contact slowly.
5.  Keep moving the tool in a circular motion to prevent grooving in the work surface.
6.  Hold the unit tightly to prevent it from walking, and remove the high spots in the work 
surface from the top down.
HIGH-SPEED ANGLE GRINDER OPERATION
  CAUTION!
Always be sure that the tool is switched off and unplugged before adjusting or checking 
function on tool.  This tool is in accordance with IEC 60745, and it can be connected to 
electrical outlets without ground protection because of double installation.  Radio suppres-
sion complies with the international standard CISPR 14.
 MAIN CONNECTION
Connect only to single-phase AC current supply and only to the main voltage specifi ed on 
the rating plate. 
 SWITCHING ON AND OFF
  CAUTION!
Before plugging in the tool, always check the working voltage be sure that the voltage 
specifi ed is on the name plate.  Before plugging in the tool, always check to see that the 
slide switch actuates properly and returns to the “OFF” position when the rear of the slide 
switch is depressed.
Switching on:  
Switch can be locked in “ ON” position for operator 
comfort during extended use.  Apply caution when 
the locking tool is in the “ON” position and maintain 
fi rm grasp on tool. 
Push sliding switch to the forward position and 
depress the front part of the switch to lock into 
position as shown in Figure 3.  
Figure-3
ON POSITION 
						

							12
Switching off:  
To unlock, depress the back of the sliding switch.  
The switch will automatically move back as shown 
in Figure 4.
  BEFORE USE
  DANGER!
Before using the machine, check the following items.  In particular, check items 1 to 5 before 
plugging the power supply cord into the power outlet.
1.  Check the working voltage.
–  Be sure the voltage specifi ed on the rating plate is the voltage available at the 
power outlet.  If the machine is used with higher voltage than specifi ed, the motor 
will burnout.  Any attempts to do so may damage the polisher and/or cause an 
accident.
2.  Make sure the ON/OFF switch is off.
–  If you plug in the power supply cord without realizing that the switch is ON, the 
machine will start and may cause an accident. Make sure the on/off switch trigger 
is out and the locking button is not engaged.
3.  Inspect the protective wheel cover.
–  Do not remove the wheel cover.  It will protect you if the grinding wheel breaks. 
–  Be sure to fi rmly attach the grinding wheel or any optional accessory.
4.  Inspect the grinding wheel.
–  Check if  you have a specifi ed wheel.
–  Never use cracked, chipped, or any damaged wheels.
–  Follow the procedures specifi ed in the instruction manual to properly attach ap-
plicable accessories.
5.  Check the power outlet.
–  When the plug of the power supply cord is easily pulled out of the power outlet, 
the outlet should be replaced.  For such task, consult an electrician.  If the power 
outlet is used on a continuous basis, it may overheat and cause accidents. 
6.  Perform test runs.
OFF POSITION
Figure-4 
						

							13
  WARNING!
1.  Before turning the switch ON, make sure the rotating parts are not touching   
anything. If the switch is turned ON while they are in contact with anything    
else, the wheel may get damaged and may cause injuries.
2.  When a new wheel is attached and the switch is turned ON, keep your body    
well away from the exposed sides of the wheel for a moment until the machine    
reaches its full speed.
It is very dangerous to perform grinding operations using cracked, chipped or damaged 
wheels. Before starting grinding operations, keep the wheel away from anyone nearby. Be 
sure to perform a few test runs to check whether there are any abnormalities.
Test run duration:
After replacing a wheel..........……………………at least 3 minutes
Before starting operations each day...................at least 1 minute
  ABOUT DOUBLE INSULATION
This machine is designed with double insulation. Two insulations are used between the 
conductor and the outer body of the machine.  An electric machine with the double insulation 
highly improves safety from electric shocks.  Do not attach or replace unspecifi ed parts and 
do not assemble incorrectly. This may cause the  insulation to malfunction.   
   LAWS AND REGULATIONS OF NOISE LEVELS
Please observe local laws and regulations regarding noise level in order to avoid disturbing 
surrounding areas.  Install a soundproof wall if required to comply with the local laws and 
regulations. •
• 
						

							14
USING THE TOOL 
  PROTECTIVE COVER INSTALLATION
  CAUTION!
The protective cover should be used to prevent the dust and fl ying debris from hitting the 
operator or from going inside the tool.  Failure to do so can shorten the life of the tool and 
void the limited warranty.
1.  Slide the protective cover onto clamping collar so that 
the lip on the protective cover fi ts into the groove on 
the tool.
2.  Position the protective cover with the shield facing 
backwards as shown in Figure 6.  Push down until 
the protective cover is fi rmly seated on the clamping 
collar.
3.  Tighten the clamping screw to a snug 
fi t.  The protective cover should not be 
able to move.
Groove
Figure-5
Figure-6Figure-7
Figure-8 
						

							15
 ASSEMBLING SPINDLE ATTACHMENTS
  CAUTION!
Do not leave threaded accessories on the spindle of the tool for extended periods of time, 
as this may result in making it diffi cult to remove these accessories.
Note:  The Alpha
® High-Speed Angle Grinder has a 5/8”-11 spindle thread .  It comes with 
two Inside Flange and Locking Flange sets: 20mm Arbor for 4” discs and 7/8” Arbor 
for 4-1/2” to 5” discs.  
To attach an approved spindle attachment to the tool, follow the steps below:
  CAUTION!
Always disconnect the plug from the electrical outlet before carrying out any work on the 
machine.
Mount the inside fl ange. (use the 
20mm Inside Flange and Locking 
Flange Set for 4” discs or the 7/8” 
Inside Flange and Locking Flange Set 
for 4-1/2”-5” discs).
Add the working tool and then the locking fl ange as shown in Figure 10 and 11. 1.
2.
Figure-9
Figure-11 Figure-10
Cutting Wheel in photo is not included. 
						

							16
While depressing the spindle button, 
rotate the spindle until the spindle lock 
button is inserted into the gear, thus 
locking the spindle in a fi xed position.
With the spindle locked in place, turn the 
locking fl ange clockwise until hand-tight.
Use the 34mm pin spanner wrench to secure tightly.
 
 DISASSEMBLING SPINDLE ATTACHMENTS
Please follow the reverse procedure for disassembling the working tool from the grinder. 3.
4.
5.
Figure-13
Figure-12
Figure-14 
						

							17
CHECKING AND REPLACING THE CARBON BRUSHES
In order to keep the tool running correctly, you need to check the carbon brushes after 
every one hundred hours of use.  Carbon brushes wear out over time based on the 
grinder’s usage.  If a carbon brush is worn out, it may cause the motor to malfunction or 
fail to run.  The carbon brushes should be replaced before the twisted wire reaches the 
bottom of the slot.
 
  DANGER!
Be sure to unplug the power cord from the outlet before servicing the unit, to prevent 
electrical shock or starting the tool accidentally.
 REAR COVER REMOVAL
1.  Remove the rear case screws.
2.    Hold grinder with one hand and pull the 
rear case straight back with the other 
hand.
NOTE: Do not  twist case in a side-to-side 
motion when pulling back.
2  Pull back the rear case until the carbon 
brush assembly is exposed.
Figure-15
Figure-16
Figure-17 
						

							18
 CARBON BRUSH HOLDER REMOVAL
Disconnect the power wire from carbon brush 
holder.
Note:  Each grinder has 2 carbon brushes located 
on opposite sides of each other.  
2.  Remove the carbon brush holder from the 
motor housing by pulling the holder out with 
a pair of needle nose pliers.
3.  With the carbon brush holder removed, you 
can check and clean the armature commu-
tator.  The commutator is the contact points 
that the carbon brushes ride on when the 
motor is running. (See page 20 for cleaning 
the commutator) 1.
Carbon Brush
Coil 
Spring
Carbon 
Brush Holder Motor
Housing
Figure-18
Carbon Brush Assembly Parts
Figure-19
Figure-20
Power Wire 
						

							19
4.  Pictured on the left below, is a worn carbon brush in the holder (Note: the twisted 
wire is at the end of the slot and the carbon brush is almost fl ush with holder).  On 
the right below, is a new carbon brush in the holder.
NOTE: Carbon brushes sometime wear at different rates; however, both carbon brushes 
should be replaced at the same time.  
  
  WARNING!
Replacing the carbon brushes in this unit with non-Alpha® parts could damage the unit, and 
will void the warranty. 
 CARBON BRUSH REMOVAL
1.  The carbon brush can be removed from the holder by pulling back the carbon brush 
spring and moving it to the side as shown in the photo on the left below.  After reas-
sembly, press the carbon brush in and out of the holder to make sure it moves freely and 
the twisted wire is not hitting the wire terminal or spring (see photo below on right).
 
Carbon Brush
Spring
Twisted Wire
Removing and Installing the Carbon Brush
Worn and New Carbon Brushes
WornNew
Figure-21
Figure-22 
						

							20 2.  Remove the old carbon brush and disconnect the wire terminal. If the inside of the 
holder is fi lled with dust, clean it before installing the new carbon brush.  Upon instal-
lation of the new carbon brush, make sure the twisted wire is in the slot and behind 
wire terminals on the holder (as in Figure 22 right photo).
3.  With the carbon brush holder removed, you can check and clean the armature com-
mutator.  The commutator is the contact points that the carbon brushes ride on when 
the motor is running.
 CLEANING THE COMMUTATOR
1.  The commutator should be clean and shiny. If it is dull 
and black, you can clean it with a commutator cleaning 
stone.
2.  To clean the commutator, press the commutator 
cleaning stone against the commutator and 
rotate the armature by turning the spindle 
shaft by hand.  Continue for a minute or until 
commutator is clean and shiny.
 INSTALLING THE CARBON BRUSHES 
2.  Reinstall the carbon brush holder into the slot on motor housing. Reconnect 
the power wire, ensuring that the wire path is correct.   
3.  After both carbon brushes have been replaced, you can reassemble the rear cover.  
Make sure the power wires are in the tool to prevent pinching of the wires.
Figure-23Figure-24
CleanDirty
Clean and Dirty Commutator
Figure-25