Eibenstock EBM 352/3 Originalbetriebsanleitung Seite 26

At the beginning, it is better to drill very slowy because the bit only
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meshes with a fraction of its cutting area with the material. If you drill
too fast or with a pressure which is too high, the bit can be off centre.
You have hit reinforced iron when you recognise while drilling that the feed
rate gets very low, when you need to use more force, or when the water
leaking from the bore hole clearly shows some metal chips.
Reduce the pressure on the drill bit to cut through the reinforced iron without
any problems You increase the pressure again when you have cut through
the reinforced iron.
Drill bit extension
If you have to drill deeper than the usable length of your drill bit is:
 First, only drill to the point the usable length of the bit reaches.
 Remove the bit and pull the centre core out of the hole without moving
the core drilling unit.
 Push the drill bit back into the bore hole.
Screw an adequate extension between drill bit and motor. If the collet of the
drill bit is 1¼", please do not forget the copper rings which make the removal
of the drill bit easier.
Overload Protection
In order to protect the operator, motor and drill bit, the EBM 352/3 is equipped
with a mechanical, electronic and thermal overload protection.
Mechanical: If the drill bit is suddenly blocked in the hole, a clutch will
slip disengaging the drill spindle from the motor.
Electronic: To warn the user against overstressing the tool by applying
to high feed force, a LED is mounted on the motor cap. It
does not light during no-load run or at normal load. In case
of over- load, the LED lights red. Now the tool must be
discharged. In case of longer non-observation of the red
indication, the electronics will independently cut the unit off.
After discharge and switching the tool off and on again, you
can continue working.
Thermal: In case of permanent overload, a thermocouple protects the
motor against destruction. Here also, the user is warned by
the overload indicator. Shortly before the maximum
temperature is reached, the indicator flashes red.
In that case, the tool switches off and can only be restarted
after a certain cooling-down period (approx. 2 minutes). The
overload indicator flashes until the machine has cooled
sufficiently and can be used again. The cooling-down time
depends on the temperature of the motor winding and
ambient temperature.
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