Power-On Time - Gerima SMA 50?E1 Operating Manual

To avoid damaging the machine, it is essential
to be monitor how long the machine has been
operating continuously ('power‐on time').
All electric brushed motors generate large
amounts of heat in the rotor and stator. Al‐
though the machine is fitted with a fan cooler
that dissipates the heat produced, if the ma‐
chine is subjected to extreme loads (e.g. milling
large bevels, very hard or tough materials) and/
or is run continuously for a long period of time,
the cooling system may not be able to cope with
the amount of heat generated. If the operator
continues to use the machine, the rotor
(armature) may overheat to such an extent that
the winding insulation melts causing a short cir‐
cuit.
Material strength
Aluminium, copper, brass or plastics
Steel up to 400 N/mm²
Steel up to 600 N/mm²
Steel up to 900 N/mm²
Stainless steel
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Do not overload the machine!
The machine can become overloaded if, for ex‐
ample, it continues to be used even though the
bevel being cut is too large for the material be‐
ing milled, or if the cutting inserts have become
blunt and therefore unable to penetrate the ma‐
terial.
Such conditions can lead to large machine vibra‐
tions or even machine breakdown if the arma‐
ture in the motor is bent to such an extent that
Power‐on time
The power‐on time is always expressed as a per‐
centage of one hour.
Example:
If the power‐on time is specified as 50
can use the machine to mill bevels for a maximum
of 30 minutes in an hour and must then leave the
machine to cool for 30 minutes. If the machine is
subjected to heavy loads, the power‐on time
might be 20 %, which means it can be used for
12 minutes in any hour and must be left to cool
for 48 minutes. Before completely switching off
the machine, we recommend running the machine
for one or two minutes in idle mode (unloaded) so
that fan can continue to draw cool air through the
machine.
Power‐on time
bevel width
< 10mm > 10mm
80% 60%
60% 35%
50% 25%
40% 20%
40% 20%
the rotor and stator rub against each other,
overloading the windings and blowing the motor.
To prevent this sort of damage when milling large
bevels and/or hard materials, never try to ma‐
chine the bevel in a single pass, always use multi‐
ple passes, and do not forget to change the cut‐
ting inserts before they become blunt or worn.
.
11
V.02 .22.03.10.ENG
%, then you
Speed adjustment
Speed setting
6
6
5
4
2‐4