8
INTRODUCTION
This user manual must be read and
understood completely, prior to car-
rying out any operation on the safe-
ty module, by personnel dealing
with all the activities of the module.
It must be stored in a dry clean
place close to where the module is
used for easy consultation.
All the operations described in this
manual must be carried out by
carefully following all the indica-
tions given exclusively by spe-
cialised personnel.
Whenever the safety module is
improperly used, Carlo Gavazzi is
not responsible for the functioning
of the module and its capacity to
guarantee the operator’s safety.
The module does not require inter-
nal maintenance: if it is tampered
or if the case is opened, the mod-
ule looses its safety functions and
the guarantee is annulled.
USE DESTINATION - APPLICATION
The MF1C safety module is used
to detect the shaft stopped condi-
tion in a three-phase or a single-
phase electric motor.
The safety module monitors the
residual voltage on the windings of
the motor and closes its safety
outputs when it drops below a cer-
tain reference level, corresponding
to a residual rotation of the shaft
that is not dangerous for the oper-
ator. The safety output can be
used to prevent the opening of the
guards that block access to the
shaft when it is rotating. When the
power supply of the motor is
switched off, the rotor starts slow-
ing down, thus generating a resid-
ual voltage on the stator windings,
that decreases as the motor is
slowing down, tending to zero.
Also the signal frequency on the
motor windings drops from the
maximum value, in the motor pow-
ered condition, to zero, when the
motor is perfectly stopped. The
module, through a pre-adjust-
ment, obtainable with two trim-
mers (VS1,VS2), allows to set the
threshold value below which the
motor is considered stopped: the
safety relay outputs, that during
normal running and during the first
slowing down phase of the motor
are open, close when the residual
voltage decreases below the set
threshold. When the motor is
restarted, as soon as the voltage
exceeds a second threshold (pre-
set and equal to double the previ-
ous one), the outputs reopen.
INSTALLATION
The module must be installed
according to the applicable stan-
dards in force in the country of use
when the machine is not powered
and with no dangers for the oper-
ator. The module must be fixed on
DIN rail and installed in an electri-
cal board with a minimum protec-
tion degree equal to IP54, in
absence of ionizing and non-ioniz-
ing radiation (laser, X-ray, ultravio-
let ray, microwave, etc.).
Summary of Contents for MF1C
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