Instructions for use and maintenance
Electric motors <50 V CA
The basic principle of such protection shall be that, in the event of failure, it shall not occur
between a part accessible to the ground or between two parts which are simultaneously
accessible, a tension sufficient to cause a risk of harmful physiological effects in a person who
comes into contact. They are distinguished:
-
Protection connection made according to the system with protection conductor
connected to the ground in an autonomous way compared to the power supply; the
protection can be performed by means of a switch of maximum current or differential
switch;
-
protection connection made according to the system with neutral conductor connected
to the ground at the origin and used as protection conductor (in this case it is not
possible to use the differential protection and therefore the switches of maximum
current must intervene).
Consult the specific regulations.
The coordination and selectivity of all the protections must be guaranteed, in order to
adequately protect lines and equipment; the automatic restoration of the protections after
they have intervened is always prohibited, in so far as this may result in an unsafe condition;
in addition, the intervention of trained personnel for the manual restoration of the system, of
which the electric motor is a major part or part, is mandatory. When present
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