4 Explosion protection for MSK motors
4.1 Features
Rexroth MSK motors in ATEX design are suitable for the use in explosive at‐
mospheres of the zones 2 and 22. The motors comply with device group II,
category 3 according to European Directive ATEX 94/9/EC. The labeling of
motors is made with an "S" on the 25th place of the type code.
Fig. 4-1: Type codes for ATEX labeling
Category Usable in
zone
Also
usable in
zone
Basic requirements
1 0 1
2
Equipment designed to be operated in conformity with the operational parameters
established by the manufacturer and ensuring a very high level of protection.
Equipment of this category is intended for use in areas in which explosive
atmospheres caused by mixtures of air and gases, vapors or mists or by air/dust
mixtures are present continuously, for long periods or frequently. Equipment of this
category must ensure the required level of protection, even if there are only rare
incidents, and is characterized by means of protection, meaning that
● in the event of failure of one means of protection, at least an independent
second means of protection provides the required level of protection; or
● in the event of two faults occurring independently of each other, the required
protection is guaranteed.
20 21
22
2 1 2 Devices which are designed such that they can be operated in conformity with the
parameters specified by the manufacturer while ensuring a high degree of safety.
Devices of this category are intended for use in areas where it must be expected that
an explosive atmosphere comprising dust-air mixtures occurs occasionally. The
equipment-based explosion protection measures of this category ensure the required
degree of safety, even in case of frequent device malfunctions or error conditions
which must be usually expected.
21 22
3 2 - Devices which are designed such that they can be operated in conformity with the
parameters specified by the manufacturer while ensuríng a normal degree of safety.
Devices of this category are intended for use in areas where it is unlikely that dust
whirling up generates an explosive atmosphere and, if such an atmosphere is indeed
generated, that it occurs only rarely and for a short period. Devices of this category
ensure the required degree of safety during normal operation.
22 -
Tab. 4-1: Explosion hazard category and zones according to ATEX (meaning)
The motors are prepared with an inlet and outlet for flushing. The flush does
not influence the classification for Ex-protection valid for these motors and is
not necessary for them. The motor can be flushed via the screwed connec‐
tions. For the flushing, only a passive gas may be used (e.g. air or inert gas
without any explosive particles). The flushing gas must be free of particles,
such as water, oil, dust, chemicals or other conductive or aggressive sub‐
stances in order to guarantee the type of protection. For motor purging, addi‐
tional components are necessary. The qualification, examination and certifi‐
cation must be carried out by the system planner, the installation builder or
the machine builder. The latter shall examine the suitability of components for
DOK-MOTOR*-MSK*EXGIIK3-PR09-EN-P Bosch Rexroth AG 23/175
Synchronous Servomotors MSK For Potentially Explosive Areas
Explosion protection for MSK motors
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