Supplementary installation, operating and maintenance instructions English
Explosion-proof three-phase asynchronous motors with squirrel-cage rotor for high voltage
815001 Edition 09.2020
12
characteristic curve (initial temperature 20°C) for the ratio I
A
/I
N
- is not longer than the specified t
E
time.
Electrical machines with ignition protection type increased safety “eb” for heavy starting (starting time > 1.7 x
t
E
time) must be protected by a start-up monitoring system in accordance with the information on the Decla-
ration of Conformity and must be explicitly certified for this application.
Thermal machine protection by direct temperature monitoring of the winding is permissible
if
this is certified and the t
A
time is indicated on the rating plate. The
Ex-protection is guaranteed
by temperature sensors according to DIN VDE V 0898-1-401 in combination with trigger devices with
protection type identification II (2) G. For pole-changing motors, separate protective devices locked
out from each other are required for each
speed level.
2.3 Risk
assessment for electrical machines of ignition protection type increased safety “eb”
Ignition risk on stator windings
The stator windings are designed and manufactured using an insulation system tested according to IEC/EN
60079
–7:2015 section 6.2.3.1. No further measures are therefore necessary if the sum of the factors is less
than or equal to 6 for the risk assessment with regard to possible discharges at stator windings in accord-
ance with EN 60079-7, Annex G.
If the sum of the factors is greater than 6, the machine must be pre-purged before starting. The ma-
chine is prepared accordingly.
See annex “Pre-purge before start-up”
Ignition risk in the air gap with squirrel cage rotors
A risk assessment has been carried out by the manufacturer regarding possible sparking in the air
gap of squirrel cage rotors. If the sum of the factors is greater than 6 for the risk assessment for
squirrel-cage rotors according to IEC/EN 60079
–7:2015, the machine must be pre-purged before
starting. The electrical machine is prepared accordingly and is provided with an additional label.
Additional sign: Pre-purge required before start-up
.
See annex "Pre-purge before start-up"
In order to draw the attention of the operator to the special measures required to avoid sparking based on
the risk assessment, the machine marking has an “X” at the end (as per IEC/EN 60079–0, section 29.3.e)
3.
Information about ignition protection type increased safety “ec”
3.1 Protective principle/labelling
Ignition protection type for electrical equipment in which the equipment is not capable of igniting a sur-
rounding explosive atmosphere in normal operation. The design ensures that the risk of arcs or sparks
that could cause an ignition hazard during normal use is minimised.
Prevention of sparks and other ignition sources
Enclosure at least IP54
Observance of creepage and clearance distances
Special attention to insulation materials and seals
Temperatures of the outer and inner surfaces must be lower than the ignition temperature during normal op-
eration
Tests:
Insulation test
Temperature measurement
Additional tests for certain equipment (FI operation)
Areas of application:
Equipment zone 2, category 3G (Gc)
Marking of the motors with EC Type Examination Certificate according to Directive 2014/34/EU:
II 3 G Ex ec IIC T1/T2 or T3 Gc
The instructions given under 2.2 and 2.3 also apply in full to the ignition protection type increased safety “ec”.
3.2 Risk assessment with regard to possible spark formation with electrical machines in ignition pro-
tection type increased safety “ec”
