NORD Drivesystems B1091 - Manual (Page 19)

www.nord.com B1091-GB-4613 -19-
8. Options for motors for
use in Zone 22
8.1 Inverter operation option
ATEX NORD motors for Zone 22 are suitable for inverter operation due to the design of their insulation
system. Because of the variable speed range, temperature monitoring with PTC resistors or temperature
monitors is necessary. For safe planning and use, the engineering guideline for the operating and assembly
instruction B1091-1 must be observed. The engineering guideline provides information about the necessary
requirements for inverter operation and about the permitted speed ranges.
8.2 External fan option
Motors with the additional labelling F (e.g. 80S/4 3D F) are equipped with an external fan and must be
monitored via the integrated temperature sensor.
Notice!
The motor may only be operated together with the external fan! A failure of the external fan can lead
to the motor overheating and therefore endanger property and/or persons. Observe the operating
instructions for the external fan!
The power supply for the external fan is provided independently via the external fan terminal box. The
external fan power supply must be identical to the voltage rating given on the type plate. The external fan
must be protected against overheating with suitable monitoring equipment! The IP protection classes of the
external fan and motor may be different. The lower IP protection class applies to the drive unit. The cable
glands must at least correspond to the protection type specified on the type plate. Unused openings must be
closed with plugs, which at least correspond to the protection class of the motor.
External fans and motors for use in explosion hazard areas have Ex labelling according to Directive 94/9 EC.
This labelling must be present on the external fan and on the motor. If the labelling of the external fan and
the motor differ, the lowest designated explosion protection applies to the entire drive. The maximum
specified temperature stated in the surface temperature data for the individual components applies for the
entire drive unit. In this context, it may be necessary to take into account any gear units that may be present.
Contact Getriebebau NORD if there are any doubts. If any component in the entire drive does not have an
Ex designation, then the entire drive may not be operated in an Ex area.
8.3 Return stop option
Motors with the additional labelling RLS (e.g. 80S/4 3D RLS) are equipped with a return stop. Motors with
return stops have an arrow marking the direction of rotation on the fan cover. The arrow points in the
direction of rotation of the motor. When connecting the motor and during motor control, it must be ensured
that the motor can only operate in the correct direction of rotation, e.g. by means of a rotary field test.
Switching the motor to the blocked rotation direction, i.e. incorrect rotation direction, can lead to damage.
Return stops operate without wear from a speed of approx. 800 rpm Return stops must not be operated at
speeds under 800 rpm to prevent impermissible heating and rapid wear of the return stop. This must be
taken into account for motors with a frequency of 50 Hz and poles
≥ 8, and for motors with frequency
inverters.