Specification Sheet

Installation & Operation 2−9MN408
Flameproof motors, internationally referred to as Ex d use a protection concept similar to that used in
Class I Division 1 motors, with minor differences in the flameproof joints and cable entry designs.
Flameproof and explosion proof motors are both type tested. Representative motors are connected to a
reference gas and ignited in laboratory conditions to verify that the flame is not transmitted outside the
motor enclosure and to determine the maximum internal pressure encountered.
Explosion proof and Flame proof motors shipped without a conduit box require use of a certified box of
suitable dimensions and that is appropriate for the classification. Openings in connection boxes must be
closed with suitably certified and dimensioned device.
Class I Division 2 / Zone 2 Ex nA, [Equipment Protection Level (EPL) Gc ]
This protection concept relies on having no sources of ignition present such as arcing parts or hot
surfaces. For this protection concept, internal temperatures as well as external temperatures are
considered. In many cases, the internal temperatures are higher than the external temperatures and
therefore become the limiting factor in determination of temperature code designation. In these
applications, it is very important to use a motor that has been evaluated thermally for use with an inverter
or converter, if variable speed operation is desired. Thermostats used for Class I Division 2 and Ex nA
motors are used to protect the motor only. For motors using flying lead construction, it is important to use
connection lugs and insulate with heat shrink tubing or a double wrap of insulation grade electrical tape to
avoid the risk of spark or ignition.
Class II Division 1 / Zone 21 [Equipment Group III, Equipment Protection Level (EPL) Db ]
This area classification is one where the risk of ignitable concentrations of dust is present at all or some of
the time. The protection concepts used for Class II Division 1 is similar to flamepath, except with
additional dust exclusion paths designed for the rotating shaft. In the international designations, this
concept is referred to as dust ignition proof or Ex tD. External surface temperature remains the limiting
factor. Thermal limiting devices such as thermostats, thermistors or RTDs may be provided on these
motors to limit the external surface temperature during overload conditions. If thermostats are provided
as a condition of certification, it is the installer’s responsibility to make sure that these devices are
properly connected to a suitable switching device.
Note: In the North American area classification system, Class III exists for fibers and flyings.
In the IEC designation, both dusts and flyings are absorbed into Group III.
Class II Division 2 / Zone 22 [Equipment Group III, Equipment Protection Level (EPL) Dc ]
This area classification is one where the risk of exposure to ignitable concentrations of dust are not likely
to occur under normal operating conditions and relies heavily on the housekeeping practices within the
installation.
Sine Wave Power Operation for Division 1 or 2 and Zone 1 or 2 and Zone 21 or 22 Hazardous
Location.
These motors are designed to operate at or below the maximum surface temperature (or T−Code) stated
on the nameplate. Failure to operate the motor properly can cause this maximum surface temperature to
be exceeded. If applied in a Division 1 or 2 / Zone 1 or 2 and Zone 21 or 22 environment, this excessive
temperature may cause ignition of hazardous materials. Operating the motor at any of the following
conditions can cause the marked surface temperature to be exceeded.
1. Motor load exceeding service factor nameplate value
2. Ambient temperatures above nameplate value
3. Voltages above or below nameplate value
4. Unbalanced voltages
5. Loss of proper ventilation
6. Altitude above 3300 feet / 1000 meters
7. Severe duty cycles of repeated starts
8. Motor stall
9. Motor reversing
10. Single phase operation of polyphase equipment
11. Variable frequency operation
Variable Frequency Power Operation for Division 1 or 2 and Zone 1 or 2 and Zone 21 or 22
Hazardous Location (motors with maximum surface temperature listed on the nameplate).
Only motors with nameplates marked for use on inverter (variable frequency) power, and labeled for
specific hazardous areas may be used in those hazardous areas on inverter power. The motor is
designed to operate at or below the maximum surface temperature (or T−Code) stated on the nameplate.
Failure to operate the motor properly can cause this maximum surface temperature to be exceeded.