Ex ec and Ex tc motors (Zone 2 and Zone 22)

MENZEL offers you a wide selection of low, medium and high voltage motors for potentially gas and dust explosive industrial areas.

MENZEL Ex ec (former Ex nA) and Ex tc motors are used in potentially explosive industrial environments around the world, and must therefore sufficiently meet the highest standards for the safety of man, machine, and the environment. MENZEL offers a wide range of increased safety motors for Zone 2 (Ex ec) and dust ignition proof motors for Zone 22 (Ex tc). Our Ex ec and Ex tc motors are tailor-made with low, medium or high voltage, and are ideally suited for particularly demanding uses and applications. They are available not only with squirrel cage rotors, but also as special designs with slip ring motors.

MENZEL explosion-proof three-phase motors boast particularly robust and high-quality motor construction. Our ex motors have an optimal level of efficiency and are typically used in compressors, gas and steam turbines, ventilators, pumps, mixers and agitators.

All MENZEL Ex ec motors and Ex tc motors fulfill the current European ATEX guidelines.

Technical data on Ex ec (former name: Ex nA) motors for Zone 2 – increased safety

Equipment group II, Category 3G
Explosion group: IIC (easily flammable gases or vapor mists)
Equipment protection level: Gc (for seldom, short-term explosive atmospheres)
Temperature classes: T1, T2, T3 up to 200°C
Power range: from 55 kW to approx. 5,000 kW
Voltage: up to 13.8 kV (for 50 and 60 Hz)
Common construction types: IM B3, IM B5, IM V1, IM B35
All standard sizes
Various protection classes and cooling types

Technical data on Ex tc motors for Zone 22 – dust explosion protection

Equipment group II, Category 3D
Dust group: III (non-conductive dust)
Equipment protection level: Dc (for occasional, short-term explosive atmospheres)
Max. surface temperature: up to 125°C
Power range: from 55 kW to approx. 5,000 kW
Voltage: up to 13.8 kV (for 50 and 60 Hz)
Common construction types: IM B3, IM B5, IM V1, IM B35
All standard sizes
Various protection classes and cooling types

MENZEL Ex ec and Ex tc motors – the advantages at a glance:

Optimal level of efficiency

Optimal safety

Energy efficiency

Robust housing

Operational safety

Serviceability

Can be delivered directly from the warehouse in the event of an emergency

Requirements for explosion-proof motors

For explosion-proof motors, increased demand is placed on the mechanical construction and its layout, the dimensions of the electrical insulation system, and protection against inadmissible heating.

For explosion-proof motors which are fed by a frequency inverter, other risks concerning the two ignition sources, such as “electrical discharges” and “hot surfaces” must be considered when designing and certifying the machinery.

Explosionproof motor with frame size 400

Slip ring motor for zone 22 hazardous area

Motors for Zone 2 (gas) and Zone 22 (dust)

The division of potentially explosive areas into so-called zones is carried out according to the frequency and duration of the occurrence of dangerous, potentially explosive atmospheres.

Zone 2 identifies areas in which explosive atmospheres are rare in normal operation, and even then their presence is only very brief. MENZEL electric motors for Zone 2 correspond to the requirements for equipment category 3G.

The construction of our Ex ec motors and the use of special materials and connectors prevents the occurrence of arcs, sparks or hot surfaces during normal operation. The risk of sparking is therefore eliminated. All components inside the electric motor correspond to the temperature class for which the motor has been approved.

Zone 22 identifies areas in which explosive atmospheres (in the form of a cloud) are rare in normal operation, and even then their presence is only very brief. A layer of dust, just one millimeter thick, can be enough to turn an entire room into an explosive atmosphere when it is circulated.

MENZEL electric motors for Zone 22 correspond to the requirements for equipment category 3D. When designing Ex tc motors, meticulous care is taken to ensure that the temperatures of the motor surfaces, on which dust can accumulate, remain below the temperatures stated in the Standard. Special seals on cables and terminal boxes prevent the penetration of dust.

Typical areas of application for Ex tc motors (Zone 22, dust)

Ex tc motors are typically used where easily combustible dust develops, such as in grain mills (danger of grain explosion).

Food industry
Sugar refineries
Grain mills
Silos
Lumber industry
All other industrial sectors with potentially explosive areas

Typical areas of application for Ex ec motors for increased safety (Zone 2, gas)

MENZEL non sparking electric motors are typically used in potentially explosive industrial environments. They are characterized by particularly aggressive atmospheres, extreme temperatures, and high safety standards.

Oil and gas industry
Chemical and petrochemical industry
Onshore and offshore
All other industrial sectors with potentially explosive areas

Example reference projects

Slip-ring motor for coal mill drive application in Ex zone 22 hazardous area

Slip-ring motor for Ex zone 22 hazardous area

High Voltage MotorsEx nA and Ex tc motorsSlip ring (IC 611 + IC 616 + IC 666)Motors for hazardous areas

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Squirrel cage motor for oil refinery (Sweden)

3000 VEx nA and Ex tc motorsSquirrel Cage (IC 411 + IC 416)Motors for hazardous areas

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ATEX guidelines for Ex ec and Ex tc motors

The standardized guidelines and requirements for working in potentially explosive atmospheres (atmosphere explosible – ATEX) have been defined in all EU Member States. ATEX Product Directive 2014/34/EU applies to manufacturers. This is the successor of the previously applicable Product Directive 94/9/EG. They are the basis for certification.

MENZEL explosion-proof three-phase motors comply with European Directive 2014/34/EU (ATEX) for increased safety “ec” (Ex ec IIC) and dust ignition protection “t” (Ex tc IIIB). They are certified in accordance with ATEX, through an EU Declaration of Conformity.

Our customers receive a detailed test report, relevant test protocols and Ex protection documents along with their MENZEL Ex ec and Ex tc motors. TÜV approval is optional.

Example for TÜV Nord Third Party Declaration (pdf, 567 KB)

In Annex II, 1.0.5 of ATEX directive 2014/34/EU, it is recommended that the Ex motors are labeled as follows:

“Ex mark” ATEX-Logo (epsilon chi in a hexagon)
Equipment group (e.g. “II”: all other areas)
Equipment category as defined in the ATEX directive (1G, 2G, 3G, 1D, 2D, 3D)
Labeling according to the applicable Standards

The letter “G” stands for gas, and “D” stands for dust.

MENZEL increased safety and dust ignition proof motors are labeled directly on the motor housing, in accordance with the ATEX guidelines. The equipment category indicates in which Ex protection zone the electric motor can be installed. In addition to the protection class and the equipment category, the usability within a particular gas category and the maximum surface heating of the electric motor are also stated on the identification plate.

Example: II 3G Ex ec IIC T3 Gc

In other words: The Ex motor is to be used above ground, in Gas Zone 2, non sparking, and is suitable for all gases which have been classified as GII (explosive gases/dust clouds), and which can tolerate a maximum surface temperature of 200°C. Can be used in rarely or temporarily potentially explosive atmospheres.

The arrangement of temperature classes occurs in classes T1 to T6, whereby ascending numbers indicate lower surface temperatures.

Temperature classes	Maximum surface temperature
T1	450°C
T2	300°C
T3	200°C
T4	135°C
T5	100°C
T6	85°C

Potentially explosive gas areas

Zone 0
This is an area in which there is a temporary or permanent potentially explosive atmosphere due to a mixture of air and combustible substances (gas, steam or mist).
Zone 1
This is an area in which a potentially explosive atmosphere is expected during normal operation, due to a mixture of air and combustible substances (gas, steam or mist).
Zone 2
This is an area in which a potentially explosive atmosphere is not expected during normal operation, due to a mixture of air and combustible substances (gas, steam or mist). Even then, the presence of this atmosphere is rare and very brief.

Potentially explosive gas areasAreas with combustible dust

Zone 20
This is an area in which a potentially explosive atmosphere is present – either permanently, in the long-term, or frequently – in the form of a cloud of combustible dust in the air.
Zone 21
This is an area in which a potentially explosive atmosphere is occasionally present in the form of a cloud of combustible dust in the air, during normal operation.
Zone 22
This is an area in which the presence of a potentially explosive atmosphere, in the form of a cloud of combustible dust in the air, is not expected during normal operation. If such an atmosphere is present, however, its presence is only temporary.

Are you looking for an electric motor for Zone 2 or Zone 22? We have the right Ex ec or Ex tc motor for you!

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