ATEX MAK Series Motor

This catalogue describes the main tech-nical characteristics of our Explosion-proof motors.

They have been designed according to ATEX N. 94/9/CE that concerns the es-sential safety characteristics of equip-ments intended to be used in poten-tially atmospheres.

The suitability of our explosion proof motors, to the essential safety charac-teristics demanded by the ATEX, is shown by the CE certificate issued by the CESI, notified body N. 0722.

An explosion and flame proof motor Exd, Ex de is a rotating machine which can work in an environment with the presence of gases and/or explosive or inflammable fumes without causing internal damage to the motor.
It is in fact:
Explosion-proof: its housing neither cracks nor explodes in case of an in-ward short circuit.
Flame-proof: it doesn’t allow the exit of gases and flame from the motor when the ambient temperature is critical.
Our motors has been certified for explo-sion group II A – IIB – IICand repro-duce the following identification marks:
GAS : ZONE 1 e 2 II 2G Ex d, Ex de
The standard EN 60079-0:2009 and EN 60079-1:2007,state the type of gases and vapours included in each explosion group (see the list in the bottom page).
Ex demotors = flameproof enclosure
“d” for motor frame and increased safety
“e” for terminal box.
DUST: ZONE 21 e 22 II 2D IP66 T 85
°C, T 100° C, T 125 °C, T 155 °C ac-cording with standard EN 60079-7:2007
Our motors are certified for the temper-ature classes T3 – T4 – T5 (some T6). The ATEX standard settles the corre-lation between temperature class and maximum motor surface temperature, according to the following table:


These characteristics are according to the following standards:


– size 56÷250
– housing, shields and terminal box in
cast iron
– standard mechanical protection IP55
– fan cover in steel sheet, protection
– the cooling fan is in non-sparking
synthetical material up to sizes 132
and in aluminium from size 160
– insulation class F and the temperature
rise of standard single-speed motors
within class B
– double enamelled cooper wire with
temperature index 200 °C (Class H)
– screws nickelled or cadmied
– stainless steel nameplate.
The rated output indicated on the name plate applies to continuous duty S1, rated voltage and frequency, to max 40 °C ambient temperature and to an altitude of installation up to 1000 metres above sea level.
Modifications of the output due to temperature and altitude changes are indicated in the following diagrams:euromotor-7
The motors can be wound up to supply voltage of 1.000V and 50Hz or 60Hz.

The motors can run with the variations envisaged in normal operational area: voltage of ±5% and frequency ±2%.

Furthermore, the motors can be used in the operational area with restrictions (with variations in voltage of ±10% and frequency from -5% up to +3%) as long as the indications given by norm 60034-1 are complied with.euromotor-8

euromotor-9According to IEC 60034-1 the electric data of the motors have the following tolerances:
In order to protect motor winding against thermal overloads during operation, the
motor can be provided with one of the following temperature dependent protec-tion devices:
1) Bimetal switches NC/NO
This device consist of 1 or 3 series con-nected protectors.The standard contact is closed/open; it opens/closes when the winding temperature reaches dangerous limits for the insulation system. This devices are suitable in the case of slowly rising winding temperature.euromotor-10

2) Thermistor temperature sensors PTC

It consists of 3 sensors series connected inserted into stator winding. One reached
the operating temperature,this device quickly changes the resistence; it must be connected to a suitable releasing device according DIN 44081-44082.

Motors for operation with invertors (fre-quency converter) are always supplied with PTC thermistor temperature sensors.


3) Thermometric resistors PT100
The resistence value of this devices var-ies according the winding temperature.

They are suitable for a continous survey of the winding temperature.

Motors equipped with PT100 are recom-manded for extra power short time operation, long time start-up, switching operation, reduced cooling air flow rates and high ambient temperatures.

Motors intended to use at low tem-peratures must be specially mentioned in the order.
Motors are certified for temparatures as low as -55 °C.
In order to keep inside the stopped mo-tor the minimum temperature of -20 °C, the motors are equipped with space heaters or the motors can be powered with low AC voltage via terminals U1-V1
(see below tables).
As an alternative to motor pre-heating, it is possible to use a special con-struction with suitable materials in low temperatures areas (-55 °C).

Anti-condensation heating
It’s possible to form condensation inside the motor due to temperature fluctuations.

To prevent this phenomenon,the motors must be heated using space heaters or low voltage power can be supplied to the winding via terminals U1-V1(see below tables).

It’s important that during the motor op-eration the space heaters are turned off


Motors with enclosures in protection type “d” or “de” are designed to work with feeding by means of a frequency convertor (inverter).

Euromotori designed and certified the motors Ex dand Ex deusing a conver-tor with a switching frequency above 3kHz (type PWM).

The motors supplied by converters and intended to be installed in rooms with atmosphere potentially explosive must be:

• explicitly required for this type of feeding
• appropriately selected according to load and speed range
• provided with appropriate passive thermal protection (thermistors, PTC, PT100)
• with plaque identifying the feeding by converter and the field in terms of use of torque, power, voltage and frequency or rotation speed.

When using a Ex dor Ex demotors with a frequency converter, the follow-ing points must be taken into account in addition to the general selection  criteria:
1) A motor fed by converter is subjected to a non-sinusoidal feeding (voltage, current) leading to increased additional losses, noise, vibration and insulation solicitations.

The increase of additional losses gen-erates an increase of motor heating and consequently the rise of bearings temperature. Of these effects must be taken into account (through an appropriate declassification compared to the mains supply) in particular for potentially explosive atmospheres as there are limits on the maximum surface temperature.

The increase of the magnetic noise de-pends mainly on the converter switching frequency and on the harmonic content.Self-cooled versions, with frequencies higher than the network, including the noise due to ventilation is increased about 3-5 dB (A) for frequency of 60 Hz and 8-9 dB (A) for 75 Hz compared the values given in the tables.

The insulation system of a motor is subjected to higher dielectric stress when using a frequency converter.According to the characteristics of the feeding system, it must be utilized filters dU/dt in order to ensure voltage peak of less than 1000V between terminals (motors with 500<Un<600V).

A particular attention must be paid for motors with long feeding cable between the frequency converter and the motor or in the case of rated voltage of 690 V: the motor insulation must be strength-ened due to voltage peaks.

2) In a frequency converter drive the actual operating speed of the motor may deviate considerably from its rated speed. For higher speeds it must be ensured that the highest permissible motor rotation speed, or the critical speed of the entire equipment, is not exceeded. In addition, bearing lubrifica-tion will require special attention.

3) A motor with rated voltage 400V, 50Hz with a star connection, can be used in constant torque up to the frequency delta connection of 87Hz.In this case, the power of converter must be greater than 1.73 times the rated power of the motor and the converter configured to provide 230V at the frequency of 50Hz.

4) It must use cables and connections in accordance with requirements under the EMC (electromagnetic compat-ibility). The feeding cables must be symmetrical and insulated. The grounding of the motor and of the operated system must be properly done in order to avoid possible tensions and currents on motor bearings.
The additional instructions provided by the manufacturer’s converter should be followed.
The performance of 2 and 4 poles motors using a frequency converter (constant torque and quadratic torque) are given in specific tables together with the loadanility curves. For motors of 6 and 8 pole take the advice of EUROMOTORI.

Low voltage induction motors, if in-stalled correctly and connected to the power supply, respect all immunity and emission limits as set out in the regulations relating to electromagnetic compatibility (EMEC “Generic Standard”
for industrial environments).

In the case of supply by means of elec-tronic impulse devices (inverters, soft starters, etc.), all verifications and any modifications, necessary to ensure that emission and immunity limits, as stated within the regulations, are respected and are the installer’s responsibility.

The standard motors are are equipped with deep groove ball bearings series ZZ both at driving and non driving end. Upon request, open deep groove ball and roller bearings with lubricators can be fitted at drive end from frame size 160.

The ZZ series bearings are lubricated for life and require no further lubrication.
Open bearings are supplied with lubri-cators and are to be lubricated accord-ing to the indications given in the table.When assembling ball bearings on both sides the bearings are axially preloaded. A dust seal is fitted in drive and non drive end shields. This avoid water and
dust travelling along the shaft and penetraiting into bearings housing.euromotor-16


– Motors tropicalised
– Class H motors
– Mechanical protection IP 66
– Mechanical protection IP 56
– Special voltage and frequency mo-tors
– Two speed motors, standard or for
fan drive
– Motors suitable for frequency con-verter driving
– Motors with tacho generator or en-coder
– Motors with special shaft and flange
– Single-phase motors
– Single-phase high-torque motors
– Torque motors
– Motors for ambient temperature up
to -55°C
– Motors for ambient temperature
up to +80 °C