A new series of flameproof explosion-proof motors (according to ATEX) in the IE3 efficiency class

The global trend of reducing emissions of harmful gases, which are a side effect of energy production processes (e.g. from coal), is the main stimulus to search for new energy sources (including renewable sources) and to improve current industrial equipment and processes in order to reduce the consumption of energy produced. An additional factor determining the above-mentioned operation is a significant increase in the demand for electricity in relation to the production capacity.

Taking into account that about 50% of electricity produced for example in Poland is used by drive systems with electric motors, the use of energy-saving drive systems with high-efficiency electric motors may bring significant effects in reducing the above-mentioned negative effects of the development of our country while ensuring measurable savings for the user.

Until 2021, the requirements for the minimum level of efficiency of motors placed on the EU market did not cover explosion-proof motors, for which the only obligatory aspect of the design was to ensure an adequate level of safety for users in the potentially explosive zone.

The new Regulation of the European Commission 2019/1781 & 2021/341 introduces revolutionary changes in the above scope. From July 1, 2021, all explosion-proof motors, with the exception of mining motors intended for operation in underground mines and motors of reinforced construction, must meet the requirements for the IE3 efficiency class.

CELMA INDUKTA S.A. (member of Cantoni Group) is a long-term manufacturer of a wide range of three-phase electric motors, including explosion-proof motors for the mining and chemical industries. The first motors of our production for hazardous areas were put into production in the 1950s.


Taking into account over 70 years of experience in the production of Ex motors and in regard of the new minimum efficiency requirements resulting from the Commission Regulation (EU) 2019/1781 & 2021/341, CELMA INDUKTA S.A. designed from scratch and then approved a new series of Ex db (eb) flameproof motors in the range of 90 ... 315 intended for the chemical industry in the IE3 efficiency class - series (E)cSTe(b).

The design of the new (E)cSTe(b) series motors was developed on the basis of the latest global trends in the field of explosion-proof motors and in consultation with our customers submitted to the previously produced (E)cSg series:

  • approved for gas group IIC (also meets the requirements for groups IIA and IIB) with temperature class T5 or lower,
  • non-contact seals of bearing nodes for the size range 160 ... 315,
  • modernized bearing nodes to ensure long life of the bearings,
  • bolted connections of the bearing shields with the frame,
  • available version with a separate auxiliary box for additional equipment (e.g. temperature sensors, heaters, etc.),
  • optimized cooling system to limit winding and bearings temperatures, thus increasing the MTTF time (mean time to failure),
  • a wide range of accessories (independent cooling, encoder, brake, etc.)
  • and variants of execution (for power supply from a frequency converter, for low temperatures, for dust environments, with a special shaft seal for operation with the shaft upwards without a raincover, etc.),
  • possibility of Y / D switching inside the terminal box.

The motors have valid approvals according to international requirements for explosion-proof devices.