One of the special areas of focus for CG has been motors for hazardous area applications. The scenario of operation of these motors and the regulatory requirements are both complex. They are also constantly changing with the introduction of new European and Indian standards. We keep abreast with the latest developments to ensure that all the products fully comply with relevant regulations.

Flameproof Induction Motors
(Ex ‘d’ for ZONE-I, II – Gas Group IIA, IIB)

The essential principle of electrical apparatus with flame proof enclosure is that the hazardous atmosphere is not excluded from entry into the enclosure. It is recognized that an explosion is likely to occur within the apparatus but the construction of the enclosure should be such that it shall withstand the internal explosion without any evidence of distress and shall prevent the communication of the internal ignition to the surrounding atmosphere (the term flame proof as used here is synonymous with the term “explosion proof” as used in the USA or “Explosion Proof type ‘d’ protection” used in Germany and other continental countries)


  • Resin pour insulation system with VPI using solvent-less epoxy resin.
  • Die penetration and ultrasonically tested rotor shafts.
  • Two stage dynamic balancing of rotors complying with Grade 2.5 of ISO: 1940.
  • Copper/copper alloy bars tight fitted in slots and brazed to short circuiting ring.
  • Grease lubricated ball /roller bearings.
  • Oil lubricated sleeve bearings to withstand high speed and heavy load


Up to 2000 kW Up to 6600 V 355 to 710 IEC, IS


Stator frame has a barrel type construction made from thick fabricated steel to withstand internal pressure. Stringent checks like pressure tests are in place to ensure to high degree of welding quality. Adequate care is taken during machining to ensure a perfect concentricity of stator bore leading to minimum vibration level and optimum heat transfer. For higher frame sizes i.e. 630 and 710 the frame is of TETV construction. The tubes are double expanded in thick end plates to provide protection against leakage in case of explosion.

Technical Specifications

Degree of Protection : IP55
Enclosure : IC 411 / IC 511
Dimensions : As per IEC: 60072-A
Output : Up to 2000kW
Supply Voltage : 415, 690, 3300, 6600
Supply frequency : 50, 60 Hz
Mounting : IMB3, IMV1, IMB35
Frame Size : E355, E450, E560, E630*, E710*