Motors for Hazardous Areas

TYPES OF MOTORS 

The following are the main groups of motors used in hazardous locations, but not all situations are covered. Should you have an application not covered by the following, please refer to one of our sales offices.

  • Ex d flameproof motors for industrial use
  • Ex e increased safety motors
  • Ex n non-sparking motors
  • D.I.P. dust ignition proof motors 

COMPLIANCE TO STANDARDS 

  • All motors suitable for use in hazardous areas are manufactured/modified in strict accordance with the conditions required by the relevant standards and the issued Certificate of Compliance and are fully tested prior to despatch by the manufacturer. 

SELECTION OF MOTORS FOR USE IN HAZARDOUS AREAS 

  • There are a number of defined hazardous areas covering gases and dusts. It is therefore strongly recommended that all relevant SABS 0108 Standard be consulted prior to final selection of the motor.

HAZARDOUS AREAS 

  • Many gases, vapours and dusts which are generated, processed, handled and stored in industry are combustible.
  • When ignited they may burn rapidly and with considerable explosive force if mixed with air in the appropriate proportions.
  • Areas where gases, vapours, dusts and fibres occur in dangerous quantities are classified as HAZARDOUS.

Classification of areas are: -

  • gases, vapours, mists - Class I
    dusts - Class II

Gas groupings are further defined for either: -

  • coal mining (methane) - Group I
  • other industries - Group II
  • With Group II gases, they are further subdivided into sub-groups IIA, IIB, IIC, depending upon the ignition point of the gas.
  • ZONAL CLASSIFICATION is also required where explosive gas atmospheres are present and they indicate the probability of the presence of a flammable, combustible or explosive material, the extent, dimension and shape of the hazardous areas, together with the volume in which the hazardous material can be expected.

There are three zones: -

  • ZONE 0 - An area in which an explosive gas atmosphere is continuously present or is present for long periods of time.
  • ZONE 2 - An area in which a gas atmosphere is not likely to occur in normal operation and if it does occur, it will exist for a short period only. 

TEMPERATURE CLASSIFICATION 

  • Hot surfaces can cause ignition of gases, vapours and dust; therefore it is necessary to ensure that the maximum surface temperature of equipment introduced into a hazardous area does not exceed the ignition temperature for the gas, vapour or dust in the hazardous area.
  • Group I Gases - Maximum Surface Temperature 150°C
  • Group II gases and Class II dusts are given a Temperature Class (T) based on the maximum surface temperature of the equipment.

Temperature Classes are:-

  • T1 - 450°C
  • T2 - 300°C
  • T3 - 200°C
  • T4 - 135°C
  • T5 - 100°C
  • T6 - 85°C

Note:

  • For Ex d flameproof apparatus, the external surface is the measured surface.
  • For other types of protection (e.g., Ex e) internal surfaces are of equal importance if the explosive atmosphere has access to them.  

EXPLOSION PROOF MOTORS Ex e, INCREASED SAFETY 

Standard three-phase motors

  • These motors are certified to Ex e and can fit a wide range of products as shown throughout the catalogue.
  • These motors are certified to Ex e Class 1, Zone 1 protection.
  • The certificate covers gas groups IIA, IIB and IIC, temperature classification T3 and enclosure protection IP66.
  • The Standard complied with is AS2380.1:1989.
  • his Standard means the motors are also suitable for Ex n and DIP applications.

ELECTRICAL AND MECHANICAL SPECIFICATION 

  • Voltage: Up to 500 Volts
  • Insulation: Class 'F'
  • Enclosure: Totally enclosed, fan-cooled
  • Degree of Protection: Up to IP66
  • Frequency: 50 or 60 Hz 

LIMITING TEMPERATURE 

  • The temperature of an external or internal surface to which the surrounding atmosphere has access, shall not exceed the LIMITING TEMPERATURE specified. 

RANGE 

  • It is possible variations will arise in the kW/frame size/rpm, from one manufacturer to another from that normally referred to in normal motor standards. 

FANS FOR Ex d AND Ex e APPLICATIONS 

  • Fans for Ex d and Ex e applications, or indeed any hazardous application, can be constructed of special materials and incorporate special features.
  • Anti-static impellers and earthing leads are just some of the features we can provide. 
 
Download pdf file 
 

TDE

The Multiflow TDE 500 to 710 range consist of fully cased, cylindrical models with circular mounting flanges at both ends and a wired terminal box.

RVF

The Mini Centrifugal Roof Fan series are the new type roof extract units available in 2 sizes and suitable for vertical and horizontal installation. The low noise external motor and high efficient backward bladed impeller meets the requirement of efficient ventilation in residential, commercial and light industrial applications.

Future 150

The Decor Series can be wall or ceiling mounted and is designed to exhaust stale and moist air from bathrooms, toilets, laundries etc. They are also suitable for ventilating all types of small or closed areas.

TD Silent

The Silent Series is a low profile mixed-flow in-line fan that produces low noise when in operation. It does this through a specifically designed perforated internal skin that directs sound waves produced inside the fan to a layer of sound absorbent material.

NEW!! TD-EVO

The low-profile TD-EVO 250 and 315 in-line mixed-flow fans for circular ducts have a unique design where the support bracket allows the motor and impeller assembly to be fitted or removed without dismantling the adjacent ducting.

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