Motors future-proof against new safety standards

Leroy Somer electric motors are future-proof against new safety standards for explosive atmospheres, says the company.

In three years time the European Union ATEX Directive will introduce higher standards of protection for electric motors used in explosive atmospheres.

Leroy Somer's FLSD, FLSN, FLSPX and LSPX ranges have been designed to satisfy the requirements of this Directive, enabling operators of installations with hazardous environments to meet tomorrow's safety standards today.

The European Union's ATEX Directive 94/9/EC, "Protective devices and systems designed for use in explosive atmospheres", lays down new standards of protection for equipment used in atmospheres where the presence of dust or gas presents a risk of explosion.

It must be implemented by all EU member states on 1 July 2003 and will apply to existing as well as new installations.

Installing the appropriate motor from Leroy Somer's extensive hazardous areas range enables operators of installations with potentially explosive atmospheres to prepare for this Directive.

The ATEX Directive will introduce statutory minimum standards across the EU for the first time, though individual member states will still be able to introduce national standards that go beyond the Directive.

The ATEX Directive requires operators of hazardous installations to carry out a risk assessment and classify areas where there is a risk of explosion into three zones.

Equipment, including electric motors, is categorised according to its level of protection against becoming a source of ignition, and the ATEX Directive specifies which category of equipment may be used in each zone.

Equipment designed and constructed to comply with the Directive must be CE marked and carry a special mark consisting of the Greek letters "Ex" enclosed in a hexagon.

Depending on the category, either the manufacturer or a third party authority has to certify that the product meets the necessary standard.

Zone 20 and Zone 0 are areas where there are combustible dust or gas clouds respectively, frequently or permanently.

Only Category 1 equipment is permitted in Zones 20 and 0, and no electric motors can be used in these zones.

Zone 21 and Zone 1 are areas where, during normal operation, the atmosphere very occasionally consists of combustible dust or gas clouds respectively.

Equipment in these areas must meet or exceed the requirements of Category 2.

Category 2 motors must be CE marked and a certificate of conformity issued by a certified authority.

Motors for use in Zone 21 must additionally be rated IP6x and the surface temperature cannot exceed 125øC, the lowest temperature at which a cloud of wheat or other cereal crop dust could ignite.

Leroy Somer's new LSPX and FLSPX ranges comply with all the requirements for use in Zone 21.

They are rated IP65, the highest for protection against ingress of dust, the surface temperature is guaranteed not to exceed 125C and they are third party certified by INERIS.

These motors are painted orange to distinguish them from conventional non-Ex motors.

Leroy Somer's flameproof FLSD range is suitable for use in Zone 1.

To ensure the motor surface temperature never reaches a level that could ignite a gas cloud, thermal probes are incorporated into the coils and/or endshields of the motors.

These are then connected to a thermal protection device that shuts off the motor if the temperature rises above a pre-set limit.

Zones 22 and 2 cover areas where the atmosphere either does not consist of combustible dust or gas clouds or only consists of such clouds for a very short duration.

Motors in this zone must be Category 3 equipment and CE marked, though the manufacturer is allowed to self-certify compliance with these specifications and no third party certification is required.

Motors for use in Zone 22 must be rated IP5x and the surface temperature must not exceed 125C.

The Leroy-Somer LS and FLS ranges can be installed in Zone 21 when used with the SILO option.

Built to this specification they are rated IP55 and maximum surface temperature does not exceed 125C.

The FLSN non-sparking range is suitable for use in Zone 2.

These motors are designed so that the temperature at any point, including the rotor, cannot exceed set limits under any operating conditions, and these limits are shown on the conformity certificate and the nameplate.

FLSD, FLSN, FLSPX and LSPX motors are available in a range of frame sizes with a variety of options including variable or dual speed and FAP brakes.

With the Leroy Somer ranges of explosion-proof motors operators and OEMs can future-proof installations with explosive atmospheres against impending legislation.

Specifying ATEX-compliant motors between now and 2003 will ensure that equipment does not have to be replaced to comply with the regulations when they come into force.

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