Marek Lukaszczyk discusses gearbox considerations for hazardous environments

Mines and quarries are subject to strict regulations F

ew industries have stricter regulations than mining, quarrying and oil and gas. When operating in hazardous environments, meeting

regulation is critical – and the parts and components used inside these industries is no exception. T ere are several requirements for ATEX-certifi ed geared motors. If you are planning to use a geared motor in a hazardous environment – that includes any explosive atmospheres caused by fl ammable gases, mists, vapours or combustible dust – it is vital that ATEX directives are adhered to. ATEX is the name given to two

European Directives for controlling explosive atmosphere. Directive 99/92/ EC, sometimes referred to as ATEX 137 or the ATEX Workplace Directive, focuses on the protection of workers. Directive 94/9/EC was developed to improve the safety of equipment used in explosive atmospheres. T is is referred to as the ATEX Equipment Directive. Operators working in hazardous atmospheres must comply with these directives at all times; not only when operating on site, but also when selecting machinery, parts and components, such as gearboxes and motors. Hazardous atmospheres are classifi ed

in zones. T ese zones distinguish between places that have a high chance of an explosive atmosphere developing

and those places where an explosive atmosphere may only occur occasionally or in abnormal circumstances. T is classifi cation not only aff ects the health and safety guidance for workers in these areas, but also the equipment that can be used and how it should be mounted and installed.

Consider a gearbox as an example. In

accordance with Directive 2014/34/EU, the WEG WG20 range of ATEX-certifi ed geared motors has been specifi cally designed to use in explosion-protected areas: category two in zone 1/21 and category three in zone 2/22. However, there are installation diff erences for diff erent hazardous atmosphere zones.

MOUNTING GEARED MOTORS For geared motors in zones 2/22, the motors can be mounted directly but for zones 1/ 21, an adapter is required. Mounting geared motors can reap technical benefi ts and is also a straightforward process. Market standards have dictated certain fi tting dimensions for geared motors, so it is advantageous to select a geared motor that is fully compatible with these standards. For WEG, designing motors to this

standard ensures plant managers do not have to modify their systems and allows machine manufacturers to retrofi t their existing equipment without any major modifi cations.

Should an adaptor be required – for applications in hazardous zones one and 21, for example – machine manufacturers can use the adaptor to combine the gearbox with other equipment. For instance, the entire range of WG20 gear units can be combined with explosion- proof WEG IEC energy effi cient motors using this method. Overlooking these requirements can

result in dire consequences for machine manufacturers serving the mining sector. Not only does adhering to ATEX regulations protect the manufacturer from non-compliance, but incorrect equipment used in these sectors can also be incredibly dangerous – hence the stringent regulations associated with the markets.

WG20 motor series

Marek Lukaszczyk is with WEG 27

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