High efficiency motors are safe for dusty duties

Edited by the Engineeringtalk editorial team Nov 6, 2006

WEG has extended its ATEX range of high efficiency electric motors for hazardous applications with the introduction of dust ignition proof (DIP) motors for use in ATEX Zones 21 and 22.

WEG has extended its ATEX range of high efficiency electric motors for hazardous applications with the introduction of dust ignition proof (DIP) motors for use in ATEX Zones 21 and 22.

The motors are designed to operate safely and save energy in environments where explosions can occur due to combustible dust.

Typically these environments are found in sugar refining plants, breweries, cement works, textiles, and pharmaceutical, chemical and agricultural process industries.

The WEG high efficiency DIP ranges are designed in accordance with the requirements of IEC and Cenelec Standards, and with the ATEX Directive 94/9/EC: Categories Ex II 2 D T125oC (Zone 21) and Ex II 3 D T125oC (Zone 22).

In addition, the Zone 22 motors offer the added benefit of operation in gas Zone 2 (Ex II 3 G EEx nA II T3).

This means that that one motor will suffice in atmospheres containing both combustible gas and nonconductive combustible dust.

Offering the highest level of safeguarding of the new introductions, the Zone 21 DIP motors are third party certified and offer the highest level of ingress protection on the market: IP66.

These motors are designed to operate in areas where flammable dust can be released, or atmospheres where explosions can occur due to a mixture of air and dust being present.

Complementing the Zone 21 motors for less critical applications, the Zone 22 range is IP55 rated - upgradeable by WEG to IP66, where required.

It is designed for environments, where nonconductive flammable dusts may occur frequently and be present for short periods of time.

Constructed with robust cast iron housings in frame sises 63 to 355M/L, the new DIP motors are rated for three-phase operation at both 50 and 60Hz, in output ranges up to 355kW.

Both ranges are available in two-, four-, six- and eight-pole configurations, benefit from Class F insulation with Class H winding wire as standard, and are suitable for use with variable speed drives (VSD).

As regards inverter use, the insulation system of all WEG's range of hazardous area motors - gas or dust - is highly efficient in dealing with the higher peak voltages and faster voltage rise times generated by the IGBTs (high dV/dt) used in the latest generation of VSD.

However, as an added safeguard to diminish the risk of excessive surface temperatures, thermal protection of DIP motors is incorporated as standard in the form of PTC thermistors in the motor windings.

In cases of over-temperature, the output from the thermistor initiates a relay, which removes the power supply to the motor, effectively turning it off.

In addition to the high levels of safeguarding they provide, WEG's new DIP range incorporates high efficiency machines that either meet or exceed CEMEP/WIMES requirements.

Premium Efficiency types meet the requirements of CEMEP's/WIMES Eff1 level, and the Top Premium Efficiency Eff1+ units comfortably exceed these requirements.

In addition, WEG also offers EExd/EEx de high efficiency motors in premium efficiency ratings up to 400kW for use in general hazardous environments.

All of these motor types are registered with DEFRA to enable users to claim enhanced capital allowances (ECAs) on the motor purchase - a substantial contribution to reducing payback times.

WEG offers the market the most comprehensive and graduated range of ATEX Compliant electric motors for use in the widest variety of dust laden or gaseous atmospheres.

In addition to the dust ignition proof ranges described above, the following gas compliant classifications are included in the WEG low voltage product range: EEx d/EEx de IIA, IIB and IIC (explosion proof), EEx nA, (non sparking) and EEx e (increased safety), which offer the user and OEM the ultimate flexibility in both application specification and cost.

Complementing this flexibility is the wide range available: ratings up to 1120kW and frame size 500 - in standard two-, four-, six- and eight-pole configurations.

Completing the WEG Hazardous Area offering is a comprehensive range of MV/HV machines in EEx d/EEx de, EEx p and EEx nA variants in multiple polarities and power ratings.