Drives and Controls Magazine
Ex-rated IE4 motors are ‘world’s first’
Published:  15 April, 2013

At the recent Hannover Fair, Bauer Gear Motor launched what it claims is the world's first Ex-rated, IE4 super-premium efficiency geared motor. It adds that the S Series PMSMs (permanent magnet synchronous motors) are the world's most efficient motors for use in explosive atmospheres.

Motors for use in hazardous areas are exempt from the EU regulations on minimum efficiencies because explosion protection takes precedence over energy savings. This has put industry sectors such as oil, gas and mining, at a disadvantage when trying to improve the efficiency of their operations. While safety has to be a priority, the EU exemption has meant that operators are missing out on potential energy savings of up to 40%.

The launch of Bauer’s new IE4 motors means that applications which require motors to be specified and designed to Atex classifications can now benefit from similar energy savings as found in other sectors.

Currently, most Ex e (Increased Safety) rated variable-speed three-phase induction motors on the market have basic IE1 efficiency ratings. While the efficiency of these can be improved by adding frequency inverters, they still fall well short of IE3 and IE4 efficiencies.

The S series motors span ratings from 0.55–15kW and are classified for use in Zones 1 and 21. They offer the added benefit of maintaining constant speed independent of the load. This means that motor speeds do not vary, despite overload variations or voltage drops, as long as the mains frequency is kept constant.

PMSMs offer improved efficiencies compared to induction motors even under partial load conditions, and extremely high efficiencies under rated operating conditions. They also have much higher power densities, which, for geared motors, yields higher system efficiencies, smaller installation volumes and reduced weights.

The motors can produce higher torque values in the same volume than conventional induction motors, allowing users to specify smaller motors in some applications.