The LOHER "non-sparking motor" - predestined for use in hazardous Zone 2

General description

Loher is using this motor type to increasingly address large oil & gas projects (in addition to the standard business) - for example the industrial plants located in the huge gas fields in Qatar. The reason for this is that also here the design allows the motor to be individually adapted to the particular application, so that even extremely complex customer specifications can be fulfilled without any deviations. Further, the advantages include the low motor weight and the extremely simply motor installation and maintenance. LOHER Ex nA motors also have optimized parameters, i.e. the winding and rotor are optimally adapted to the environmental conditions. Only then can the optimum values for efficiency and power factor be achieved (without derating). The result is reflected in the energy saving with the lowest load on the line supply. A sensible investment for the future.
These motors are available up to approx. 315 kW. In addition to the usual types of construction (where the shaft and flange is also in conformance with NEMA), non-standard numbers of poles, pole-changing versions, high-speed designs as well as special cooling types are available - precisely to customer specifications. Our strengths also include special voltages / special frequencies / special insulation / converter operation.
Versions with special bearing designs for extremely high radial or axial (thrust) forces are especially worth noting.


Technical data overview

Brief overview


1PS1 (LOHER CHEMSTAR) Loher name: A…K

Shaft heights:

Frame sizes 071 - 355 mm (area of standard motors)

Power range :
(50 Hz types)

Up to 315 kW (thermally utilized according to temperature class B at TU = 40 °C)

Number of poles:

2 - 12 pole; also higher numbers of poles for special versions
pole changing
- 2 speeds e.g. 4/2, 8/4, 12/6
- 3 speeds e.g. 8/4/2, 8/6/4

Voltage range:

Low-voltage up to 1000 V

Rated voltages:

All of the usual low voltages and voltage ranges according to IEC 60038. However, also: Non-standard voltages and / or frequencies according to customer specifications

Operating mode:

S1 and various

Degree of protection:

IP55, IP56, to IP68

Cooling type:

IC 411, IC 416, however, also special cooling types such as e.g. non-ventilated IC 410

Type of construction:

IM B3, IM B5, IM B35, IM V1, IM V3, IM V5, IM V18, IM B14, IM B34 (special) 


Gray cast iron


Ball bearings (standard) and special bearings for high axial (thrust) and radial forces



Types of protection:

Non sparking nA as well as dust explosion protection according to EN 50281-1-1 /
EN 50281-1-2

Noise level:

All motors are noise-optimized (noise limit values according to EN 60034-9), low-noise version possible for 2-pole motors (GG3)



  • Regreasing system from FS 160 - SPM nipple from FS 132 - stainless steel screws / bolts - larger connection system

  • Additional terminal box from FS 132 - anti-condensation heating from FS 132 - condensation water drain from FS 132

  • PTC thermistor as protection only (TMS) up to and including FS 250

  • PTC thermistor as additional protection (TMS)

  • Can also be supplied for 60 Hz (adapted winding - increased power rating)

  • All motors with insulating material class H

  • All motors are available with an electrical design according to "NEMA Standards Publication No MG1"

  • Flanged motors can be designed and implemented with flange and shaft end in accordance with NEMA

Special versions e.g. for:

  • Forced ventilation (for converter operation), mounted speed encoder, non-standard shaft end, backstop, special paint finishes

  • Low temperatures down to -60 °C

  • High-speed motors up to 12,000 rpm

Customer benefits

  • Special demands are realized
    => electric motor design adapted to special requirements

  • Larger connection system
    => adapted to the existing electrical system

  • Parameter-optimized motors
    => result in high efficiencies and high power factor with a low noise level

  • Temperature limits are maintained
    => extremely long lifetime

  • Quality components are used
    => Extremely high operational reliability

Typical applications

  • Pumps

  • Compressors

  • Fans

  • Extruders

  • Agitators

  • Branch Oil & Gas