Low voltage motors for maximum safety and degree of availability in the oil and gas industry

General description

The LOHER VARIO Ex d(e) series has a welded steel enclosure for the highest degree of variability and versatility. Flange rings at the ends of the enclosure increase the torsional stiffness and ensure a vibration-proof mechanical design. The steel version allows various bearing concepts, dimensions can be adapted and a wide range of instruments can be mounted.
The surface cooling using flat ribs combined with a defined inner cooling circuit with shaft-mounted fan inside the motor ensure optimum motor utilization. The copper bar rotors used as standard allow starting and operating parameters to be optimized for each and every application.
With power ratings up to 2800 kW, these motors are mainly used for conveying, transporting and compressing. The rugged version allows safe, reliable and straightforward operation in Zone 1 both for line and converter operation.


Technical data overview

Brief overview


DN.. / MLFB: 1PS4, 1PS5

Shaft heights:

355, 400, 450, 500, 560, 630

Power range:

90 kW - 2800 kW

Number of poles:

2 - 16 poles, higher pole numbers on request

Voltage range:

380 V - 950 V

Rated voltage:

380 V / 400 V / 415 V / 500 V / 660 V / 690 V

Degree of protection:

IP55, IP56, IP65, IP67, IP68

Cooling type:

IC 411, IC 416

Type of construction:

IM B3, IM B35, IM V1


Welded steel


Roller bearings, sleeve bearings (only for gas group IIB)



Explosion protection:

II2G Ex d(e) IIB T4, II2G Ex d(e) IIC T4

Type of protection:
without explosion protection


Noise level:

max. 86 dB(A) (Load, 50 Hz), lower noise versions are available


  • Also available for exceptional requirements such as dust explosion protection or double protection Ex e and Ex d.

  • Corrosion protection using special paint finishes according to the manufacturer's standard or customer's specification.

  • The motors are available as special version for polar regions down to -40 °C (without pre-heating of the motor) or desert regions up to +60 °C.

  • When required, vertical motors can also be equipped with thrust bearings for high axial and radial loads.

  • Operation with frequency converters is possible without any complex system test.

  • Wide range of connection systems for large cable cross-sections, high short-circuit strength or phase-segregated version.

  • Optimized starting and operating parameters and high efficiency by using copper bar rotors as standard.

Customer benefits

  • Complies with almost all of the user requirements and specifications (no deviation philosophy)

  • Engineered based on international standards (ATEX, NEPSI, GOST-R, CCOE certified)

  • High level of acceptance in the various sectors. For instance, Shell and DOW recommend these motors

  • Complete project documentation guarantees minimum planning costs

  • High degree of cost effectiveness and low operating costs as a result of the optimum electrical and mechanical values

  • High degree of variability and versatility using a welded steel enclosure (to adapt the dimensions, mounted components)

Typical applications

Used in Ex-Zone 1 and 2 for

  • Pumps

  • Compressors

  • Fans

  • Centrifuges

  • Branch Oil & Gas