Low voltage motors for maximum safety and security as well as availability in the oil and gas industry

General description

LOHER VARIO PLUS series have a modular cooling design featuring double-flow inner cooling for a high power density and a homogeneous temperature distribution.2 versions are available:

Mounted air-water heat exchanger (JNWK–... type for roller bearings / JNXK-... for sleeve bearings):
Optimum cooling is guaranteed specifically for these series due to the harmonized and coordinated heat exchanger. The motor power loss is dissipated through the cooling water and is therefore de-coupled from the ambient temperature. The heat exchangers are available in a wide variety of versions with single and double pipe types. The high quality heat exchanger materials used are adapted to the specific requirements.
Mounted air-air heat exchanger (type JNRK–... for roller bearings / JNQK-... for sleeve bearings):
The motors are equipped with air-air heat exchangers. The cooling pipes are manufactured out of galvanized steel; stainless steel versions are available for especially aggressive atmospheres.


Technical data overview

Brief overview



Shaft heights:

500, 560, 710

Power range:

200 kW - 5600 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

Frequency converter:

Line and converter operation

Degree of protection:

IP23, IP55, IP56

Cooling type:

IC611, IC616, IC666, IC81W, IC86W, IC01

Type of construction:

IM B3, IM B35, IM V1, IM V10


Welded steel


Roller bearings, sleeve bearings



Explosion protection:

II3G Ex nA II T3

Type of protection:
without explosion protection


Noise level:

max. 85 dB(A) (Load, 50 Hz), lower noise versions are available


  • Also available for exceptional requirements - such as dust explosion protection.

  • 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.

  • 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.

  • All motors have a double flow inner cooling for a high power density and a homogeneous temperature distribution.

Customer benefits

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

  • 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 2 for

  • Pumps

  • Compressors

  • Fans

  • Centrifuges

  • Branch Oil & Gas