The LOHER "Ex e Motor" - increased safety for use in hazardous Zone 1

General description

LOHER Motors with type of protection "e" (increase safety) distinguish themselves as the various components are optimally harmonized with one another (winding / rotor and components).
This is the reason that special construction regulations also apply for these motors.
When compared to motors with a flameproof enclosure, which makes any ignition non-hazardous, the protection philosophy for these motors is to avoid ignition, even when a fault situation occurs.
The permissible winding temperatures are reduced, which in turn results in a longer lifetime and a low risk of ignition.
Fault situation "locked rotor": LOHER Ex e motors set themselves apart as a result of the higher (than specified) safe locked rotor time - tE - this makes drive monitoring simpler, safer and uncritical.
"Increased safety" therefore also involves a longer service life and especially a higher degree of reliability and operational safety.


Technical data overview

Brief overview



Shaft heights:

Frame sizes 090 - 355 mm (area of standard motors)

Power range:
(50 Hz types)

Up to 220 kW (thermally utilized to temperature class B at TU = 40 °C)

Number of poles:

2 - 8 pole; also higher pole numbers for special versions

Pole changing
2 speeds, e.g. 4/2, 6/4, 8/4, 8/6

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:


Degree of protection:

IP55, IP56, to IP66

Cooling type:

IC 411

Type of construction:

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


Gray cast iron


Ball bearings



Types of protection:

"e" 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 or Pt100 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:

  • Special shaft end, backstop, special paint finishes

  • Low temperatures down to -60 °C

  • Available in temperature class T4 and also for increased ambient temperatures

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

  • In comparison to the standard and other Ex motors: Lower winding temperature limits
    => an even longer service life

  • Quality components are used
    => Extremely high operational reliability

Typical applications

  • Pumps

  • Compressors

  • Fans

  • Extruders

  • Motors in process systems

  • Branch Oil & Gas