EM Brno s.r.o.

Jílkova 124
615 35 Brno
Czech Republic

GPS: 49°11'50.52"N, 16°38'8.74"E

DC Traction motors series 3M

Basic Information


Drive motors of 3M series are designed for drives of small road and railway vehicles, fork lift and platform trucks and further for auxiliary drives of servomechanisms, hydro mechanisms, fans, air compressors, etc.


Motors are manufactured of axial heights:


56 mm 63 mm 71 mm 80 mm
100 mm 112 mm 132 mm 160 mm


The frame consists of a steel tube providing sufficient mechanical rigidity with welded feet. In the case of bigger and highly loaded machines the flange or even commutator shield are made of refined cast iron, in other cases from cast iron. Motor machine design allows to supply traffic of the motors with different nominal speed preserving chosen driving voltage.


Motors can be powered from converters, connected to accumulator batteries or to direct-current mains at voltage from 12 to 120 V, according to size of the motor.


Rotors are dynamically balanced with half-key. Free shaft end is cylindrical with key, on demand it can also be smooth tapered, with screw, differently shaped, optionally even with gear or with serration. The second shaft end is also possible.


Ball bearings are with permanent fat filling, on demand the bearings can be also with an increased radial clearance C3 or with lubrication with a higher temperature resistance (for operating temperature of the bearings 80°C and higher).


Technical Information


Motors can be provided with different excitation windings, dependent on the way of use:


series excitation (S)         suitable for traction use, high starting torque, speed decreases with increasing load
separate excitation (C)          powering from independent unit, which simulatex series excitation
parallel excitation (D) usually only for one sense of rotation (pumps, compressors), not suitable for drives - to stron source loading
compound excitation (K) series and parallel excitation, very suitable - it limits the speed druing the no-load motion, all kinds of machines

For reversation of rotation speed each motor has to be equipped with two separate terminals for armature (rotor) and two to four for excitation (stator).

Motor protection:


IP 2 (opened)  with different protection level against dripping or sprinkling water (part of the protection forms fastening in the vehicle)
IP 44 (closed)

increases seriously the mass of the motor and reduces achievable power of the motor to 30 - 40%           




IC 01 usually accomplished by fan, attached to the shaft
IC 00 without cooling

Common working environment, ambient temperature from -20 to +40 °C. On demand it is possible to provide increased resistance against humidity, corroding process, dust, better surface painting.


Insulating materials are in the class  of thermal resistance F, conductors and slot insulations in the higher class F/H or H. At the extremely loaded machines there are used conductors with double insulation layer (overcoat). 

Feet shape IM 2… is being used at the biggest machines of size H132 and H160. Attachment of the motor on feet or flanges, in case of attachment both on feet and flanges both mounting areas have to be perpendicular to each other. Direction of rotation is always to the right (clockwise) assuming the view on the free shaft end, while (+) polarity of the source is to be connected to all terminals with index 1 (beginning). 

Terminal markings:


  A armature, rotor                  
  B auxiliary poles
  C compensation
  D serial excitation
  E parallel excitation
  F separate excitation

Time of motor operation of 3M series is very various, nominal values are evaluated for load of 60 minutes (short-term operation S2 – 60 min). At interrupted load S3 there is usually given acceptable duty factor (time of operation at full load is related to the cycle time, most often T = 10 minutes). For drives of hydraulic pumps for example.
S3 – 15% (1,5 minute motor operation, 8,5 minute standstill).


Approximate values of load: 


Duty cycle       S1    S3-60% S3-50% S3-40% S3-25% S3-15%


     1,0   1,3 1,4 1,6 2,0 2,5


Repeated motor overload above 1,6In at time over 30s is to be discussed with the manufacturer.

Detailed information can be found under the Documents tab to download.

Look at other motors from our production program.

20.11.2017  SPS/IPC/DRIVES 2017
 Dear customer, we invite you to visit us on  Electric Automation - Systems and Components Trade Fair   SPS/IPC/DRIVES 2017 from 28. to 30. November 2017 in Nuremberg.   You will be welcome in our exposition, hall 3, stand 660.  
04.09.2017  IEF Brno 2017
  International Engineering Fair in Brno 9. - 13.10. 2017   We invite you to visit our exhibition at the International Engineering Fair in Brno in the hall Z, stand 131.        We are looking forward to meet you.   I-catalogue of exhibitors and products Map of Exhibition Centre