How to understand designations on asynchronous electric motors?

Specification is given on the factory guard which fastens to the electric motor body. On it the key parameters which are rather fully characterizing the electric motor are written down: rated power on the shaft (kW), rated voltage (V) with the indication of the corresponding scheme of connection of windings, current intensity (A) for each scheme of connection, the rated frequency of rotation (RPM), current frequency in network (Hz), electrical power factor - cosf, efficiency - the efficiency (%), the isolation class, type of the electric motor and its weight (kg).

Обозначения на асинхронных электродвигателях

Designations on asynchronous electric motors.

Main designs of asynchronous electric motors

The variety of the performed works and conditions in which asynchronous electric motors are operated caused that the industry releases them in different design. On security degree electric motors release:

  1. Opened - without special devices for protection from accidental touch to the rotating and current carrying parts and also for prevention of hit in foreign objects, etc. (have limited distribution).
  2. Protected - the having devices for protection from accidental touch to the rotating and current carrying parts and also for prevention of hit in foreign objects.
  3. Drip-proof - supplied with devices for protection of internal parts from hit of the drops of moisture falling aweigh.
  4. Closed - at them the internal cavity is separated from the external environment by the cover interfering dust penetration.
  5. Explosion-proof - i.e. protected so well that they are allowed to application in explosive rooms.

On the mounting mode distinguish the flange, vertical, built-in electric motors, etc.

Designation of electric motors of different design

Depending on the mounting mode or installation of the electric motor by the machine, apply the following designations:

Структура условного обозначения электродвигателя

Structure of the legend of the electric motor.

  1. M101 - the engine installed horizontally and fixed on paws which are welded on the bed or are cast together with it.
  2. M201 - the engine of horizontal installation suspended on paws which are located above on the bed.
  3. M301 - the flange engine intended for horizontal installation; on the bearing board (from the end of the shaft) has the ring flange with openings for bolts and the centering sharpening.
  4. M302 - the engine of vertical installation (the working end of the shaft down); is fixed by means of the flange on the bearing board from the working end of the shaft (the engine leans on the flange).
  5. M303 - the same, as M302, but for installation by the working end of the shaft up; is fixed by means of the flange on the bearing board from the working end of the shaft (the engine is suspended on the flange).
  6. M102 - the same, as M302, but with fixing only on paws.
  7. M103 - the same, as M102, but is established by the working end of the shaft up.
  8. M202 - the same, as M302, but with fixing by means of the flange on the board and paws on the bed.
  9. M203 - the same, as M202, but with installation of the working end of the shaft up.

Types of electric motors

 Along with use of electric motors of the series 4A, also earlier being issued electric motors of the uniform series A, JSC, A2 and AO2 find application.

In rooms with the increased humidity or with hostile environment use electric motors of the special purpose.

  1.  Series 4A electric motors - the asynchronous three-phase electric motors released instead of electric motors of the uniform A2 and AO2 series. They, in comparison with electric motors seriia2 and AO2, have smaller weight (on average for 18%), dimensions, noise level and vibrations, the big starting moments and the increased operational reliability.
  2. Interpretation of alphabetic and digital references of electric motors of the series.

The letters and digits entering designation of the electric motor are deciphered as follows:

  1. 4 - series.
  2. And - designates that the engine asynchronous.
  3. The second letter behind the letter A designates execution of the electric motor on the way of protection against the environment.
  4. The third letter specifies execution of the engine on material of the bed and boards (And - the Bed and boards aluminum;  Х - the bed aluminum, boards - pig-iron; the lack of the letter means that the bed and boards pig-iron or steel).
  5. Three or two subsequent digits specify spin axis height in millimeters from 50 to 355.
  6. The following letters designate installation dimensions longwise of the bed (S - short, M - average, L - long).
  7. In engines with identical lengths of the bed, but with different lengths of cores of the stator additional designations of cores are applied: And - short, In - long.
  8. The subsequent digits (2, 4, 6, 8, 10, 12) mean number of poles.
  9. Final letters and digits indicate climatic modification and category of placement.

So, for example, designation 4AA50A2U3 is deciphered so: the electric motor is asynchronous, the fourth series, the closed execution which bed and boards are made of aluminum, height of the spin axis of 50 mm, the core short, number of poles 2, climatic modification At, category of placement 3.

Electric motors asynchronous ACORUS series

The ACORUS electric motor - the unified series of asynchronous electric motors. The ACORUS series covers the power range from 0,06 to 315 kW characterized by values of height of the spin axis from 50 to 355 mm and rotating speeds 3000, 1500, 1000, 750 RPM.

Electric motors of the AIR asynchronous three-phase alternating-current series are intended for the complete set of electric drives of different mechanisms in all industries and the agrarian complex. Frequency of 50 and 60 Hz, voltage is 220-660 V (the ACORUS of 71 - 220-440 V). Degree of protection of IP54 electric motors (by request of IP55), degree of protection of IP55, the class of isolation of F.

Structure of the legend of electric motors


  1. Vladimir

    What standard, TU … regulates Execution of the engine on material of the bed and boards

    To answer
  2. Ivera

    Engine 4A18034UZ. It is clear all but one tsiferka 3, after 180

    To answer
  3. Pyotr

    decipher the engine tm-41/4-2

    To answer
  4. Danil


    To answer
  5. Alexander

    Decipher please engines of the joint-stock company 944 and DB31

    To answer
  6. Oleg

    decipher the engine 4ai355u3

    To answer
  7. Oleg

    And the DAMSh engine — the engine asynchronous **** *****. HZ is shorter.

    To answer
  8. Evgeny

    Well also decipher the most unclear HAVING GIVEN the DAV-315-4U3 engine to me?

    To answer
    • Max

      YES — the engine asynchronous, In has to designate protection; can, moisture-proof. You know the rest — the spin axis height, number of poles, the temperate climate and category of placement in buildings.

      To answer
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