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Entry type: FAQ Entry ID: 30320280, Entry date: 08/12/2008

What is an IM code, and what types of electrical machines are there?

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What is an IM code, and what types of electrical machines are there?







Type of construction and installation are identified with an inter-nationally standardized IM code in accordance with IEC 600 34-7.




This code takes into account:

  • The position of the motor shaft

  • The type of bearing shield

  • Fastening of the machine

  • Method of installation

  • Nature of the shaft end




The following characteristics are not recorded in the IM code and have to be agreed on:

  • Position of terminal box

  • Type of bearing

  • Shape of the shaft end

  • Position of the ventilation holes

  • Type of torque transmission, among other things




Code I:

Suitable for machines with bearing shields and one shaft end
           Code example: IM B3






Code II:

Suitable for all machines            Code example: IM 1001








Code I is preferred for describing the types of construction.

Code II is used in cases in which Code I is not sufficient for complete description of the type of construction.



Types of construction of motors are defined in the standard

IEC 600 34-7.

The most common types of construction at SIEMENS are:


(Statement of IEC 600 34-7)


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