1.1 Scope
This standard specifies the IM Code, a classification of types of construction, mounting arrangements and the terminal box position of rotating electrical machines.
Two systems of classification are provided as follows:
Code 1 (see Chapter 2): An alpha-numeric designation applicable to machines with end-shield bearing(s) and only one shaft extension.
Code 2 (see Chapter 3): An all-numeric designation applicable to a wider range of types of machines including types covered by Code 1.
The type of machine not covered by Code 2 should be fully described in words.
The relationship between Code 1 and Code 2 is given in annex A (Informative).
1.2 Definitions
For the purposes of this standard, the following definitions apply:
1.2.1
Type of construction
The arrangement of machine components with regard to fixings, bearing arrangement and shaft extension (see GB/T 2900.25).
1.2.2
Mounting arrangement
The orientation on site of the machine as the whole with regard to shaft alignment and position of fixings (see GB/T 2900.25).
1.2.3
Shaft extension
A portion of a shaft extending beyond an extreme bearing (see GB/T 2900.25).
NOTE: The bearing may be on the machine itself or be part of an assembly comprising a machine and (an) additional bearing(s).
1.2.4
Drive-end of a machine (D-end)
That end of the machine which accommodates the shaft end (see GB/T 2900.25).
NOTE: This is normally the driving end of a motor or the driven end of a generator.
Where for some machines the above definition is inadequate, the D-end is defined as follows:
a) Machine with two shaft extensions of different diameter: the end with the larger shaft diameter;
b) Machine with a cylindrical shaft extension and a conical shaft extension of the same diameter: the end with cylindrical shaft extension;
c) Machine with other arrangements: according to GB 1971 if applicable; otherwise by agreement.
NOTE: The outer diameter of a forged-on flange is taken to be the diameter of the shaft extension.
1.2.5
Non-drive end of the machine (N-end)
That end of the machine opposite to the drive end (see GB/T 2900.25).
Foreword I
1 Scope and Definitions
1.1 Scope
1.2 Definitions
2 Code 1 (Alpha-numeric Designation)
2.1 Designation of machines with horizontal shafts
2.2 Designation of machines with vertical shafts
2.3 Terminal box location
3 Code 2 (All-numeric Designation)
3.1 Designation
3.2 Significance of the first numeral
3.3 Significance of the fourth numeral
3.4 Significance of the second and third numerals
3.5 Terminal box location
3.6 Examples of designations
Annex A (Informative) Relationship between Code 1 and Code 2
