Identification of Motor Frame Size 132M & Motor EFF class EFF1 EFF2

EFF Class Motor Frame Size EFF class:

Motor Frame Size EFF class: It has mentioned at the left corner of the motor’s name plate. It means they says about efficiency class of the motor. The motor gives maximum efficiency is mentioned as EFF class. Types of efficiency class are

  1. EFF 3
  2. EFF 2
  3. EFF 1
  4. IE 1
  5. IE 2
  6. IE 3

EFF 3 class: maximum efficiency of 73 %

EFF 2 class: maximum efficiency of 80 %

EFF 1 class: Max. efficiency of 85 – 90 %

IE 1 class: Max. efficiency of 85 – 93 %

IE 2 class: max. efficiency of 90 – 95 %

IE 3 class motors:  maximum efficiency of 96 % above.

This is the standard eff class for Siemens make motors.

Simply say: the efficiency is of the motors will be    IE3 > IE 2 > IE 1 > EFF1 > EFF2 > EFF 3

Cost wise: EFF 3 < EFF 2 < EFF 1 < IE 1 < IE 2 < IE 3.

My recommendation: Always go for EFF1 type motor which gives better efficiency.

If you upgrade your motor from EFF1 to IE3, it will take 5 years to get payback with the condition of 365 X 24 hours running and 100 % load on the motor.


Some company’s marketer will ask you to upgrade your motor, but do not do it. During that payback time if motor failure that’s all, you cannot get pay back.

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Frame size of the Motor Frame Size EFF class:


This is very important mechanical data; it is very useful for motor alignment (to couple with load). It contains motor’s the core size and height from ground point to shaft center. Basically three type of motor core will come 1. S => shorter core, 2. M => medium core, 3. L => larger core.

Note: Core size does not matter for the alignment; we can modify the motor seating bed. But prefix number is most important, while purchasing a motor you must mention it.
Motor Frame Size EFF class


Ex1: Frame size is 132 S means…

S => Shorter core

132 = > distance between ground point to shaft center is 132 MM (Milli Meter)

Ex2: Frame size is 132 M

M => Medium core

132 => distance between the ground point to shaft center is 132 MM (Milli Meter)

Ex2: Frame size is 132 L

M => Larger core

132 => distance between ground point to shaft center is 132 MM (Milli Meter)

Also see:

Thanking You !!! Have a Nice Day….

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