The IEC frame number is the key to a motor's mounting dimensions. In 132M, 132 is the height of the shaft centre above the foot base (mm); M indicates core length: S short, M medium, L long. For a given frame number, foot hole spacing, shaft height and shaft end dimensions are defined in the standard, so the frame number is the first information for assessing mounting compatibility. To confirm the fit, the mounting type, flange dimensions if any, as well as power, speed and electrical data must also be compared.

The HEM type code follows the same logic: 132M-4 means frame 132, length M and 4 poles. The same power may fall into different frames at different pole numbers:

  • 7.5 kW 2-pole: 132S
  • 7.5 kW 4-pole: 132M
  • 7.5 kW 6-pole: 160M

Shaft diameter, shaft length and key width are given by frame in the dimension table; in large frames the shaft of a 2-pole model may differ from other pole numbers. That is why the pole number must be known along with the frame number.

If there is no nameplate, measure the shaft diameter with calipers, the height from the foot base to the shaft centre with a rule, and the foot hole spacing; the height gives the frame number directly. Compare the values with the electric motor frame size table.