In most cases they do not. In the HEM Motor catalogue, the IE3, IE4 and IE5 families sit within the same IEC frame system; shaft height, foot holes and flange size are standard for a given frame number.

Still, some points need checking:

  • Frame length: higher efficiency may need a longer core; the space behind the motor and the clearance at the fan cover matter.
  • Bearings: the catalogue bearing table lists the bearing choice separately for 2-pole IE4 models from frame 160 upwards.
  • Speed: slip may be smaller in the higher class, so the motor runs slightly faster. On pumps and fans this slightly increases flow and absorbed power.
  • Starting values: the starting current ratio can vary by model; review protection settings against the new nameplate.

For a motor going onto an existing base, the old motor's frame number (e.g. 132M) and mounting arrangement are the first information; to confirm the fit, shaft diameter and length, foot hole spacing, flange dimensions if any, as well as power, speed and electrical data must also be compared. Send photos of the current motor's nameplate and connections on WhatsApp and we will confirm the right model. Check the dimensions for your chosen model in the technical catalogue and drawings section.