If the shaft and flange fit, the motor can be physically installed, but that does not mean it will work correctly on the machine. Go through this list before replacing:

  • Speed and poles: a motor with a different pole number may fit the same flange; the pump or fan speed changes.
  • Power and torque: one frame can carry more than one power; compare with the old nameplate.
  • Voltage and connection: the nameplate voltage must suit the supply and the starting arrangement in the panel.
  • Mounting position: if the motor will be used vertically (V1, V5 etc.), state this when ordering.
  • Motor length and fan clearance: there must be space behind the fan cover for air to enter.
  • Terminal box position and cable entry: box orientation, cable reach and gland size.
  • Direction of rotation: check it at first start on single-direction fans and pumps.
  • Environment: ambient above +40 °C, altitude above 1000 m, enclosed cabinet, dust and humidity.
  • Accessories: if the old motor had a PTC/PT100 sensor or anti-condensation heater, request it on the new one too.

An example comparing old and new motors on a base is in our 55 kW motor replacement base fit article; flanged models are on the B5/B14 flange motors page.