A readable nameplate photo is often enough; but if the nameplate is worn, painted over or lost, the equivalent is found from the motor's dimensions and the machine's operating data.

To measure on the motor

  • Shaft height: from the foot base to the shaft centre (mm); gives the IEC frame number.
  • Shaft diameter and length, key width
  • Foot hole spacing: across and along
  • Flange, if any: outer diameter, spigot diameter, hole pitch, whether the holes are tapped or clearance
  • Motor length and terminal box position

To collect from the machine

  • Machine type and operating speed; with a belt drive, both pulley diameters
  • Current measured while running and the supply voltage
  • Whether it starts loaded, daily operating time, starting method
  • Environment: dust, humidity, temperature, enclosed space

If power is unknown, the measured current is assessed together with the nameplate currents of models in the same frame. Current alone does not give power exactly, because it is not known whether the motor was at full load when measured. You can send the data via the send motor nameplate and find an equivalent page; our shaft and foot dimension check article helps with measuring.