What happens to the output speed if I fit a 1,000 rpm electric motor to the same gearbox?

The gearbox ratio is fixed; output speed = motor speed / ratio. As the number of poles rises the motor speed falls, so the output speed falls by the same proportion.

Points to watch:

• Torque: at the same power a 6-pole motor delivers more shaft torque (here about 22 Nm instead of 14.5 Nm). At the gearbox output the torque rises by the same proportion; check that the frame can carry it.
• Flange: as the example shows, a 6-pole motor of the same power can be one IEC frame larger; the gearbox input may not fit this flange.
• Flexibility: changing poles is a one-step change in speed; if continuous adjustment is needed, other methods are considered.

The example values are taken from the model data; the final selection is made according to the machine load and the gearbox catalogue.