The idea that "a bigger motor does no harm, it only draws what the load needs" holds in normal running; the risk lies in abnormal moments. An induction motor's starting and breakdown torque can rise well above its rated torque. When the machine jams or the load gives a sudden shock, this torque reaches the gearbox output multiplied by the ratio.

Possible consequences:

  • wear, pitting or breakage of gear teeth,
  • damage to the output shaft or key,
  • early bearing failure,
  • the flange not fitting the gearbox input because the motor frame is larger.

If more power is genuinely needed, the right path is to move up one gearbox frame. If the existing motor is not enough, first find the cause: wrong ratio, overload or high losses. On machines at risk of jamming, mechanical protection such as a torque-limiting coupling can also be considered.