Why Selecting a Gearbox Based Only on Power Often Leads to Early Failure
In gearbox selection, power is usually the first parameter provided.
Many discussions start with power, and in some cases, the entire selection process revolves around it.
In real applications, however, choosing a gearbox based only on power is one of the most common reasons for early failure.
The reason is simple.
Power describes theoretical output capability, but it says very little about how the gearbox is actually stressed in real operating conditions.
In many projects, failures do not occur because the rated power is insufficient.
They occur because operating factors that power alone cannot reflect are overlooked.
For example, under the same power rating:
continuous operation and frequent start–stop cycles place very different stresses on internal components;
stable loads and fluctuating or impact loads affect bearings and gear sets in completely different ways.
When selection focuses only on power, these differences are often ignored.
As a result, issues tend to appear first as abnormal noise, unexpected temperature rise, or premature wear.
This is also why, in some applications,
a gearbox may appear “safely oversized” based on power calculations,
yet still experience reliability problems much earlier than expected.
Power is a necessary parameter,
but it should be used as a validation result rather than the starting point of selection.
If operating conditions such as duty cycle, load variation, and start frequency are not considered during the selection stage,
any gearbox chosen purely on power margins carries an inherent structural risk.
