A poorly selected or improperly applied bearing can:
- cause noise
- generate vibration
- lead to overheating
- ultimately result in motor failure
And most importantly: in many cases, this could be prevented.
The role of the bearing in an electric motor
The bearing is one of the key components in the operation of an electric motor.
- ensures stable shaft rotation,
- reduces friction,
- carries loads,
- dampens vibrations.
If a failure occurs here, it affects the performance of the entire motor.
Electric motor bearing selection – this is where service life is determined
In practice, selection is often based solely on size.
However, in reality, it is a much more complex decision.
- rotational speed,
- load,
- operating time,
- environmental conditions,
- lubrication options.
The result of improper selection is almost always the same:
- overheating,
- noise,
- vibration,
- premature failure.
Noise, vibration, overheating – they occur together
These three phenomena are almost always interconnected. As friction increases, running accuracy decreases, and lubrication becomes unstable.
As a result:
- noisier operation,
- the appearance of vibration,
- rising temperature.
This does not happen suddenly. It is a gradual deterioration process.
C3 clearance – when is it required?
In most electric motors, C3 clearance is considered an industry standard.
During operation, the bearing heats up and the shaft expands. If there is not enough internal clearance, the bearing becomes overloaded.
- compensates for thermal expansion,
- reduces the risk of seizure,
- ensures more stable operation.
2RS or ZZ bearing – the environment decides
The type of sealing often matters more than the bearing type itself.
2RS version
- better protection against dust and moisture,
- a more sealed system,
- safer in contaminated environments.
ZZ version
- lower rolling resistance,
- suitable for higher speeds,
- ideal for clean environments.
The choice always depends on the operating environment.
Lubrication – the most common source of failure
A significant portion of bearing failures can be traced back to lubrication issues.
- insufficient lubrication → wear,
- over-lubrication → overheating.
In the case of over-lubrication, the bearing churns the grease, which accelerates degradation.
Electrical effects – when this also becomes a factor
In variable frequency drive (VFD) applications, bearing currents may occur. These can cause micro-damage on the raceway surfaces. In such cases, the use of insulated bearings may be necessary.
The operating principle is simple: the bearing interrupts the electrical current path, preventing discharge through the rolling elements.
NTN Megaohm bearings are manufactured with a special electrically insulating coating, which interrupts the current flow through the bearing.
- reduces electrical damage,
- extends service life,
- ensures more stable operation.
Installation – where many things are decided
Many failures originate during installation.
- impact-based (hammer) mounting,
- improper fit,
- damage to the shaft or housing.
These issues typically appear later as noise or overheating.
Solution: proper bearing installation
Simatool bearing installation kits are specifically designed for fast and safe bearing mounting.
Key advantages:
- impact-free installation,
- precise fitting,
- quick and easy handling,
- reduced installation risk,
- fewer subsequent failures.
Especially recommended for maintenance teams and service technicians, where speed and reliability are critical.
The bearing is not a minor component. It is one of the most critical elements in an electric motor. Selection, lubrication, and installation together determine service life and operational reliability.
If you need help with selection, installation, or finding the right solution,
feel free to contact us.
