Top Tips For Improving The Lifespan Of Servo Motors

Servo motors are powerful, compact solutions used across many process manufacturing applications. These lightweight motors produce significantly more torque than induction motors of similar physical size, making them ideal for applications with strict weight or space limitations, says Jonathan Bullick of KEB America.

The lifespan of a servo motor depends on multiple factors, from environmental conditions to application parameters. Most servo motor OEMs will list 20,000 to 30,000 working hours as a general range, but this will vary depending on how the machine is set up, maintained and operated.

Why do servo motors fail?

Like any machine, components of a servo motor will break down over time and frequent use. Any contact or friction between moving parts eventually leads to wear – and this process accelerates when the motor is incorrectly used and maintained. Common factors affecting servo motor lifespan include:

Bearing failure

Bearing failures are responsible for almost two-thirds of all motor failures. Repeated use of a servo motor causes its bearings to wear out and become misaligned, decreasing the motor’s overall lifespan. In particular, engineers will want to pay attention to the overhanging load ratings when designing a machine. Exceeding the published manufacturer ratings will accelerate bearing failure.

Overheating and contamination

Higher temperatures significantly affect motor life and performance. Poor ventilation, high environmental temperatures, as well as dirt or contamination will cause a servo motor to overheat, leading to thermal damage and failure. Almost all servo motors will be equipped with motor temperature sensors. These sensors should be used to detect abnormally high temperatures and respond accordingly to prevent motor failure.

Poor winding and cables

A servo motor’s windings and system feedback cables will degrade over time, resulting in performance issues and voltage spikes. Application factors such as long motor runs can exacerbate these issues.

Improper maintenance

Improper maintenance is a leading cause of servo motor failure and is therefore a key step that engineers should look at to improve motor lifespan. Most of the issues above can be can be controlled or prevented outright through intelligent maintenance. This includes basic activities such as maintaining correct belt tension.

How long do servo motors last?

Leading servo motor OEMs typically list the lifespan of servo motor bearings as 20,000 to 30,000 hours. However, depending on the application and operating conditions, servo motors can last for decades or less than a year. Why? Because some environmental factors and parameters are so harsh on the motor that it fails much earlier than expected.

Here are the key factors that affect servo motor life:

Motor speed

Speed determines how much input power is needed to sustain the servo motor. A servo motor running at high speeds will require more motor rotations, resulting in increased wear on the system’s bearings and other components. Motors operating at lower speeds generate less shock and vibration stress, which translates into a longer machine lifespan.

Motor duty cycles

Higher motor duty cycles result in increased oe even constant run time, shortening the total lifespan of the motor. Servo motors on continuous duty (S1) are expected to run steadily for huge stretches of time, exposing them to more stress and natural wear.

Environmental conditions

Factors such as uncontrolled moisture, oil, grease and high ambient temperatures adversely affect motor performance and operating life. Maintaining a clean, well-ventilated operating space is the best way to manage these threats.

How to improve servo motor lifespan

Choosing the right servo motor for the application

There are many types of servo motors, with some built for specific duty cycles and industrial applications. By understanding the demands of the application, engineers can invest in the right servo motor for those needs and constraints. A purpose-built motor will enable better performance across operations while improving the system’s lifespan.

For example, KEB AC synchronous servo motors can be configured with a range of feedback and brake options, as well as rotatable connectors for greater flexibility. These versatile DL3 servo motors are provided with low and medium inertia models for dynamic, efficient control – and are suitable for even the most demanding positioning and cycling applications.

Servo motor set up and upkeep

Once a servo motor has been selected, it is crucial to ensure the solution is correctly installed and well maintained. Improper installation causes problems that affect the system’s lifespan, from misaligned motor bearings to sub-optimal operating environments. This extends to selecting the correct feedback cables for the servo motor system. Without quality cabling, a high performance servo motor will run at a fraction of its potential and will hamper productivity.

Even a perfectly installed servo motor will need regular upkeep to maintain reliable output. This is where predictive maintenance can help; it empowers technicians to anticipate future motor problems and proactively fix them. Predictive maintenance reduces disruption, prevents costly downtime, and maximises the operating life of servo motors.    

For more information, please visit www.kebamerica.com