Why did the motor of my Ryobi Belt Sander burn out?

Allow the motor to cool 

This issue may occur because the sander was used continuously for long periods without breaks to cool the motor. 

Why breaks are important 

All sanders need periodic rests during extended use to prevent overheating. 
If the motor overheats repeatedly, it could eventually burn out. 

Recommended practice 

As a guideline, after 30 minutes of continuous use, allow the sander to rest for 5–10 minutes before resuming.