Chapter 5 Methods of Anomaly Diagnosis |V FD-VJ- 
 
 
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5-3 Resolution for electromagnetic noise and induction noise 
 
If there exist noise sources around hybrid servo drive, they will affect hybrid servo drive through 
radiation or the power lines, leading to malfunction of control loop and causing tripping or even 
damage of hybrid servo drive. One natural solution is to make hybrid servo drive more immune to 
noise. However, it is not economical and the improvement is limited. It is best to resort to methods that 
achieve improvements outside hybrid servo drive. 
1.  Add surge killer on the relay or contact to suppress switching surge between ON/OFF. 
2.  Shorten the wiring length of the control circuit or serial circuit and separate from the main 
circuit wiring. 
3.  Comply with the wiring regulation for those shielded wire and use isolation amplifier for long 
wire. 
4.  The ground terminal of hybrid servo drive must be connected to ground by following the 
associated regulations. It must have its own ground connection and cannot share with 
electrical welder and other power equipment.   
5.  Insert noise filter to the input terminal of hybrid servo drive to prevent the noise entering 
from the power lines. 
In a word, three-level solutions for electromagnetic noise are “no product”, “no spread” and “no 
receive”.