How to Solve Servo Alarm 15
  • 28 Dec 2020
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How to Solve Servo Alarm 15

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Article Summary

Zhafir Service Department Training Files
Servo alarm NO.15


As the voltage of DC bus is more than 500 volts, and the inverter capacitor discharge also take some time. So please be very careful while doing inverter-related operation.

Alarm principle:

This alarm is the start resistor failure, when inverter starts, the supply will charge the capacitor, and will have a large current. So it will need a start resistor working here to reduce the start current. The E.LSF (NO.15) alarm will occur while the start resistor fails. 


  1. DC fuse burned.
  2. KEB inverter failure.


  1. Check the DC fuse to see if it is burned. If the DC fuses have been burned, the controller will give out the historical alarm saved in KEB parameter IN24, in other word, this alarm is an illusion. In this case, there are two ways to inspect.
  2. First, measure the resistance of the corresponding fuses, (the two connected with wires numbered 21,21 is fuses for charge unit, and 31, 32 is for mold unit, 41,42 is for ejector unit.) 

If the fuses burned, replace the fuses after confirm there are no other short circuit.

Second, login the 5 level, go to the KEB parameter page, turn on the motor and observe the value of “Ru00”, if it is “15”, then it is real alarm NO.15. If it is “2” or “13”, then it is the fuse problem, the alarm is just an illusion. Replace the fuses after confirm there are no other short circuit.

2. If the fuses are OK, and restart the machine, turn on the motor, it is still got “servo system alarm NO.15”, then it is the KEB failure, need to replace the KEB.

If it needs to replace the inverter, please see the instruction “How to replace an inverter.”

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