AP7721, Fault exists on Source A where is connected Smart-UPS SC 450VA

[Anonymous user]

Hi,

I have an AP7721 for which both input powers sources comes from 2 UPS's, one is Smart-UPS SC 450VA (Source A) the other one is a very old Blazer 2000 (Source B). Default is Source A

In case of power outage the AP7721 switch over on Source B and display an alarm that switchover not possible anymore because "Fault exists on Source A"

The configuration of AP7721 is a follow:

• Frequency Deviation: 3
• Voltage Transfer Range: wide
• Sensitivity: low
• Line VRMS: 230
• Wide VRMS Limit: 35

By looking on Source Measurements the values for

• Source A (the one with the fault) are:
  • Input Frequency: 60 Hz 
  • Input Voltage: 243 VAC
• Source B  are:
  • Input Frequency: 50 Hz
  • Input Voltage: 223 VAC

Both devices AP7721 and Smart-UPS SC 450VA are brand new (2 month).

This scenario is reproducible in case of power outage.

Regards,

Ciprian