Why is the VOC test failing when the output voltage is within test limits?
The VOC test includes a phase test and a voltage test.
If either the voltage or phase test fails this will result in an overall fail.
For example, If the voltage test passes and the phase fails this will result in an overall fail. Therefore, a transformer may pass all voltage tests but still fail if the phase test fails or the phase test has not been set correctly when the program was written. Sometimes users are not concerned about phase, only voltage.