I have a prepelxing voltage anomaly:
I have a 3 phase 120/208V panel fed by a 20KW UPS loaded at 75%
A=27A
B=35A
C= 25A
amperage is seen during the day when most loads are running.
Voltage at panel is between 118V and 120V normally on each phase to nuetral
I attached a voltage monitor [did not measure currrent] to the load side of the UPS [at feed to panel served by UPS] for 5 days- during this time period I only recorded a single 13 minute voltage anomaly where:
A phase went to 128.8V
B phase went to 102.9V
C phase went to 128.5 volts
All simultaneously.
After 9 minutes B phase went back to normal range C phase sagged at 104V for 3 minutes and A phase still surged for 3 more minutes
All known loads connected are lab type equipment, no 3 phase loads...some 208V loads [double tub panel approx. 80 circuits being used]
Any body want to guess what may be happening here??????????
I have a 3 phase 120/208V panel fed by a 20KW UPS loaded at 75%
A=27A
B=35A
C= 25A
amperage is seen during the day when most loads are running.
Voltage at panel is between 118V and 120V normally on each phase to nuetral
I attached a voltage monitor [did not measure currrent] to the load side of the UPS [at feed to panel served by UPS] for 5 days- during this time period I only recorded a single 13 minute voltage anomaly where:
A phase went to 128.8V
B phase went to 102.9V
C phase went to 128.5 volts
All simultaneously.
After 9 minutes B phase went back to normal range C phase sagged at 104V for 3 minutes and A phase still surged for 3 more minutes
All known loads connected are lab type equipment, no 3 phase loads...some 208V loads [double tub panel approx. 80 circuits being used]
Any body want to guess what may be happening here??????????