Voltage Window | Frequency Window | Reference Standard |
0.9 to 1.1 UN | 0.99 to 1.01 fN | IEEE P1547 |
0.8 to 1.15 UN | 0.94 to 1.02 fN | VDE 0126, OVE E2750 (partly) |
0.8 to 1.2 UN | 0.994 to 1.006 fN | DK 5950 |