Ratings for Vacuum Electric Switches
| Design Voltage Nominal/Maximum (kV) | 15/15.5 | 34.5/38 | 46/48.5 | 69/72.5 | ||
| Continuous current (RMS Amperes) | 6005 | 6005 | 300 | 6004, 5 | 300 | 300 |
| Fault Interrupting Current (RMS Amperes) Max. | 4000 | 4000 | 3000 | 4000 | 3000 | 3000 |
| Momentary Current (RMS Amperes, Asymmetric) | 20,000 | 20,000 | 15,000 | 20,000 | 15,000 | 15,000 |
| Frequency (Hz)³ | 50/60 | 50/60 | 50/60 | 50/60 | 50/60 | 50/60 |
| Two-Second Current (RMS Amperes) | 12,500 | 12,500 | 12,500 | 12,500 | 12,500 | 12,500 |
| Four-Second Current (RMS Amperes) | 9000 | 9000 | 9000 | 9000 | 9000 | 9000 |
| Impulse Withstand, Terminal-to-Terminal (kV) Line-to-Ground (1.2 X 50 Positive Wave) | 1101/150 | 2001/200 | 2001/200 | 2001/250 | 2501 | 2801/350 |
|
Maximum 60-Cycle Withstand Line-to-Ground (kV) One Minute Dry Ten Seconds Wet |
101 74 |
138 119 |
138 119 |
178 176 |
178 176 |
245 198 |
| Maximum Peak In-rush Current (RMS Amperes) | 20,0002 | 20,0002 | 15,0002 | 20,0002 | 15,0002 | 15,0002 |
1The terminal-to-terminal BIL is not established by a visible open gap and therefore cannot be used to establish safety clearance for personnel.
2 When switches are used for capacitor bank switching, restrike probabilities are determined by the magnitude of the in-rush current, the contact open gap, and the contact material. This is explained in a Toshiba paper found in IEEE Transactions on Power Delivery, Vol 10, No. 2 April 1995. Using reactors to reduce in-rush current reduces restrike probability. In back-to-back capacitor switching peak currents should be limited by reactors to a switch’s fault interrupting rating. The contact material used in these switches is copper tungsten the same as reported to have the lowest restrike probability in this Toshiba paper. In aged switches with high operation counts, contact welding may occur if the in-rush currents are not limited.
3Switching a harmonic filter requires special considerations. Consult the factory about these applications.
4For capacitor bank switching only, this switch is limited to being used on solidly grounded systems and solidly grounded capacitor banks with currents of less than 200 amperes.
5When switches are used in parallel, the continuous current rating is reduced to 500 amperes to account for unequal current distribution between switches.
6When switches are used for capacitor bank switching, restrike probabilities are determined by the magnitude of the in-rush current, the contact open gap, and the contact material. This is explained in a Toshiba paper found in IEEE Transactions on Power Delivery, Vol 10, No. 2 April 1995. Using reactors to reduce in-rush current reduces restrike probability. The contact material used in these switches is copper tungsten the same as reported to have the lowest restrike probability in this Toshiba paper.