TAVRIDA ELECTRIC VCB Series, User Manual

Page: 98 / 142

98
Opening
To open the ISM main circuits, a trip command should be applied to the CM trip command input. It is a “dry
contact“ input so no external voltage should be applied. The trip command will be accepted if:

CM state is “Ready” (Ready LED flashes green) or within 60 seconds after the removal of the auxiliary
power supply;

optional electrical interlock is unlocked;

mechanical and electrical interlock is unlocked (in case of ISM15_MD_1, ISM15_MD_3, ISM15_Shell_2
and ISM15_HD_1 only)
If the trip command is applied and kept before the CM is in a “Ready“ state, the
trip command will not be accepted.
Emergency opening
The ISM can also be opened manually. When the synchronizing shaft is rotated, a force exceeding the
magnetic attraction forces of the ring magnet is applied to the armature, which subsequently starts to move.
As the air gap increases, the opening springs and the contact pressure springs overcome the magnetic holding
force, and the vacuum interrupter opens.
To open the ISM15_LD_1, LD_3, LD_6 and ISM25_LD1, LD_2, LD_3 manually, the force shall be applied to
the interlocking pins or torque shall be applied to the stub shaft evenly during their movement - see Figure
158
. Force shall be applied along the pin‘s movement axis and directed to the ISM frame. The torque shall be
applied in the direction of shaft rotation during ISM opening. The force or torque influence shall not be applied
at the end of pin‘s stroke or shaft rotation and shall not be applied to the pin or shaft before ISM closing.
Figure 158
ISM15_LD_1, LD_3, LD_6 and ISM25_LD1, LD_2, LD_3 manual trip execution.
Force or torque can be applied to any of the points shown above
To open the ISM15_LD_8, ISM15_MD_1, ISM15_MD_3, ISM15_Shell_2 and ISM15_HD_1 manually, the
torque shall be applied to the interlocking shaft evenly during its movement - see Figure 159. The torque shall
be applied counterclockwise of shaft rotation (90 degrees angle). The torque shall not be applied at the end of
shaft rotation. ISM15_LD_8, ISM15_MD_1, ISM15_MD_3, ISM15_Shell_2 and ISM15_HD_1 have a built in
electrical interlock that interrupts the ISM coil circuit after the interlocking shaft is rotated counterclockwise.
After manual trip, the shaft should be rotated clockwise to unlock the ISM.