YORK YK — VSD - Gate driver - XYZ

The panel shows VSD - Gate driver - XYZ; the manual prints the message in this single form. The last three characters are placeholders the drive fills in to identify the switch that tripped: X denotes the power cell phase location (A, B, or C), Y denotes the location of the IGBT in the pole in relation to its connection (N, neutral or M, motor), and Z denotes the location relative to the internal neutral connection (U, upper or L, lower). Read the three printed letters to identify the phase, the pole connection and the upper or lower position of the IGBT that raised the shutdown.

This message is listed among the display messages of the medium voltage variable speed drive, in the group of cycling fault messages. The shutdown is generated when the voltage across the IGBT is too high. The gate driver board determines this shutdown and provides feedback to the MVVSD controller board that this shutdown occurred, and the drive initiates a cycling shutdown.

• The voltage across the IGBT is too high — the gate driver board makes this determination and provides feedback to the MVVSD controller board that the shutdown occurred.

The drive initiates a cycling shutdown, and no separate reset step is described for this message. Messages automatically clear when the fault condition no longer exists; if the chiller was running when the fault occurred, it automatically restarts. The message therefore leaves the display on its own once the fault condition is gone, and a chiller that was running at the time returns to operation by automatic restart.