YORK YK — VSD - High DC bus voltage

On the display the message reads VSD - High DC bus voltage. The manual lists it under the variable speed compressor drive cycling fault messages for this chiller and prints it in this one form only, so there are no alternative wordings of the message to expect on the panel.

The VSD continuously monitors the voltage on its DC bus. When that monitored level exceeds the limit for the drive, the drive initiates this shutdown and the message appears on the panel. The manual describes the monitoring the same way for all model drives covered by this message, and the limit that applies depends on the drive model and the line voltage of the unit. The trip thresholds are listed in the settings section below.

• The VSD DC bus voltage exceeded the limit while being continuously monitored — this applies to all model drives.
• The manual ties the shutdown to the incoming supply: it directs you to look at the level of the 460 VAC applied to the drive, and voltage in excess of 508 VAC is the condition it tells you to correct.

1. When this shutdown occurs, the manual's instruction is to look at the level of the 460 VAC applied to the drive.
2. Compare the incoming voltage with the specified range for that supply: 414 VAC to 508 VAC.
3. If the incoming voltage is in excess of 508 VAC, take steps to reduce the voltage to within the specified limits.

High DC bus voltage threshold by line voltage and drive model:

• 380 VAC to 440 VAC TM/VSD/LVSD: 745 VDC
• 440 VAC to 460 VAC TM/VSD/LVSD: 745 VDC
• 575 VAC TM/VSD/LVSD: 909 VDC
• All HYP model drives: 985 VDC