YORK YK — VSD - High phase A, B, C instantaneous current

The panel reads VSD - High phase A, B, C instantaneous current. The manual prints this single wording with no variants. It is listed among the Variable speed compressor drive cycling fault messages and applies to TM, VSD, and LVSD model drives.

This shutdown is generated by the VSD if the motor current on that phase exceeds a given limit. The motor current is sensed by current transformers on the VSD output pole assemblies, and the signals are sent to the VSD logic board for processing. The limit that applies depends on the drive model (see the thresholds below).

• A voltage sag on the utility power feeding the VSD, in excess of the specified voltage range for this product. This is the cause when the chiller trips but then restarts and runs without an issue, and it is especially true if the chiller was running at or near full load. When the line voltage dips suddenly, the current to the motor increases.
• An output pole problem — the most likely cause if the chiller keeps tripping on this shutdown.

1. Note whether the chiller was running at or near full load when the trip occurred.
2. Restart the chiller and observe whether it runs without an issue.
3. If the restart succeeds and the chiller runs fine, the cause was a voltage sag on the utility power feeding the VSD; the manual indicates no further action.
4. If the chiller does not restart and keeps tripping, an output pole problem is the most likely cause and the VSD requires service.

Table 178 of the manual gives the maximum instantaneous permissible currents per TM/VSD/LVSD drive model:

• 351/292 — 771 A
• 503/419 — 1,200 A
• 790/658 — 1,890 A
• 1055/914 — 2,749 A
• 1300/1100 — 3,265 A

The manual gives no separate reset procedure for this message. It is a cycling fault, so the chiller can be restarted after the trip; if it then runs without an issue, no further action is indicated. If this cycling shutdown occurs three times in 90 min, the third shutdown becomes a safety shutdown. A chiller that does not restart and keeps tripping needs the VSD serviced.