YORK YCAV — SYS X HIGH MOTOR CURRENT

The panel shows SYS X HIGH MOTOR CURRENT. In the manual's fault tables the message is printed as SYS X YYYYYYY HIGH MOTOR CURRENT: X is the system number, and the YYYYYYY field reads FAULT for a condition that restarts or LOCKOUT once the system has locked out. The manual lists it among the VSD safeties (faults) and treats it as an individual system/compressor fault on all units.

This is a hardware-generated VSD fault, not a soft control alarm. Three current transformers inside the VSD monitor the three output lines to each phase of the compressor motor, and the instantaneous output current is compared against a predetermined hardware limit. If the peak current limit is exceeded, the unit faults and shuts down immediately. Because it is an individual system/compressor fault, it concerns the compressor of the system whose number appears in place of X on the display.

• The instantaneous peak motor current on one or more phases exceeded the predetermined hardware limit that the VSD monitors through its three current transformers.
• The manual names no other cause. It notes only that the trip point varies between units as a result of component tolerances on the VSD Logic Board, which is why the trip level is given as a nominal value with a minimum and a maximum.

• Nominal peak current trip level: 575.5 Amps (554A min., 597A max.).
• On 380V AC 60 Hz and 400V AC 50 Hz units, the nominal peak current trip level is 649.5 Amps (626 Amps min., 674 Amps max.).
• The trip level is a predetermined hardware limit in the VSD; the spread between the minimum and maximum figures comes from component tolerances on the VSD Logic Board.

This is an auto-restart safety. After a trip the system restarts on its own, and the display shows the FAULT state. If the fault occurs a 3rd time within 90 minutes, the system locks out. A lockout will not restart until the operator clears the fault using the keypad. The manual describes no other reset for this fault.