YORK YK — VSD - High instantaneous current

The control center shows VSD - High instantaneous current. The manuals print this wording only — there are no variants. The message comes from the medium voltage variable speed drive (MVVSD): it first appears in the drive's cycling fault list, and once it has occurred three times in 90 min it is also listed among the drive's safety faults.

The drive continuously monitors the instantaneous current it delivers to the motor. Two of the three output lines, T1 and T3, are measured by two DC current transformers within the drive; the third phase, T2, is derived. The three phases of instantaneous output current are continuously compared to an instantaneous limit of 233% of the drive's 100% FLA rating. If the peak instantaneous current trip limit is exceeded, the drive initiates a cycling shutdown. When the cycling fault has occurred three times in 90 min, the same message becomes a safety fault.

• The peak instantaneous current trip limit was exceeded: one or more phases of instantaneous output current rose above the instantaneous limit of 233% of the drive's 100% FLA rating.
• Repetition: the message escalates from a cycling fault to a safety fault once the cycling fault has occurred three times in 90 min.

• Instantaneous trip limit: 233% of the drive's 100% FLA rating.
• Safety fault escalation: the cycling fault occurring three times in 90 min.
• MVVSD instantaneous current limits — peak instantaneous motor over current trip, 2,300 V 60 Hz models (Horsepower rating — trip): 500 — 250; 600 — 301; 700 — 366; 800 — 401; 900 — 471; 1,000 — 523; 1,250 — 653; 1,500 — 784; 1,750 — 915; 2,000 — 1,022; 2,250 — 1,153.
• Peak instantaneous motor over current trip, 3,300 V 50/60 Hz models: 500 — 182; 600 — 219; 700 — 257; 800 — 292; 900 — 329; 1,000 — 364; 1,250 — 455; 1,500 — 548; 1,750 — 639; 2,000 — 728; 2,250 — 805.
• Peak instantaneous motor over current trip, 4,160 V 60 Hz and 6,600 V 50/60 Hz models: 500 — 145; 600 — 173; 700 — 203; 800 — 231; 900 — 261; 1,000 — 289; 1,250 — 362; 1,500 — 434; 1,750 — 506; 2,000 — 579; 2,250 — 639.

As a cycling fault, the message needs no manual reset: it clears automatically when the fault condition no longer exists, and if the chiller was running when the fault occurred, it automatically restarts. Once the fault has become a safety fault, the manual's instruction is: The chiller can be started after the fault is cleared on the starter, and the Clear button is pressed next to the listed event on the Systems Details screen. The companion manual describes the same recovery as pressing the CLEAR FAULT key on the OptiView display.