Danfoss · VLT 2800 Variable Speed Drive
This alarm appears when the adjustable frequency drive has been connected to the AC line supply too many times within a short period (1 minute). This typically indicates repeated power cycling that can stress internal components.
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Immediately cease all manual power cycling attempts of the drive's AC input supply.
Inspect the main input contactor (if present) for proper operation; check auxiliary contacts for reliability and ensuring it isn't chattering.
Review the control logic (PLC program, relay logic) that controls the drive's AC input power; ensure a minimum delay (e.g., 5 minutes) is implemented between power cycles.
Measure the AC line voltage at the drive's input terminals (L1, L2, L3) during operation to detect intermittent sags or drops using a logging multimeter.
Allow the drive's internal inrush current limiting circuit (e.g., precharge resistors) adequate time to cool and reset before reapplying power.
If an external circuit is used for power ON/OFF, ensure it provides a stable and continuous connection rather than repeated pulses.