Motor phase U missing
Danfoss · VLT HVAC Basic FC 101
¿Qué significa ALARM 30 ?
The motor phase U connection between the frequency converter and the motor is missing or interrupted. This prevents proper motor operation and can lead to damage if ignored.
Causas comunes
- Loose or disconnected conductor at the drive output terminal U.
- Loose or disconnected conductor at the motor terminal U.
- Break or high resistance in the motor cable's U phase conductor.
- Faulty contactor or circuit breaker in the motor output circuit (if present) for phase U.
- Failure of the drive's output power stage (e.g., IGBT) specifically for phase U.
Pasos de reparación & Lista de verificación
Haga clic en los pasos para seguir su progreso.
- 1
Power off the drive and disconnect input power. Visually inspect and tighten connections for the U-phase motor cable at both the drive's U output terminal and the motor's U terminal.
- 2
Measure the resistance of the U-phase motor cable conductor from the drive end to the motor end to check for continuity (expect < 1 Ohm).
- 3
With motor cables disconnected from the drive, measure the resistance between motor terminals U-V, U-W, and V-W. All three values should be balanced and low.
- 4
Check for any external fusing or contactors in the U-phase motor circuit for continuity and proper operation.
- 5
If cable and motor are verified good, the fault indicates a potential internal drive hardware issue with the U-phase output.