This option is relevant for applications where the motor load and motor currents are very low, such as
lowering a lift. Selecting this option allows to prevent false motor phase detection due to low currents.
The drive performs a scan for 100 ms to detect missing motor phases.
N O T I C E
This option is only available in FC 302.
N O T I C E
The motor automatically resumes operation when the motor is reconnected.
This option allows disconnection of the motor with a service switch without issuing an alarm. The drive
coasts and automatically resumes operation when the motor is reconnected.
The following table details the detection of missing motor phase function for different motor control principles:
Table 299: Missing Motor Phase for Different Motor Control Principles
Missing motor
phase function
Motor check (serv-
ice switch)
Coasts if motor is disconnected or auto started when the motor is reconnected.
1
When parameter 4-59 Motor Check at Start is set to [1] On, then 3-phase detection is enabled for U/f and VVC+ motor control.
Parameter 4-59 Motor Check at Start
Table 300: Parameter 4-59 Motor Check at Start
4-59 Motor Check at Start
Change during operation: True
N O T I C E
Adjusting this parameter while the motor is running will not have effect until the next motor start.
This function detects missing motor phase before each start. Shows alarm 30, alarm 31, alarm 32 if motor phases are missing. In
these cases, the drive trips and an alarm is issued. The function has been developed to avoid disengaging a mechanical brake if
motor phases are missing, for example, in lift applications.
AU275636650261en-000101 / 130R0334 | 167Danfoss A/S © 2022.12
Parameter Descriptions
VLT AutomationDrive FC 301/302
Programming Guide