Display Possible cause/Suggested solution
Heat sink overtemp Check that cooling fans are operating. If mounted in an enclosure, check if ventilation is adequate.
Fans operate during start, run, and for 10 minutes after the soft starter exits the stop state.
NOTICE
Models MCD5-0021B ~ MCD4-0053B and MCD5-0141B do not have a cooling fan.
Models with fans operate the cooling fans from a start until 10 minutes after a stop.
Related parameters:
•
Parameter 16-6 Heat sink Overtemp.
High level Name selected for a programmable input. Refer to Input A trip.
High pressure Name selected for a programmable input. Refer to Input A trip.
Input A trip The programmable input is set to a trip function and has activated. Resolve the trigger condition.
Related parameters:
•
Parameter 3-3 Input A Function.
•
Parameter 3-4 Input A Name.
•
Parameter 3-5 Input A Trip.
•
Parameter 3-6 Input A Trip Delay.
•
Parameter 3-7 Input A Initial Delay.
•
Parameter 16-8 Input A Trip.
Instantaneous overcurrent There has been a sharp rise in motor current, probably caused by a locked rotor condition (shear
pin) while running. Check for a jammed load.
Related parameters:
•
Parameter 2-6 Instantaneous Overcurrent.
•
Parameter 2-7 Instantaneous Overcurrent Delay.
•
Parameter 16-4 Inst Overcurrent.
Internal fault X The soft starter has tripped on an internal fault. Contact the local Danfoss supplier with the fault
code (X).
Related parameters: None.
L1 phase loss
L2 phase loss
L3 phase loss
During prestart, check that the soft starter has detected a phase loss as indicated.
In run state, the soft starter has detected that the current on the aected phase has dropped
below 3.3% of the programmed motor FLC for more than 1 s. This current drop indicates that
either the incoming phase or connection to the motor has been lost.
For the soft starter and the motor, check;
•
The supply connections.
•
The input connections.
•
The output connections.
A failed SCR can also cause phase loss, particularly an SCR that has failed open circuit. A failed SCR
can only be diagnosed accurately by replacing the SCR and checking the soft starter performance.
Related parameters: None.
L1-T1 shorted
L2-T2 shorted
L3-T3 shorted
During prestart checks, the soft starter has detected a short-circuited SCR or a short circuit within
the bypass contactor as indicated.
Related parameters: None.
Low control volts The soft starter has detected a drop in the control voltage.
•
Check the external control supply (terminals A4, A5, A6) and reset the soft starter.
If the external control supply is stable:
•
Check if the 24 V supply on the main control PCB is faulty; or
•
If the bypass driver PCB is faulty (internally bypassed models only).
This protection is not active in ready state.
Related parameters:
•
Parameter 16-13 Low Control Volts.
Troubleshooting Operating Guide
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