Danfoss VLT MCD 600 User Manual

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11 Troubleshooting
11.1 Protection Responses
When a protection condition is detected, the soft starter writes this to the event log and may also trip or issue a warning. The soft
starter's response depends on the settings in parameter group 6-** Protection Action.
Some protection responses cannot be adjusted by the user. These trips are usually caused by external events (such as phase loss) or
by a fault within the soft starter. These trips do not have associated parameters and cannot be set to Warn or Log.
If the soft starter trips, identify and clear the condition that triggered the trip, then reset the soft starter before restarting. To reset
the soft starter, press [Back] on the LCP or activate the reset remote input.
If the soft starter has issued a warning, it resets itself once the cause of the warning has been resolved.
11.2 Trip Messages
11.2.1 2-Phase-damaged SCR
Cause
This message is shown if the soft starter has tripped on Lx-Tx shorted during the prestart checks and PowerThrough is enabled. It
indicates that the soft starter now operates in PowerThrough mode (2-phase control only).
Troubleshooting
Check for either a shorted SCR or a short within the bypass contactor.
Check also parameter 6-19 Shorted SCR Action.
11.2.2 Battery/Clock
Cause
A verification error has occurred on the real-time clock, or the back-up battery voltage is low. If the battery is low and the power is
off, date/time settings are lost.
Troubleshooting
Reprogram the date and time.
The battery is not removable. To replace the battery, the main control PCB must be replaced.
Check also parameter 6-20 Battery Clock.
11.2.3 Bypass Overload
Cause
This trip is not adjustable. Bypass overload protection protects the soft starter from severe operating overloads while running. The
soft starter trips if it detects overcurrent at 600% of the contactor rating. Related parameters: None.
Troubleshooting
There are no parameters related to this trip message.
11.2.4 Current at Stop
Cause
The soft starter has detected current at a time when no current is expected (ready, not ready, or tripped states).
Troubleshooting
If the motor is connected inside delta (6-wire connection) and no main contactor is installed, a short-circuited SCR may be pass-
ing current to the motor.
There are no parameters related to this trip message.
11.2.5 Current Imbalance
Cause
Problems with the motor, the environment, or the installation can cause current imbalance, such as:
An imbalance in the incoming mains voltage.
A problem with the motor windings.
A light load on the motor.
AQ262141844215en-000401 / 175R1174118 | Danfoss A/S © 2020.12
Troubleshooting
VLT® Soft Starter MCD 600
Operating Guide

Danfoss VLT MCD 600 Specifications

General

Brand	Danfoss
Model	VLT MCD 600
Category	Controller
Language	English