Troubleshooting; Protection Responses; Trip Messages - Danfoss VLT MCD 600 Operating Manual

Operating Guide | VLT® Soft Starter MCD 600

12 Troubleshooting

12.1 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 [Reset] 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.

12.2 Trip Messages

12.2.1 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.
12.2.2 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.
12.2.3 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.
124 | Danfoss A/S © 2018.10
Troubleshooting
AQ262141844215en-000202 / 175R1174