Danfoss VLT MCD 600 Operating Manual page 130

Operating Guide | VLT® Soft Starter MCD 600
Troubleshooting
• For the soft starter and the motor, check
- The supply connections.
- The input connections.
- The output connections.
• There are no parameters related to this trip message.
12.2.23 L1-T1/L2-T2/L3-T3 Shorted
Cause
During pre-start checks, the soft starter has detected a short-circuited SCR or a short circuit within the bypass contactor as indicated.
Troubleshooting
• Consider using PowerThrough to allow operation until the soft starter can be repaired.
• See also parameter 6-19 Shorted SCR Action.
12.2.24 Low Control Volts
Cause
The soft starter has detected a drop in the internal control voltage. This protection is not active in ready state.
Troubleshooting
• Check the external control supply (terminals A7, A8, A9) 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
- Check if the bypass driver PCB is faulty. Contact the local supplier for advice.
• There are no parameters related to this trip message.
12.2.25 Low Flow
Cause
The flow sensor connected to the smart card has activated low-flow protection. Related parameters:
Troubleshooting
• Check the following parameters:
Parameter 30-5 Flow Sensor Type.
-
- Parameter 30-7 Flow at 4 mA.
- Parameter 30-8 Flow at 20 mA.
- Parameter 31-2 Low Flow Trip Level.
- Parameter 31-3 Flow Start Delay.
- Parameter 31-4 Flow Response Delay.
- Parameter 36-7 Low Flow.
130 | Danfoss A/S © 2018.10
Troubleshooting
AQ262141844215en-000202 / 175R1174