Electrical Switchboard Control Failure — Causes and Quick Fixes
When your electrical switchboard fails to respond to control signals, operations can come to a halt. Here’s how to diagnose and fix the issue step by step:
1. No Control Power Supply
Cause: Blown fuse, tripped MCB, or missing DC voltage. Fix: Verify control voltage at the terminals. Replace fuses and reset the control circuit breaker.
2. Loose or Broken Control Wiring
Cause: Damaged or disconnected wires between relays and coils. Fix: Inspect all terminal blocks, tighten connections, and check continuity using a multimeter.
3. Faulty Closing or Trip Coil
Cause: Coil burnout or open circuit. Fix: Measure coil resistance. Replace the coil if resistance is infinite or out of range.
4. Interlock Not Satisfied
Cause: Door, spring, or position interlock preventing operation. Fix: Make sure the breaker is in the correct test/service position, the spring is charged, and doors are securely closed.
5. PLC or Communication Fault
Cause: Faulty output module, IP conflict, or disconnected communication cable. Fix: Check PLC diagnostics, verify signal mapping, and test network connectivity (Ethernet or RS-485).
6. Relay Blocking or Trip Condition
Cause: Relay logic preventing close due to active protection trip. Fix: Review event logs, reset after confirming no active fault.
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