Overview

If the CCR does not turn on when commanded, the issue may be related to control voltage, fuses, configuration, fault conditions, remote control wiring, or contactor operation. This article provides a systematic approach to diagnosis.

Verify Display Power

If the DCMU display is blank, verify input voltage is present. Inspect F1 and F2 (control transformer primary fuses). Inspect F3 (15 VAC secondary fuse). Measure control transformer secondary voltage (terminals 11–12). If the display is powered.

Check for Active Faults

Press the FAULT button. If a fault is present, identify the fault description. Correct the underlying issue. Reset or restart the CCR as required. Active faults may prevent startup.

Verify Mode Selection

Confirm the CCR is in the correct mode. If using front panel control, ensure LOCAL mode is selected. If using remote control, ensure REMOTE mode is selected. If in Local mode, remote commands will not operate the CCR.

Verify Contactor Operation

Press ON. Verify the input contactor energizes. Verify no abnormal noise is present. Verify no immediate shutdown occurs. If the contactor does not energize, inspect F4 fuse (contactor circuit). Verify 120 VAC control transformer output. Inspect contactor coil wiring. Verify S-1 cutout position.

Verify Remote Configuration (If Applicable)

If operating in Remote mode, confirm remote input voltage setting (24V or 120V). Inspect remote wiring continuity. Verify correct internal vs external configuration. Inspect F5 fuse (120V internally powered systems only). Improper remote configuration is a common cause of startup failure.

Inspect Output Circuit Condition

If the CCR energizes but output current is zero, verify series circuit continuity. Inspect S-1 cutout handle position. Check for Output Disabled warning. An open series circuit may prevent proper operation.

Review Diagnostic Data

Access the Diagnostics menu and verify output current reading, internal reference values, and input voltage status. Abnormal values may indicate control circuit issues.

Common Causes Summary

A CCR that will not turn on is commonly caused by blown F1, F2, F3, or F4 fuses, incorrect remote voltage configuration, CCR left in wrong operating mode, active fault condition, open series circuit, or failed contactor coil.

Safety Reminder

The CCR contains hazardous voltage even when output is off. Always follow lockout/tagout procedures before servicing internal components.

 

Airport Lighting Company | Type L-828, Type L-829 Ferroresonant Constant Current Regulator