Overview

The control transformer provides low-voltage power for the CCR control circuitry. It steps down the incoming line voltage to supply power for control circuits, DCMU, firing card, input contactor coil, and remote control circuitry. The control transformer is separate from the main ferroresonant transformer used for output regulation.

Output Voltages

The control transformer provides 15 VAC for internal control functions and 120 VAC for certain control and remote interface functions. These voltages power the regulation and monitoring electronics.

Function Within the System

The control transformer supplies operating power to the DCMU, energizes the input contactor coil, provides reference voltage for control logic, and supports remote control input circuits. Without proper control transformer output, the CCR will not operate correctly.

Startup Behavior

When input power is applied, the control transformer energizes. Control circuits power up. The DCMU display becomes active. The system becomes ready to receive ON/OFF commands. If control voltage is absent, the display may not power up, the input contactor may not energize, and the CCR may appear inoperative.

Isolation and Safety

The control transformer provides electrical isolation between line voltage input and low-voltage control circuitry. Even though control voltages are lower than output circuit voltage, they must still be treated as energized circuits until verified safe.

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