Constant Current Regulator Overview

The ferroresonant constant current regulator uses a ferroresonant transformer system to maintain constant current in an airfield lighting series circuit. The CCR adjusts output voltage automatically to maintain a constant programmed current level. The CCR is connected to a series lighting circuit. In a series circuit, the same current flows through all fixtures. Load changes affect voltage, not current. The regulator maintains constant current by automatically adjusting output voltage in response to changes in load. If the load increases, output voltage rises. If the load decreases, output voltage drops. This maintains the programmed current setting.

Description of Main Components

The ferroresonant CCR consists of ferroresonant transformer, capacitor bank, solid state relay (SSR), firing card, digital control and monitoring unit (DCMU), current transformers (CTs), input contactor, and control transformer. The ferroresonant transformer is the primary current-regulating element of the system. The ferroresonant transformer works in combination with a capacitor bank to create a resonant circuit. The SSR controls current by regulating the energy delivered to the transformer. The SSR operates under the direction of the firing card and DCMU to maintain the selected brightness step. The firing card provides control signals to the SSR. The firing card determines the appropriate conduction timing to achieve the programmed output current. The DCMU interfaces with the keypad and display, processes control inputs, monitors system performance, logs faults and warnings, and manages brightness steps. In the L-829 model, additional monitoring functions are integrated. Current transformers monitor output current. Feedback from CTs is used by the control system to maintain accurate regulation. Optional input CTs may be used for monitoring input current. The CCR operates in either 3-step configuration (Style 1) or 5-step configuration (Style 2). Each step corresponds to a defined percentage of full output current.

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