Overview

Output surge arrestors are installed on the CCR output side. Their purpose is to protect the regulator and associated components from transient voltage conditions originating on the series lighting circuit.

Primary Function

The output surge arrestors limit transient overvoltage conditions. They protect internal transformer and control components. They help reduce damage caused by lightning or switching events on the field circuit. The series circuit can experience transient events due to lightning strikes near airfield circuits, cable faults, switching operations, or ground disturbances. The arrestors provide a path to divert excessive voltage.

Location in the System

Output surge arrestors are connected on the regulator’s output terminals. They operate independently of the DCMU and control system. Their function is protective, not regulatory.

Protection Scope

The output surge arrestors protect the ferroresonant transformer windings, SSR circuitry, firing card, current transformers, and other internal components exposed to output voltage. They do not regulate output current during normal operation. They only respond during transient conditions.

Interaction with Open-Circuit Conditions

The surge arrestors do not eliminate open-circuit voltage rise. They are intended to clamp transient spikes, not steady-state voltage conditions. Open-circuit hazards remain present even when surge arrestors are installed.

Service and Safety

Before servicing output components, de-energize input power. Follow proper lockout/tagout procedures. Verify absence of voltage. Output terminals may carry hazardous voltage. Surge arrestors are connected to the output circuit and must be treated as energized until verified safe.

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