Overview

The input contactor controls the application of input power to the CCR. It is an electrically controlled switching device that connects or disconnects facility power from the regulator’s internal circuitry.

Primary Function

The input contactor connects incoming line voltage to the regulator when the CCR is turned ON. It disconnects input power when the CCR is turned OFF. It is controlled by the CCR control system. It provides controlled energization of the transformer and associated components.

Operation During Start-Up

When the CCR is commanded to turn ON, the control system energizes the contactor coil. The contactor closes. Input power is applied to the regulator. When the CCR is turned OFF, the coil is de-energized. The contactor opens. Input power is removed from the main power circuit.

Relationship to Control System

The input contactor operates under control of the DCMU and associated circuitry. It does not operate independently. It responds to local ON/OFF commands, remote control inputs, and fault conditions. If certain fault conditions occur, the control system may de-energize the contactor.

Safety Considerations

Even when the contactor is open, upstream input terminals may still be energized. Lockout/tagout is required before servicing. The input contactor does not replace upstream disconnect devices.

Mechanical Wear

Unlike the SSR, the input contactor is a mechanical device. It may experience contact wear over time, coil failure, and mechanical fatigue. Periodic inspection and maintenance may be required.

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