Purpose

Airfield circuits are designed to supply a constant current series output. To power numerous devices on a constant current series circuit, the constant current regulator (CCR) produces a high voltage across the output as needed to maintain constant current across varying loads within design limits. The CCR regulates constant current, not voltage. It is designed for 6.6 A (Class 1) or 20.0 A (Class 2) series circuits. The CCR shuts down on open circuit but does not turn off on short circuit. Protective devices are designed to protect equipment, not to protect personnel.

Brightness Step Configurations

Style 1 provides three brightness steps: B10, B30, B100. Style 2 provides five brightness steps: B1, B2, B3, B4, B5. Steps are selected via the local keypad using the LOCAL UP and LOCAL DOWN buttons or through remote control signals. Pressing LOCAL DOWN at the lowest step turns the CCR off. Remote control uses terminal blocks with connections B1 through B5 or B10 through B100. The CCR can be toggled between local and remote modes using the REMOTE button. The LED in the button illuminates if Remote is enabled. Pressing the REMOTE button while already in remote puts the CCR back into Local mode.

CCR Output Currents (Reference FAA AC 150/5345-10H Table 1)

For Class 1 (6.6 A maximum), 3 Steps:
- B10: Nominal 4.8 A (Allowable 4.7–4.9 A)
- B30: Nominal 5.5 A (Allowable 5.4–5.6 A)
- B100: Nominal 6.6 A (Allowable 6.5–6.7 A)
For Class 1 (6.6 A maximum), 5 Steps:
- B1: Nominal 2.8 A (Allowable 2.7–2.9 A)
- B2: Nominal 3.4 A (Allowable 3.3–3.5 A)
- B3: Nominal 4.1 A (Allowable 4.0–4.2 A)
- B4: Nominal 5.2 A (Allowable 5.1–5.3 A)
- B5: Nominal 6.6 A (Allowable 6.5–6.7 A)
For Class 2 (20.0 A maximum), 5 Steps:
- B1: Nominal 8.5 A (Allowable 8.2–8.8 A)
- B2: Nominal 10.3 A (Allowable 10.0–10.6 A)
- B3: Nominal 12.4 A (Allowable 12.1–12.7 A)
- B4: Nominal 15.8 A (Allowable 15.5–16.1 A)
- B5: Nominal 20.0 A (Allowable 19.7–20.3 A)

Verifying Output Current

Use a current clamp rated for the circuit current connected to a DMM. Clamp around one output lead. Use LOCAL UP and LOCAL DOWN buttons to cycle through each brightness step. Compare measured current to the nominal and allowable values listed. Never place a DMM directly across output terminals to measure voltage. Follow lockout/tagout procedures before accessing wiring. Only qualified personnel should perform measurements.

Important Safety Notes

The output current of the CCR is dangerous. It is designed to work in a 6.6 Amp or 20 Amp series circuit. Check the output current on the nameplate before working on the CCR. The nominal output voltage of the CCR can be as high as 4,545V on a 30kW CCR (30,000 / 6.6), or even greater in open-circuit instances. Check the output voltage on the nameplate before working on the CCR. Never put a DMM on the output circuit to measure voltage. Doing so may cause DMM failure and/or risk of electrical shock. Follow all local and national electrical codes for installation and service of the CCR. Only qualified service personnel should be allowed to install and service the CCR. Open all sources of electricity to the CCR. Follow lock out / tag out procedures to ensure continued safety while completing work. Verify correctness of work done with a second set of eyes before re-energizing the CCR.

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