The CCR protection
The monitors and trips that guard a constant current regulator and its series circuit. Pick a fault, move the slider and see which device sees it, whether the CCR warns or shuts down, and what to check before any reset.
CCR protection works in layers: a breaker and surge protection at the input, a supply monitor, output current sensing, a temperature sensor and an insulation monitor. They report to the control board, which can open the contactor and shut the output down.
Critical faults, such as an open circuit, overcurrent or over-temperature, shut the output down. Warnings, such as low insulation, let the lights keep running while the cause is found. After a trip, find and correct the cause before resetting; repeated resets can hide a hard fault on a high-voltage circuit.
Frequently Asked Questions
Q1What is CCR protection for?
To protect people, the series circuit and the CCR itself. Monitors watch the supply, the output and the temperature, and the CCR either raises an alarm or shuts down its output.
Q2Which faults shut the CCR down and which only warn?
Critical faults such as an open circuit, overcurrent, over-temperature or a supply far outside its limits shut the output down. Conditions such as current slightly out of tolerance or low insulation raise a warning and let the lights keep running while the cause is found.
Q3Why does an open circuit shut the output down?
The CCR keeps trying to push the set current into a loop that is no longer complete, so the output voltage would rise far above normal. Shutting down removes that hazard to people and insulation.
Q4Why does an earth fault only warn?
The series loop is isolated from earth, so one earth fault does not normally stop the lights. It is still serious: a second fault can cause a hard short and a shock hazard, so it should be found and repaired early.
Q5Should a tripped CCR be reset straight away?
No. Record the code and readings, isolate and lock out, find and correct the cause, then reset. Repeated resets can hide a short, an open circuit or an earth fault on a high-voltage circuit.
Q6How are protection functions checked?
During testing and maintenance, under the manufacturer's procedure and a permit to work, with the CCR disconnected from the airfield circuit, for example to confirm the open-circuit trip. A live series circuit is never opened to test protection. See CCR Testing.
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