What is CCR testing?
Proving that a constant current regulator delivers the right current at every brightness step, protects itself and its circuit, and reports faults correctly.
A constant current regulator (CCR) must give each brightness step its rated current, whatever the circuit load. CCR testing proves it. The input supply is checked, the output circuit insulation is measured, and the output current is read at every step with a calibrated true-RMS meter and compared with the rated value. Regulation is then checked as the load or supply changes.
The last group of tests covers protection and alarms: open-circuit, overcurrent and earth-leakage conditions are simulated, following the manufacturer’s procedure and normally on a dummy load or test set rather than the live field circuit, to confirm the CCR responds and signals correctly, along with local and remote control. Because the output can reach high voltage, the CCR is isolated, locked out and proved dead before any output connection is changed, and it is never run with its output open.
- Prepare. Identify the CCR and circuit, get the permit-to-work and gather calibrated instruments.
- Isolate & connect. Lock out, prove dead, then fit the test connections or a dummy load.
- Check input. Confirm supply voltage and phases are within the CCR rating.
- Test insulation. Measure output circuit insulation resistance with the CCR disconnected.
- Energise & measure. Read output current at each brightness step against the rated value.
- Prove protection & record. Check regulation, protection, alarms and controls, then log results against the baseline.
Frequently Asked Questions
Q1What is CCR testing in airfield lighting?
The set of checks that prove a constant current regulator works as specified: input supply, insulation, output current at each brightness step, regulation under changing load, and its protection, alarm and control functions.
Q2When is a CCR tested?
At the factory and on site before acceptance, during commissioning, after any repair or replacement of major parts, and periodically as part of the maintenance programme.
Q3Why is output current checked at every brightness step?
Light output depends on lamp current. Each step must deliver its rated current within tolerance, so the lights show the correct intensity at every setting. It is measured with a calibrated true-RMS meter.
Q4What is a regulation test?
It confirms the output current stays within tolerance as the load or the input voltage changes. On site this is checked on the real circuit; on the bench a dummy load or load bank is used.
Q5How are protection functions proved?
By simulating the condition under the manufacturer’s test procedure, normally on a dummy load or test set rather than the live field circuit, for example an open circuit, an overcurrent or an earth leakage, and confirming that the CCR protects itself and raises the correct alarm. An energised output is never opened on a field circuit to prove open-circuit protection.
Q6Why must the output never be opened while the CCR is energised?
The CCR keeps driving its set current. An open output can produce a dangerously high voltage. Output connections are changed only with the CCR switched off, locked out and proved dead, or with a proper dummy load fitted.
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