How are transformers maintained?
With the circuit isolated, a transformer is inspected, its leads and connectors checked, its pit kept clean and dry, and its insulation and windings tested, with every result recorded to show the trend.
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Transformer maintenance keeps a series isolation transformer sound and finds problems before they cause a fault. With the circuit isolated, locked off and proven dead, the transformer and its leads are inspected, the connectors checked, the pit kept clean, dry and draining, and the insulation and windings tested.
Every result is recorded against the transformer and compared with earlier readings and the manufacturer’s data, so a slow decline shows as a trend before it becomes an earth fault or an open circuit. Most trouble starts with water and damaged connectors, not the windings, so these get particular attention. For the insulation test, use no more than the manufacturer’s test voltage, disconnect any electronics such as LED drivers first, and discharge the winding afterwards. Before re-energising, confirm every connector is re-made and no secondary is left open-circuit. Intervals and methods follow the site maintenance programme and the manufacturer’s instructions.
Frequently Asked Questions
Q1What does transformer maintenance involve?
Inspecting the transformer and its leads, checking and re-making connectors where needed, keeping the pit clean, dry and draining, testing insulation and winding continuity, and recording the results. It is done with the circuit isolated.
Q2How often should transformers be maintained?
As set by the site maintenance programme and the manufacturer’s instructions. Frequency depends on the circuit, the environment and the transformer, so there is no single interval that suits every airfield.
Q3Why are connectors and the pit given so much attention?
Water and damaged connectors are a frequent cause of low insulation readings, flicker and open circuits, often while the windings themselves are fine. Keeping the pit dry and the connectors sound prevents many faults.
Q4Does the circuit have to be isolated for maintenance?
Yes. Isolate at the CCR, lock off, prove dead and earth as the site procedure requires before touching any transformer lead, because the series loop carries a high voltage and a live loop must never be opened.
Q5What do maintenance records add?
They let each reading be compared with earlier results and the manufacturer’s data. A slow fall in insulation or a changing winding reading is then seen as a trend and dealt with before it becomes a fault.
Q6When does maintenance lead to replacement?
When inspection or testing shows the transformer no longer meets the specification, when it is physically damaged, or when faults keep recurring after the leads and connectors have been put right. See Transformer Failure Modes.
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