What is a transformer’s circuit position?
A transformer's circuit position is where its primary winding sits in the series loop. Every light on a circuit is one link in the chain, and the same constant current passes through all of them.
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A transformer’s circuit position is where its primary winding sits in the series loop. Each light on a circuit has its own isolation transformer, and every primary is a link in one chain: out from the constant current regulator (CCR), through each transformer in turn, and back to the CCR. Because it is a single loop, the same constant current flows through every primary, whether it is first, last or in the middle.
What a position changes is the order of the lights along the cable, and which neighbours a transformer is joined to. It does not change the current. The voltage across each primary depends on that transformer’s own load, and the CCR has to supply the total of all the primary voltages plus the voltage lost in the cable. Some layouts alternate neighbouring lights between two or more circuits, so the position also tells you which circuit a light belongs to. Because the loop is one chain, a break anywhere stops every light on the circuit: isolate and make the circuit safe under site procedures before working at any position.
Frequently Asked Questions
Q1What is a transformer’s circuit position in AGL?
Where its primary winding sits along the series loop that runs out from the constant current regulator (CCR), through the transformer of each light in turn, and back to the CCR. Each light’s transformer is one link in that chain.
Q2Does the position along the circuit change the current a transformer carries?
No. A series circuit is a single loop, so the same constant current flows through every primary winding. What each transformer adds to the circuit depends on its own load, not on whether it is first, last or in the middle.
Q3What happens to the other lights if the loop is broken at one transformer?
Opening the loop anywhere stops current in the whole circuit, so every light on it goes out. This is why the circuit is isolated at the CCR, locked off and proved dead before any primary lead is disconnected, and why the primary path must be complete again before the circuit is re-energised.
Q4Why are lights sometimes split across more than one circuit?
Some layouts alternate neighbouring lights between two or more circuits, so a circuit fault leaves a pattern of lights still working instead of one dark stretch. The design drawings show which circuit each transformer belongs to.
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