Why lighting transformer Used for lighting loads?
Lighting transformer is nothing but a 1:1 transformer or step down transformer with step reduction of appx. 0 to 10 %, Which means the transformer comes with the adjustable tappings to reduce the output voltage of the transformer.
Main purpose of lighting transformer is
Power Save using lighting transformer:
The ultimate aim of the lighting transformer is to Reduce the voltage for the lighting loads. As we know the AC power P= V* I * Cosθ. Here the voltage is directly proportional to the Power. Also the reduction of voltage may elevate the current flow through the circuit, but in lighting load reduction of 10% of voltage increases only 5 % of the current hence the net power consumption gets reduced.
Ensuring the Neutral availability:
In three phase delta secondary connected transformer do not have neutral point. Hence in order to use the power supply we have to install lighting transformer with secondary star configuration (star have wide advantage over delta connection).
Isolation of Lighting loads
The lighting loads should not be connected with the PCC or MCC panel. Because in Industry, lighting circuits may or may not be organized, due to that we get frequent tripping of the lighting circuits. therefore, these small fault may have chance of tripping of MCC or PCC circuit breakers. So that by providing separate lighting system, we can create good relay co-ordination with the PCC for system stable operation.
Reduction of Voltage flickering:
In an Electrical PCC or MCC panel, voltage flickering will be created by large inductive loads. Voltage flickering may reduce the lighting performance.