Mains Transient Over voltage:-

The test parameters says that “Main transients of either polarity, randomly phased and superimposed on the mains voltage, as specified below, shall not disturb the intended functioning of the equipment or lead to damage. Direct influence of lighting off the mains distribution has not been taken into account”. “The pulses to be applied in symmetrical, differential or series mode (that is, from phase to neutral or from phase to phase) and in asymmetrical or common mode (that is, from phase to system ground and/or protective earth)”.

Since the ballast does not have a ground terminal, pulses need only be applied at symmetrical mode as per the test parameters. The pulse amplitude is 1000 V and the Pulse Rise time is 100 nano seconds with a pulse width of 50 micro seconds. The maximum energy is 2 J and the reception rate is 160 ms (1/8 th of mains frequency). The mains voltage is 230V AC. The equipment used is Schaffner NSG 223A. During the course of the test the pulse phase is continuously changed from 0⁰ to 360⁰ by slowly moving the nobe from one extreme phase position to the other and slowly back during 1 minute; and this procedure is repeated for both positive and negative polarities. There was no lamp flicker observed during the entire course of the test, and there was no damage to the ballast operating the lamp. In other words the lamp ballast combination is totally undisturbed by the transient pulses that was superimposed over the main supply voltage, as done in this test. For an unearthed ballast, this test is very important as this ascertains the ability of ballast to withstand the transient pulse without the need of a earth terminal, the presence of which would seriously affect the practical application of the product on a wide basis.