The light falling on the moving parts of any machinery causes it to appear either to running slow or in reverse direction or even may appear stationary. This effect is known as the stroboscopic effect. The stroboscopic effect is an optical illusion.
Why Stroboscopic Effect Takes Place?
In alternating quantity, for every cycle of current or voltage waves, the waves pass through zero-crossing twice. In our electrical system, we have lamps or FTL supplied with 50 Hz or 60 Hz AC supply.
Suppose we are supplying an AC supply of 50 HZ. This means that with a supply frequency of 50 Hz, the lamp will turn off 100 times per second because for 50 Hz supply the voltage or current waves passes through zero-crossings 100 times per second. But, due to the persistence of vision, our eyes do not notice this turning off phenomenon which leads to the stroboscopic effect.
Minimizing the Effect
The following measures will help to minimize the stroboscopic effect:
- The FTL lamps or other luminaries which is to be used in the industries should not be connected in a single-phase only. This means that power to all the luminaries in a particular area of the industry should not be supplied from the same phase ( either from the R phase only or the Y phase only or From the B phase only).
For connecting the lamps or luminaries we should use different phase supplies. Such as an area that contains three lamps. Here, we can connect the lamps with different phases rather than connecting all the lamps from the same phase.
This ensures that, if we connect the lamps with different phase lines then the zero instance of the two lamps will not be the same and hence we can reduce the stroboscopic effect.
- What if there is only a single-phase supply available?
In such a case, where only a single-phase supply is available then we connect the lamps in parallel. Here, in the same connection, we will connect one of the lamps with a capacitor or condenser in series with a choke. This arrangement will provide a phase of the power being supplied to the lamps such that the zero crossings of the two lamps do not occur at the same instant and the stroboscopic effect is minimized.
This connection will also improve the power factor.