.stroboscopic effect .stoboscopic

The light falling on the moving parts of any machinery causes it to appear either running slow or in reverse direction or even may appear stationary. This effect is known as the stroboscopic effect.

Reason for Stroboscopic Effect:

In alternating current, for every cycle of current or voltage waves, the waves pass through zero-crossing twice. In our electrical system, we have lamps 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.

Methods to Avoid Stroboscopic Effect

This pattern of illusions is not allowed in industries as this may lead to accidents. This is the main reason Fluorescent lamps are not preferred in industries.

However, this effect occurs in three-phase as well as single-phase supply. It can be avoided by some simple techniques.

Method to Avoid Stroboscopic Effect in Three-Phase Supply

If the system is supplied with a three-phase supply, adjacent lamps should be fed with a different phase so that the zero instants of the two lamps will not be the same.

Method to Avoid Stroboscopic Effect in Single-Phase Supply

If single-phase supply is only available, then the connection of two adjacent lamps is made such that the two lamps are connected in parallel with the supply.

In one lamp connection, a capacitor or condenser is kept in series with the choke. This makes a phase shift and eliminate the stroboscopic effect