Gunwant Singh

There are two kinds of appliances: 1) Without Motor (resistive load) and 2) With Motor (inductive load). Appliances without motor include Bulbs/Tube lights/CFLs, water heaters and room heaters / TVs/Music Systems/DVD/Home Theatre/ Laptops/Phones. Appliances with motor include Air Conditioners/Refrigerators/Ceiling Fans/Mixer Grinders/Pumps/Washing Machines. When the voltage is less, less current flows through them. When voltage is more, more current will flow through them. So when voltage is less, the output of these appliances will be less or the bulb will give less light, room heater will heat less, water heater will heat slowly. And as the bulb will give lesser light the power consumption of the bulb will be less. Most electronics like TVs, DVD players, etc do not work at 230 V. These appliances have an internal device called SMPS (Switch Mode Power Supply) which converts incoming 230 V to 12V or 24V (whichever is required by the appliance). The power consumption of electronic products does not change with voltage changes. All appliances with motors have an operating voltage range. Appliance like a ceiling fan have much larger operating voltage range and thus they are able to work even at lower voltages. But appliances like air conditioners have very small operating voltage range and thus they do not work at low voltages. If the voltage provided to them is lower than their operating voltage range, then either they will not start at all, and if they are already running, they will start producing a humming sound. This humming sound happens as these motors draw more current to run the system. At high voltages these appliances draw more current only at the time of starting, but once they reach steady state the current is much less.

Tube Light emit light according to the frequency (50 Hz) of the main supply (that is, the lamp is on for few milliseconds, goes off for the next few milliseconds, and the process repeats 50 times a second). But we don't see the on-off processes because of our eye's persistence of vision. (The eye has the ability to retain the impression of an image for short time even after the image has disappeared). But sunlight and candle light are continuous without periodically going off and on. Hence when the light goes off, the eye involuntarily retains the image of the fan blades. Again when the light comes on, the fan’s blades would have moved to a new position and the eye records a new image. Depending on the speed the fan, the image retained by the eve gives us the illusion. Supposing we make a fan rotate at a speed of 50 rpms and see it under a tube light, the fan would appear to be stationary. If the speed is different from 50 rpm, the fan seems to rotate slowly forwards or backwards depending on the speed.

so that equipment is connected to earthing for safety of equipment and person who is plugging the electrical plug before it is connected to supply voltage through other two smaller pins. earthing pin is also thicker than other two pins, this is to safely handle extra current in case of problem in the equipment.