how can the load current taken by the ceiling fan or 100w bulb be calculated if the AC input is 220v. can we calculate the resistance of Ceiling fan and 100 watt bulb?

 

hmm, P = V* I ---> I = P/V

 

Easiest is to just read the watt rating on the nameplate on the ceiling fan or the rating on the lightbulb.. This will get you pretty close. Now sure how close you need to be though.

But using Ohms law. 100W/220V=.45 Amps at 120V it would be 100W/120=.83 Amps

 

And Bear in mind that resistance of a light bulb is highly nonlinear.
See the graph of resistance of a 100W/230V light bulb in function of a supply voltages.
Resistance for 230V is equal 530Ω so current is equal 0.434A
But for 120V the current will be equal:
I = 120V/ 380Ω = 0.315A

 

Very simple use a Amp meter.Now for the bulb the resistance is constant so using ohms law will do the job .But for the fan its not so simple because the fan is made using coil i.e.. inductor and also its run under singal phase so we add a capacitor to make two phase ,Now we could see that ,its a inductive come capacitive circuit so the the total impedance is the resistance here.Its calculated using Complex numbers which is quite different then scaler calculation.

Good Luck

 

hmm, P = V* I ---> I = P/V

Thanks for idea but sir how can be the wattage rating of fan calculated because it is inductive load and what is apparent power

 

And Bear in mind that resistance of a light bulb is highly nonlinear.
See the graph of resistance of a 100W/230V light bulb in function of a supply voltages.
Resistance for 230V is equal 530Ω so current is equal 0.434A
But for 120V the current will be equal:
I = 120V/ 380Ω = 0.315A

Thanks a lot sir.Sir can we say that the resistance of bulb varies due to the varying ac voltage therefore it is nonlinear resistance.

 

Very simple use a Amp meter.Now for the bulb the resistance is constant so using ohms law will do the job .But for the fan its not so simple because the fan is made using coil i.e.. inductor and also its run under singal phase so we add a capacitor to make two phase ,Now we could see that ,its a inductive come capacitive circuit so the the total impedance is the resistance here.Its calculated using Complex numbers which is quite different then scaler calculation.

Good Luck

Thanks for such a nice guidance.Sir can we say that the fan and capacitor make a LC circuit.

 

Thanks a lot sir.Sir can we say that the resistance of bulb varies due to the varying ac voltage therefore it is nonlinear resistance.

No.. the filaments (the part of a lightbulb that glows) resistance changes depending on its temperature.

 

Thanks for such a nice guidance.Sir can we say that the fan and capacitor make a LC circuit.

Yes it forms a LC circuit,Google about "poly phase ac induction motors" .The motor have two coils (in real many all interconnected to form two coils) 90 degree apart from each other and connected in series with each other and the capacitor is connected in parallel with these coil.

I am just a student ,so no Sir just debjit625

Good Luck

 

No.. the filaments (the part of a lightbulb that glows) resistance changes depending on its temperature.

Thanks a lot Sir

 

No.. the filaments (the part of a lightbulb that glows) resistance changes depending on its temperature.

Thank a lot Sir

 

you are teaching something to me therefore you are teacher or Sir for me and I am your student.