204 questions

[PoorFish]

greetings All

Why would the voltage reading from a choke (inducter) in a flourescent light circuit and the voltage reading from a the lamp (resistance) not be the same as the supply voltage.

I know that this is to do with differing directions of phase angles but I thought I would get some other opinions on this.

Also why does the addition of a capacitor reduce the supply current?

I think it is to do with the fact that the capacitor charges up and the voltage increases and then the current is less.

Or would the answer simply be that this is power factor correction???

regards

P

 

[msb2003]

The choke voltage added to the lamp voltage do not add up to the supply voltage as the choke is an inductor and the voltage and current are out of phase. Draw a right angled triangle and put resistive voltage on one side(the lamp voltage), inductive voltage on the second side(the choke voltage) and the hypotenuse will be the supply voltage. It doesn't work out perfectly as the choke has a resistive element and is not a pure inductor.

The addition of the capacitor give the opposite effect on the current to the inductive choke and brings the current closer to being in phase with the voltage (yes this is pf correction)

hope that helps

 

[SPECIAL LOCATION]

The choke voltage added to the lamp voltage do not add up to the supply voltage as the choke is an inductor and the voltage and current are out of phase. Draw a right angled triangle and put resistive voltage on one side(the lamp voltage), inductive voltage on the second side(the choke voltage) and the hypotenuse will be the supply voltage. It doesn't work out perfectly as the choke has a resistive element and is not a pure inductor.The addition of the capacitor give the opposite effect on the current to the inductive choke and brings the current closer to being in phase with the voltage (yes this is pf correction)

hope that helps

That IMHO is on hell of a good answer Mr MSB2003!Applaud SmileyApplaud Smiley

Did I read somewhere you are in lecturing? :| ?:|

 

[SPECIAL LOCATION]

That IMHO is on hell of a good answer Mr MSB2003!Applaud SmileyApplaud SmileyDid I read somewhere you are in lecturing? :| ?:|

forget that....just read myself

Occupation Electrical installation lecturer

beers affecting me brain now!

 

[a1]

The choke voltage added to the lamp voltage do not add up to the supply voltage as the choke is an inductor and the voltage and current are out of phase. Draw a right angled triangle and put resistive voltage on one side(the lamp voltage), inductive voltage on the second side(the choke voltage) and the hypotenuse will be the supply voltage. It doesn't work out perfectly as the choke has a resistive element and is not a pure inductor.The addition of the capacitor give the opposite effect on the current to the inductive choke and brings the current closer to being in phase with the voltage (yes this is pf correction)

hope that helps

Gawd, I could have done with that reply from you when I did my 204 paperwork. I received a Credit on the 204. The reason: Because I did not explain why both v's did not add up to the vs, properly. Mind you I gave what I consider a good eplaination and a formula too.