Power Factor Question

[shnabz]

A 230V, single phase machine, draws a current of 10A at a power factor of 0.8. Calculate the power dissipated by the machine.

Is the answer 12.5A?

 

[Pete999]

A 230V, single phase machine, draws a current of 10A at a power factor of 0.8. Calculate the power dissipated by the machine.

Is the answer 12.5A?

Don't you mean power in KWs

 

[shnabz]

don't you mean power in kws

12.5 * 230 = 2.875kw

 

[Pete999]

A 230V, single phase machine, draws a current of 10A at a power factor of 0.8. Calculate the power dissipated by the machine.

Is the answer 12.5A?

It's drawing 10A at pf 0.8

 

[shnabz]

It's drawing 10A at pf 0.8

Yes, it is indeed drawing 10A at pf 0.8, but how much does this machine dissipate?

 

[Pete999]

Yes, it is indeed drawing 10A at pf 0.8, but how much does this machine dissipate?

you did the calcs with 12.5 amp and got an answer

 

[shnabz]

you did the calcs with 12.5 amp and got an answer

Is it the correct answer though? That's why I'm here.

 

[Pete999]

Is it the correct answer though? That's why I'm here.

Think I miss read the original question, get back to you later

 

[Morley2012]

P = I x V ( 10 x 230 = 2300W or 2.3kw )

2300/0.8/230 = 12.5a

Scrap that it's asking for power not current

 

[shnabz]

P = I x V ( 10 x 230 = 2300W or 2.3kw )

2300/0.8/230 = 12.5a

Scrap that it's asking for power not current

Power = Current X Voltage
12.5 x 230 = 2.875KW

 

[Morley2012]

P = I x V ( 10 x 230 = 2300W or 2.3kw )

2300/0.8/230 = 12.5A

P = I x Pf x V ( 12.5 x 0.8 x 230 = 2.3kw )

I = P / V ( 2300/230 = 10a )

My answer is 2300w but I've been up since 4am I'm sure someone more knowledgeable will pop by shortly.

 

[shnabz]

P = I x V ( 10 x 230 = 2300W or 2.3kw )

2300/0.8/230 = 12.5A

P = I x V ( 12.5 x 0.8 x 230 = 2.3kw )

I = P / V ( 2300/230 = 10a )

My answer is 2300w but I've been up since 4am I'm sure someone more knowledgeable will pop by shortly.

That's because you did 12.5 x 0.8 x 230. Instead of 12.5 x 230

 

[Simonslimline]

Has anyone been shown the fluorescent light example at college, with the PF correction cap being switched in and out of the circuit?

What will happen when it is switched out of circuit therefore giving it a power factor lower than unity?

 

[shnabz]

Has anyone been shown the fluorescent light example at college, with the PF correction cap being switched in and out of the circuit?

What will happen when it is switched out of circuit therefore giving it a power factor lower than unity?

It would probably draw more current

 

[pitkin2020]

Has anyone been shown the fluorescent light example at college, with the PF correction cap being switched in and out of the circuit?

What will happen when it is switched out of circuit therefore giving it a power factor lower than unity?

I assume the current being drawn will increase