more efficiency help needed

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searley

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hi.

an electric machine has a power output of 1500 watts.the input current is 4a and the applied voltage is 400v.the efficiency of the machine will be ?.

can some one please show me how to work this out.cheers,Pray

 

DonkeyDong

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Depends on how "simple" you want the calculation to be (single or three phase):

You could simplify it and say:

Input Power = 400V * 4A = 1600W

Efficiency = (1500/1600) * 100 = 93.75% efficient (or 0.94 as often stated)

But in reality you should take into account Pf, so:

Input Power = SQRT(3) * V * I * Pf (assume a Pf of 0.85)

Therefore:

Input Power = 1.732 * 400 * 4 * 0.85 = 2355.52

Thus:

Efficienty = (1500/2355.52) * 100 = 63.68% (or as often stated 0.64)

Hope this helps,

D.

 
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Depends on how "simple" you want the calculation to be (single or three phase):You could simplify it and say:

Input Power = 400V * 4A = 1600W

Efficiency = (1500/1600) * 100 = 93.75% efficient (or 0.94 as often stated)

But in reality you should take into account Pf, so:

Input Power = SQRT(3) * V * I * Pf (assume a Pf of 0.85)

Therefore:

Input Power = 1.732 * 400 * 4 * 0.85 = 2355.52

Thus:

Efficienty = (1500/2355.52) * 100 = 63.68% (or as often stated 0.64)

Hope this helps,

D.
Applaud Smiley:D

Carol VordermanII,

Apache & DonkeyDong

they like their numbers...

can you get the 9 letter words?

"NOBEERKME" Guiness Drink

 

searley

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cheers top man.i can get on now with the rest of course work.thanks

 
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In the office again.
I really likes the second one - know the first one.

What`s it mean though?

On the subject - do you know what either of these are?

Bromochlorodiflouromethane?

Polytetrafluoroethylene?

(I`ll post the answers tomorrow) - no googling

 
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I really likes the second one - know the first one.What`s it mean though?

On the subject - do you know what either of these are?

Bromochlorodiflouromethane? CFC's?

Polytetrafluoroethylene? PTFE or Teflon

(I`ll post the answers tomorrow) - no googling
It's a lung disease miners get, a kind of silicosis

 
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