formula

[jamieb]

if i have 4160v thats drawing 30 amps, what is the formula to calculate the amperage on the 600v secondary??....thanks

 

[SparkyHC]

Assuming three phase primary to three phase secondary:
[(4160*sqrt 3)(30A)]/(600*sqrt 3)= 208 amperes
of course this can be simplified...
Remove the sqrt 3's for single phase to single phase transformers.
Simply P=IE with Pin = Pout...when using this with three phase don't forget to multiply the voltage times the square root of three.

 

[jumper]

Here ya go.
http://www.elec-toolbox.com/Formulas/Transformer/xfmrform.htm

 

[LarryFine]

Remove the sqrt 3's for single phase to single phase transformers.

Or for 3ph to 3ph.

 

[zog]

if i have 4160v thats drawing 30 amps, what is the formula to calculate the amperage on the 600v secondary??....thanks

(Ep*Ip)=(Es*Is)

Assumes zero losses in transformer

 

[jamieb]

(Ep*Ip)=(Es*Is)

Assumes zero losses in transformer

this tx is 30 years old, any idea what kind of % loss could be factored in..even a rough idea???

 

[jghrist]

this tx is 30 years old, any idea what kind of % loss could be factored in..even a rough idea???

Very rough idea:
full load loss 1%
no load loss 0.3%

500 kVA transformer at 500 kVA load: 0.01*500 + 0.003*500 = 6.5 kW
500 kVA transformer at 250 kVA load: 0.01*(250/500)^2*500 + 0.003*500 = 2.75 kW

 

[jamieb]

thanks alot guys!! appreciate the input