Single Phase Transformer Question

[leena2k6]

A single phase transformer supplies a 2.2KW electric heater at 110V. If the primary current is 8.695A, calculate the primary voltage?
Any help on this appreciated!

Many Thanks
Leena

 

[uncle betty]

A Transformer Power In = Power Out.

Power = Volts x Amps

2.2kw = Primary Voltage x 8.695 Amps

Primary Voltage = 2,200/8.695

Primary Voltage = 253 Volts

 

[MarkieSparkie]

Assuming a lossless ideal transformer and unity power factor:
From the lossless transformer equation Vp/Vs=Np/Ns=Is/Ip therefore:
Vp=(Vs x Is)/Ip
Where Is=Ps/Vs
Vp=(110V x 2200W/110V)/8.695A
Vp=2200W/8.695A
Vp=253V

 

[Knobhead]

Homework is meant to be done at home!

 

[telectrix]

it's a stupid question anyway. whoever heard of a 100% efficient transformer. (apart from optimus whatever)