Transformer power transfer
Electric power can be calculated using the equation:
Electric power = voltage V 脳 current I
P = VI
Where:
- P = electric power in watts, W
- V = voltage in volts, V
- I = current in amperes, A
Assuming that a transformerAn electrical device that increases, or decreases, the voltage (p.d.) of an alternating current. is 100 % efficient, the following equation can be used to calculate the power output from the transformer:
Input power = output power
VsIs = VpIp
Question
A step-down transformer converts 11,500 V into 230 V.
The power output is used to run a 2000 W kettle.
Calculate the current flowing in the primary coil.
Input power = output power
Output power = 2000 W
Input power = VpIp
Vp = 11,500 V
11,500 v Ip = 2000
Ip = \(\frac{2000}{11,500}\)
Ip = 0.17 A
The current flowing in the primary coil is 0.17 A.