Question

A transformation has a voyage 480 V and current 2.5 A on the primary side and 40 V on the secondary . What is the secondary current on the load ?

Answer 1

According to the law of conservation of energy for an ideal transformer, the following expression is valid:

$$U_p I_p =U_sI_s$$

where the voltage is 480 V and the current is 2.5 A on the primary side:

$$U_p=480V,\space I_p=2.5A$$

and 40 V voltage and current on the secondary side:

$$U_s=40V, \space I_S=\frac{U_pI_p}{U_s}=\frac{480V\cdot2.5A}{40V}=30A$$

Answer: the secondary current on the load is 30A