Step Down Transformer Equation
Ns = number of turns in secondary. Np = number of turns in primary. Vs = Voltage in secondary. Vp = Voltage in primary.
How do you calculate step-up and step down transformer?
Point to Remember
It depends on how it is connected in the circuit. If the input supply is supplied on the low-voltage winding, it becomes a step-up transformer. On the other hand, if the input power is supplied on the high voltage winding, the transformer becomes a step-down transformer.
How do you size a step down transformer?
Calculate an example as follows. A 120-volt motor has a load amperage of 5 amps. Multiply 120 volts times 5 amps this equals 600VA now lets multiply the 125 percent start factor. Take 600 times 1.25 this equals 720VA and most transformers are sized by a factor of 25VA or 50VA.
