What will happen to the secondary voltage if a 240v transformer is connected to a 208v supply voltage?

When a transformer is connected to a supply voltage that is lower than its rated voltage, the secondary voltage will consequently be lower than expected. In this scenario, a 240V transformer is designed to operate efficiently at 240 volts; however, if it is fed with only 208 volts, the transformer is unable to reach its designed operational capability.

Transformers operate based on the turns ratio, which determines the relationship between the primary and secondary voltages. Since the input voltage is lower than the nominal voltage the transformer is designed for, the output (secondary) voltage will also decrease proportionally.

This behavior can be attributed to the principle that the voltage output of a transformer directly correlates with the input voltage supplied and the turns ratio of the transformer windings. Therefore, with a reduced supply voltage, the resulting secondary voltage will indeed be less than the transformer’s rated output, which aligns with the correct answer provided.