How to Determine Voltage Drop in a Y-Connected System?

What is the voltage drop between any phase wire and the grounded neutral center tap of the windings in a 208-volt Y-connected system?

Choose one:

A. 120 volts

B. 150 volts

C. 180 volts

D. 208 volts

Answer:

The correct answer is A. 120 volts.

In a 208-volt Y-connected system, the voltage drop between any phase wire and the grounded neutral center tap of the windings is 120 volts. This is because in a Y-connected system, the phase voltage is 208 volts, and the phase voltage is the voltage between any phase wire and the neutral center point. The neutral center point is connected to ground, which means the voltage between any phase wire and ground is the same as the phase voltage.

Therefore, the voltage drop is calculated as 208 volts - 0 volts (ground) = 208 volts. However, when we convert the Y-connected system to a Δ-connected system (delta connection), the voltage between any two phase terminals will be 208 volts.

Understanding how voltage drop works in different electrical systems is essential for maintaining safety and efficiency in power distribution. By knowing the voltage drop, engineers and electricians can ensure that electrical devices receive the correct voltage and operate properly.