Modern synchronous motors have:

Modern synchronous motors have:

• A. Both Brushes and Slip Rings.
• B. Brushes, But No Slip Rings.
• C. Slip Rings, But No Brushes.
• D. Neither Brushes Nor Slip Rings.

Answer: (D)

Modern synchronous motors energize the rotor field without relying on physical contact through brushes or slip rings. In many current designs, excitation is provided by a brushless system: a small exciter on the shaft generates the DC for the rotor via rotating rectifiers, or the rotor uses permanent magnets that don’t require separate DC excitation at all. This eliminates the need for brushes and slip rings entirely. The older approach used in some legacy machines involved feeding the rotor winding through brushes and slip rings, but that setup is not typical of modern designs. So, the best description is that modern synchronous motors have neither brushes nor slip rings.

Modern synchronous motors energize the rotor field without relying on physical contact through brushes or slip rings. In many current designs, excitation is provided by a brushless system: a small exciter on the shaft generates the DC for the rotor via rotating rectifiers, or the rotor uses permanent magnets that don’t require separate DC excitation at all. This eliminates the need for brushes and slip rings entirely. The older approach used in some legacy machines involved feeding the rotor winding through brushes and slip rings, but that setup is not typical of modern designs. So, the best description is that modern synchronous motors have neither brushes nor slip rings.