Which type of sensor provides generator and rotor speed data to the PLC?

• A. Optical encoders
• B. Potentiometers
• C. Inductive sensors
• D. Hall effect sensors

Answer: (C)

Speed data from rotating parts is often gathered by a sensor that produces a pulse train as metal features pass by. An inductive proximity sensor fits this role because it detects metallic targets on a rotor or gear without contact, generating pulses each time a tooth or metal feature passes the sensor. The PLC counts those pulses and converts the frequency into RPM, giving real-time generator and rotor speed information. Inductive sensing is particularly robust in harsh industrial environments and doesn’t rely on light or line-of-sight, which helps maintain reliable speed data around moving machinery. Other options may measure position or rely on magnetic fields, but they aren’t as direct or durable for continuously reporting speed from metal-moving parts.