Appendix 2: Glossary of Terms for Motors and Sensors

This glossary provides definitions for key terms used in the modules on DC Motors, Stepper Motors, AC Motors, and Fundamentals of Sensors.

General Motor Terms:

• Motor: A device that converts electrical energy into mechanical energy (rotation).
• Stator: The stationary part of a motor that typically houses the electromagnets.
• Rotor: The rotating part of a motor that generates torque.
• Shaft: The central axis of the rotor that transmits rotational power.
• Torque: The twisting force generated by a motor, measured in Newton-meters (Nm).
• Speed: The rotational rate of the motor shaft, typically measured in revolutions per minute (RPM).
• Power: The rate at which the motor converts electrical energy into mechanical work, measured in watts (W).
• Efficiency: The ratio of useful mechanical power output to the electrical power input of the motor.

DC Motor Terms:

• Brushed DC Motor: A DC motor that uses brushes and a commutator to achieve continuous rotation.
• Permanent Magnet DC Motor (PMDC Motor): A DC motor that utilizes permanent magnets to generate the magnetic field in the stator.
• Commutation: The process of switching the current flow in the windings of a brushed DC motor to ensure continuous rotation.
• SCR (Silicon Controlled Rectifier): A thyristor device used for controlling power in DC motors powered by AC source.
• H-Bridge: An electronic circuit that allows for bi-directional control of a DC motor (forward and reverse).

Stepper Motor Terms:

• Stepper Motor: A type of DC motor that rotates in discrete steps based on electrical pulses.
• Step Angle: The angular movement of the motor shaft per step.
• Holding Torque: The torque that the stepper motor can resist without losing position.
• Microstepping: A technique that allows a stepper motor to achieve finer positioning than its basic step angle.
• Open-Loop Control: Controlling a stepper motor without feedback on its actual position.
• Closed-Loop Control: Controlling a stepper motor with feedback from an encoder to ensure accurate positioning.

AC Motor Terms:

• AC Motor: A motor that operates on alternating current (AC) power.
• Induction Motor: A type of AC motor where the rotating magnetic field in the stator induces current flow in the rotor.
• Single-Phase Induction Motor: An AC motor powered by a single-phase AC supply.
• Three-Phase Induction Motor: A more powerful and efficient AC motor powered by a three-phase AC supply.
• Synchronous Motor: An AC motor that maintains a constant speed in synchronization with the frequency of the AC power supply.
• Power Factor: The ratio of real power used by the motor to the apparent power delivered by the AC supply.
• Variable Frequency Drive (VFD): An electronic device that controls the speed of an AC motor by varying the frequency of the AC power supply.

Sensor Terms:

• Sensor: A device that detects and responds to a physical stimulus or change in the environment.
• Transducer: A broader term encompassing any device that converts one form of energy into another (e.g., sensor, microphone, speaker).
• Resolution: The smallest detectable change in the physical quantity a sensor can measure.
• Accuracy: The closeness of a sensor’s measurement to the true value of the physical quantity being measured.
• Calibration: The process of adjusting a sensor to ensure its readings are accurate and consistent.
• Proximity Sensor: A sensor that detects the presence or absence of an object without physical contact.
• Encoder: A rotary sensor that converts shaft rotation into electrical signals (e.g., digital pulses).