CET460S Electrical Equipment Flashcards

Comprehensive vocabulary flashcards covering DC/AC circuit fundamentals, motor efficiency, transformer calculations, and electromagnetic induction based on the CET460S lecture workbook.

DC Current

Electrical current that flows in one direction.

Series Circuit

A circuit configuration where all components share the same current.

Parallel Circuit

A circuit configuration where all branches share the same voltage.

Total Resistance (Series)

The sum of all resistors in a series circuit ($R_T = R1 + R2 + … + R_n$).

Total Resistance (Parallel)

Calculated using the reciprocal formula: $\frac{1}{R_T} = \frac{1}{R1} + \frac{1}{R2} + … + \frac{1}{R_n}$.

Efficiency ($\eta$)

The ratio of output power ($P_{out}$) to input power ($P_{in}$), expressed as $\eta = \frac{P_{out}}{P_{in}}$.

Power Loss ($P_{loss}$)

The difference between input power and output power, calculated as $P_{loss} = P_{in} - P_{out}$.

Resistive Heating

Efficiency losses in motor windings caused by current flowing through resistance, also known as $I^2R$ losses.

Windage

Mechanical efficiency loss in motors caused by air resistance on the rotating shaft.

AC Motors

Motors that run on alternating current and are classified into induction or synchronous types.

DC Motors

Motors that run on direct current and are preferred for precise, stepless speed control and easy direction reversal.

Single-Phase AC Motor

A smaller motor typically used in residential applications (under $1\,kW$) that requires a starting mechanism.

Three-Phase AC Motor

An industrial motor (typically above $5\,kW$) that is self-starting, highly efficient, and produces smooth torque.

Transformer

A device that changes voltage and current values across a turns ratio without changing the frequency.

Turns Ratio

The proportional relationship between the number of primary turns ($N_p$) and secondary turns ($N_s$), defined as $\frac{N_p}{N_s} = \frac{V_p}{V_s}$.

Electromagnetic Induction

The generation of an electromotive force (EMF) in a conductor when it is exposed to a changing magnetic field.

Faraday’s Law

The principle stating that a changing magnetic flux induces a voltage (EMF) across the terminals of a coil.

Generator

A device that converts mechanical energy into electrical energy (AC output) using electromagnetic induction.

Bearing Wear

A consequence of poor motor maintenance where lack of lubrication causes metal-on-metal contact and potential shaft seizure.

Commutator

A component used in DC motors to maintain current direction in the rotor windings.