PACCAR Interview Questions and Answers

IDMT relay is used for overcurrent protection while transformer differential relay is used for differential protection.

• IDMT relay operates based on inverse time-current characteristic curve

• Transformer differential relay compares the currents entering and leaving the transformer windings

• IDMT relay is used for protecting electrical equipment from overcurrents

• Transformer differential relay is used for detecting internal faults in transformers

Types of transformer losses include copper losses, iron losses, and stray losses.

• Copper losses: Also known as I^2R losses, occur in the copper windings of the transformer due to resistance.

• Iron losses: Also known as core losses, occur in the transformer core due to hysteresis and eddy currents.

• Stray losses: Occur due to leakage flux and imperfect magnetic coupling between the windings.

• Examples: An example of copper losses would be heat generated in the transformer windings. A...read more

Solar panels convert sunlight into electricity through photovoltaic cells.

• Solar panels contain photovoltaic cells that convert sunlight into electricity

• When sunlight hits the cells, it excites electrons, creating a flow of electricity

• The electricity generated can be used to power homes, businesses, or stored in batteries for later use

Star delta starter is a type of reduced voltage starter used for starting high power motors.

• Consists of two contactors - one for star connection and one for delta connection

• Reduces starting current and torque on the motor

• Commonly used in industrial applications for motors above 5 HP

Types of rotors in generators include salient pole rotor and cylindrical rotor.

• Salient pole rotor has projecting poles with concentrated windings, used in low-speed applications.

• Cylindrical rotor has distributed windings and is used in high-speed applications.

• Other types include wound rotor and squirrel cage rotor.

• Wound rotor has three-phase windings connected to slip rings, used in variable speed applications.

• Squirrel cage rotor has short-circuited conductors, used in high-s...read more